git subrepo clone ../cabal-plan cabal-plan

subrepo:
  subdir:   "cabal-plan"
  merged:   "34506ab"
upstream:
  origin:   "../cabal-plan"
  branch:   "master"
  commit:   "34506ab"
git-subrepo:
  version:  "0.3.1"
  origin:   "https://github.com/ingydotnet/git-subrepo.git"
  commit:   "a7ee886"

15 files changed, 3920 insertions, 0 deletions

diff --git a/cabal-plan/.gitignore b/cabal-plan/.gitignore
new file mode 100644
index 0000000..1b394da
--- /dev/null
+++ b/cabal-plan/.gitignore
@@ -0,0 +1,5 @@
+*~
+/dist-newstyle/
+/dist/
+/.ghc.environment.*
+/cabal.project.local
diff --git a/cabal-plan/.gitrepo b/cabal-plan/.gitrepo
new file mode 100644
index 0000000..c0cb75b
--- /dev/null
+++ b/cabal-plan/.gitrepo
@@ -0,0 +1,11 @@
+; DO NOT EDIT (unless you know what you are doing)
+;
+; This subdirectory is a git "subrepo", and this file is maintained by the
+; git-subrepo command. See https://github.com/git-commands/git-subrepo#readme
+;
+[subrepo]
+	remote = ../cabal-plan
+	branch = master
+	commit = 34506abf26df4275e8c90771587d152d1c8531f1
+	parent = 12e1be31c09161dec1fa70f15ede84ba9965a365
+	cmdver = 0.3.1
diff --git a/cabal-plan/.travis.yml b/cabal-plan/.travis.yml
new file mode 100644
index 0000000..0cb96f8
--- /dev/null
+++ b/cabal-plan/.travis.yml
@@ -0,0 +1,110 @@
+# This Travis job script has been generated by a script via
+#
+#   runghc make_travis_yml_2.hs '-o' '.travis.yml' 'cabal-plan.cabal'
+#
+# For more information, see https://github.com/hvr/multi-ghc-travis
+#
+language: c
+sudo: false
+
+git:
+  submodules: false  # whether to recursively clone submodules
+
+cache:
+  directories:
+    - $HOME/.cabal/packages
+    - $HOME/.cabal/store
+
+before_cache:
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/build-reports.log
+  # remove files that are regenerated by 'cabal update'
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/00-index.*
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/*.json
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/01-index.cache
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/01-index.tar
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/01-index.tar.idx
+
+  - rm -rfv $HOME/.cabal/packages/head.hackage
+
+matrix:
+  include:
+    - compiler: "ghc-8.4.3"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.2,ghc-8.4.3], sources: [hvr-ghc]}}
+    - compiler: "ghc-8.2.2"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.2,ghc-8.2.2], sources: [hvr-ghc]}}
+    - compiler: "ghc-8.0.2"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.2,ghc-8.0.2], sources: [hvr-ghc]}}
+    - compiler: "ghc-7.10.3"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.2,ghc-7.10.3], sources: [hvr-ghc]}}
+    - compiler: "ghc-7.8.4"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.2,ghc-7.8.4], sources: [hvr-ghc]}}
+    - compiler: "ghc-7.6.3"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.2,ghc-7.6.3], sources: [hvr-ghc]}}
+
+before_install:
+  - HC=${CC}
+  - HCPKG=${HC/ghc/ghc-pkg}
+  - unset CC
+  - ROOTDIR=$(pwd)
+  - mkdir -p $HOME/.local/bin
+  - "PATH=/opt/ghc/bin:/opt/ghc-ppa-tools/bin:$HOME/local/bin:$PATH"
+  - HCNUMVER=$(( $(${HC} --numeric-version|sed -E 's/([0-9]+)\.([0-9]+)\.([0-9]+).*/\1 * 10000 + \2 * 100 + \3/') ))
+  - echo $HCNUMVER
+
+install:
+  - cabal --version
+  - echo "$(${HC} --version) [$(${HC} --print-project-git-commit-id 2> /dev/null || echo '?')]"
+  - BENCH=${BENCH---enable-benchmarks}
+  - TEST=${TEST---enable-tests}
+  - HADDOCK=${HADDOCK-true}
+  - INSTALLED=${INSTALLED-true}
+  - GHCHEAD=${GHCHEAD-false}
+  - travis_retry cabal update -v
+  - "sed -i.bak 's/^jobs:/-- jobs:/' ${HOME}/.cabal/config"
+  - rm -fv cabal.project cabal.project.local
+  - grep -Ev -- '^\s*--' ${HOME}/.cabal/config | grep -Ev '^\s*$'
+  - "printf 'packages: \".\"\\n' > cabal.project"
+  - cat cabal.project
+  - if [ -f "./configure.ac" ]; then
+      (cd "." && autoreconf -i);
+    fi
+  - rm -f cabal.project.freeze
+  - cabal new-build -w ${HC} ${TEST} ${BENCH} --project-file="cabal.project" --dep -j2 all
+  - cabal new-build -w ${HC} --disable-tests --disable-benchmarks --project-file="cabal.project" --dep -j2 all
+  - rm -rf .ghc.environment.* "."/dist
+  - DISTDIR=$(mktemp -d /tmp/dist-test.XXXX)
+
+# Here starts the actual work to be performed for the package under test;
+# any command which exits with a non-zero exit code causes the build to fail.
+script:
+  # test that source-distributions can be generated
+  - (cd "." && cabal sdist)
+  - mv "."/dist/cabal-plan-*.tar.gz ${DISTDIR}/
+  - cd ${DISTDIR} || false
+  - find . -maxdepth 1 -name '*.tar.gz' -exec tar -xvf '{}' \;
+  - "printf 'packages: cabal-plan-*/*.cabal\\n' > cabal.project"
+  - cat cabal.project
+  # this builds all libraries and executables (without tests/benchmarks)
+  - cabal new-build -w ${HC} --disable-tests --disable-benchmarks all
+
+  # Build with installed constraints for packages in global-db
+  - if $INSTALLED; then echo cabal new-build -w ${HC} --disable-tests --disable-benchmarks $(${HCPKG} list --global --simple-output --names-only | sed 's/\([a-zA-Z0-9-]\{1,\}\) */--constraint="\1 installed" /g') all | sh; else echo "Not building with installed constraints"; fi
+
+  # build & run tests, build benchmarks
+  - cabal new-build -w ${HC} ${TEST} ${BENCH} all
+
+  # cabal check
+  - (cd cabal-plan-* && cabal check)
+
+  # haddock
+  - rm -rf ./dist-newstyle
+  - if $HADDOCK; then cabal new-haddock -w ${HC} ${TEST} ${BENCH} all; else echo "Skipping haddock generation";fi
+
+# REGENDATA ["-o",".travis.yml","cabal-plan.cabal"]
+# EOF
diff --git a/cabal-plan/ChangeLog.md b/cabal-plan/ChangeLog.md
new file mode 100644
index 0000000..4691d9d
--- /dev/null
+++ b/cabal-plan/ChangeLog.md
@@ -0,0 +1,50 @@
+# Revision history for `cabal-plan`
+
+## 0.4.0.0
+
+### `lib:cabal-plan` Library
+
+* New `SearchPlanJson` type to specify strategy for locating `plan.json`
+* Add `SearchPlanJson` parameter to `findAndDecodePlanJson` function and change return type
+* Expose separate `findProjectRoot` operation
+
+### `exe:cabal-plan` Executable
+
+* New command `license-report` (requires Cabal flag `license-report` to be active)
+
+## 0.3.0.0
+
+### `lib:cabal-plan` Library
+
+* Add support for foreign-lib components.
+* Add support for `dist-dir` `plan.json` field.
+* Make `Sha256` type abstract and add new `sha256{To,From}ByteString`
+  conversion functions, as well as the new `parseSha256` function.
+* Introduce `FlagName` newtype.
+* Add `FromJSONKey`/`ToJSONKey` instances for `UnitId`, `PackageName`, and `PkgId`.
+
+### `exe:cabal-plan` Executable
+
+* smart completer for list-bin/list-bins pattern
+* new command `topo` (printing out topographic sorting of install-plan)
+* `dot` prints component dependency graph. New options:
+    - `--tred` transitive reduction
+    - `--tred-weights` Adjust edge thickness during transitive reduction
+    - `--path-from pkgA --path-from pkgB` Highlight dependency paths from *pkgA* to *pkgB*
+    - `--revdep pkg` highlight reverse dependencies of pkg in the install plan
+
+## 0.2.0.0
+
+* Add an optional `--builddir` argument to all commands and to `findAndDecodePlanJson` function.
+* Add experimental support for underlining.
+* Reimplement CLI with `optparse-applicative`.
+* Add new sub-command `list-bins` and change semantics of existing `list-bin` sub-cmd.
+
+### 0.1.1.0
+
+* Add `cabal-plan fingerprint` command for printing
+  sha256 sums of source tarballs.
+
+## 0.1.0.0
+
+* First version. Released on an unsuspecting world.
diff --git a/cabal-plan/LICENSE.GPLv2 b/cabal-plan/LICENSE.GPLv2
new file mode 100644
index 0000000..1f53f40
--- /dev/null
+++ b/cabal-plan/LICENSE.GPLv2
@@ -0,0 +1,339 @@
+             GNU GENERAL PUBLIC LICENSE
+                Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                     Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Lesser General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
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+These restrictions translate to certain responsibilities for you if you
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+(2) offer you this license which gives you legal permission to copy,
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+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
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+Activities other than copying, distribution and modification are not
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+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
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+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
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+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
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+  2. You may modify your copy or copies of the Program or any portion
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+
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+    c) If the modified program normally reads commands interactively
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+These requirements apply to the modified work as a whole.  If
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+distribute the same sections as part of a whole which is a work based
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+entire whole, and thus to each and every part regardless of who wrote it.
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+with the Program (or with a work based on the Program) on a volume of
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+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
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diff --git a/cabal-plan/LICENSE.GPLv3 b/cabal-plan/LICENSE.GPLv3
new file mode 100644
index 0000000..45644ff
--- /dev/null
+++ b/cabal-plan/LICENSE.GPLv3
@@ -0,0 +1,674 @@
+              GNU GENERAL PUBLIC LICENSE
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+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+              END OF TERMS AND CONDITIONS
+
+     How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.
diff --git a/cabal-plan/Setup.hs b/cabal-plan/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/cabal-plan/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/cabal-plan/cabal-plan.cabal b/cabal-plan/cabal-plan.cabal
new file mode 100644
index 0000000..72aaccd
--- /dev/null
+++ b/cabal-plan/cabal-plan.cabal
@@ -0,0 +1,132 @@
+cabal-version:       2.0
+name:                cabal-plan
+version:             0.4.0.0
+
+synopsis:            Library and utiltity for processing cabal's plan.json file
+description: {
+This package provides a library for decoding @plan.json@ files as
+well as the simple tool @cabal-plan@ for extracting and pretty printing
+the information contained in the @plan.json@ file.
+.
+@plan.json@ files are generated by [cabal](https://hackage.haskell.org/package/cabal-install)'s [nix-style local builds](http://cabal.readthedocs.io/en/latest/nix-local-build.html) and contain detailed information about the build/install plan computed by the cabal solver.
+}
+
+bug-reports:         https://github.com/hvr/cabal-plan/issues
+X-SPDX-License-Identifier: GPL-2.0-or-later
+license:             GPL-2
+license-files:       LICENSE.GPLv2 LICENSE.GPLv3 src-topograph/LICENSE
+author:              Herbert Valerio Riedel
+maintainer:          hvr@gnu.org
+copyright:           2016 Herbert Valerio Riedel
+category:            Development
+build-type:          Simple
+
+tested-with:
+  GHC==8.4.3,
+  GHC==8.2.2,
+  GHC==8.0.2,
+  GHC==7.10.3,
+  GHC==7.8.4,
+  GHC==7.6.3
+
+extra-source-files:
+  ChangeLog.md
+
+----------------------------------------------------------------------------
+
+flag exe
+  -- this automatic flag allows the cabal solver to disable the exe:cabal-plan component (& its build-deps);
+  -- IOW, emulate https://github.com/haskell/cabal/issues/4660
+  description: Enable @exe:cabal-plan@ component
+
+flag license-report
+  description: Enable @license-report@ sub-command (only relevant when the @exe@ flag is active)
+  manual: True
+  default: False
+
+flag _
+  description: Enable underlining of primary unit-ids
+  manual: True
+  default: False
+
+library
+  default-language:    Haskell2010
+  other-extensions:    OverloadedStrings
+                       GeneralizedNewtypeDeriving
+                       RecordWildCards
+  exposed-modules:     Cabal.Plan
+
+  build-depends:       base              (>= 4.6 && <4.10) || ^>= 4.10 || ^>=4.11
+                     , aeson             ^>= 1.2.0 || ^>= 1.3.0 || ^>=1.4.0.0
+                     , bytestring        ^>= 0.10.0
+                     , containers        ^>= 0.5.0
+                     , text              ^>= 1.2.2
+                     , directory         ^>= 1.2.0 || ^>= 1.3.0
+                     , filepath          ^>= 1.3.0 || ^>= 1.4.0
+                     , base16-bytestring ^>= 0.1.1
+
+  hs-source-dirs:      src
+
+  ghc-options: -Wall
+
+library topograph
+  default-language:    Haskell2010
+  other-extensions:    RankNTypes ScopedTypeVariables RecordWildCards
+  exposed-modules:     Topograph
+
+  build-depends:       base              (>= 4.6 && <4.10) || ^>= 4.10 || ^>= 4.11
+                     , base-compat       ^>= 0.9.3 || ^>=0.10.1
+                     , base-orphans      ^>= 0.6 || ^>=0.7 || ^>=0.8
+                     , containers        ^>= 0.5.0
+                     , vector            ^>= 0.12.0.1
+
+  hs-source-dirs:      src-topograph
+
+executable cabal-plan
+  default-language:    Haskell2010
+  other-extensions:    RecordWildCards
+
+  hs-source-dirs: src-exe
+  main-is: cabal-plan.hs
+  other-modules: Paths_cabal_plan, LicenseReport
+  autogen-modules: Paths_cabal_plan
+
+  if flag(exe)
+    -- dependencies w/ inherited version ranges via 'cabal-plan' library
+    build-depends: cabal-plan
+                 , topograph
+                 , base
+                 , text
+                 , containers
+                 , bytestring
+                 , directory
+
+    -- dependencies which require version bounds
+    build-depends: mtl            ^>= 2.2.1
+                 , ansi-terminal  ^>= 0.6.2 || ^>= 0.8.0.2
+                 , base-compat    ^>= 0.9.3 || ^>=0.10.1
+                 , optparse-applicative ^>= 0.13.0 || ^>= 0.14.0
+                 , parsec         ^>= 3.1.11
+                 , vector         ^>= 0.12.0.1
+
+
+    if flag(license-report)
+      build-depends: Cabal    ^>= 2.2.0.1
+                   , tar      ^>= 0.5.1.0
+                   , zlib     ^>= 0.6.2
+                   , filepath ^>= 1.4.1.2
+
+    if !impl(ghc >= 8.0)
+      build-depends:
+                   semigroups     ^>= 0.18.3
+
+    if flag(_)
+      cpp-options: -DUNDERLINE_SUPPORT
+  else
+    buildable: False
+
+  ghc-options: -Wall
+
+source-repository head
+  type: git
+  location: https://github.com/hvr/cabal-plan
diff --git a/cabal-plan/cabal.project b/cabal-plan/cabal.project
new file mode 100644
index 0000000..0c693dc
--- /dev/null
+++ b/cabal-plan/cabal.project
@@ -0,0 +1,4 @@
+packages: .
+
+package cabal-plan
+  flags: +exe +license-report
diff --git a/cabal-plan/license-report.css b/cabal-plan/license-report.css
new file mode 100644
index 0000000..a5ffa72
--- /dev/null
+++ b/cabal-plan/license-report.css
@@ -0,0 +1,334 @@
+/* from https://gist.github.com/killercup/5917178 declared as public domain or CC0 
+ *
+ *  pandoc -c license-report.css --self-contained -s license.md > license.html
+ *
+ */
+
+html {
+  font-size: 100%;
+  overflow-y: scroll;
+  -webkit-text-size-adjust: 100%;
+  -ms-text-size-adjust: 100%;
+}
+
+body {
+  color: #444;
+  font-family: Georgia, Palatino, 'Palatino Linotype', Times, 'Times New Roman', serif;
+  font-size: 12px;
+  line-height: 1.7;
+  padding: 1em;
+  margin: auto;
+  /* max-width: 42em; */
+  background: #fefefe;
+}
+
+a {
+  color: #0645ad;
+  text-decoration: none;
+}
+
+a:visited {
+  color: #0b0080;
+}
+
+a:hover {
+  color: #06e;
+}
+
+a:active {
+  color: #faa700;
+}
+
+a:focus {
+  outline: thin dotted;
+}
+
+*::-moz-selection {
+  background: rgba(255, 255, 0, 0.3);
+  color: #000;
+}
+
+*::selection {
+  background: rgba(255, 255, 0, 0.3);
+  color: #000;
+}
+
+a::-moz-selection {
+  background: rgba(255, 255, 0, 0.3);
+  color: #0645ad;
+}
+
+a::selection {
+  background: rgba(255, 255, 0, 0.3);
+  color: #0645ad;
+}
+
+p {
+  margin: 1em 0;
+}
+
+img {
+  max-width: 100%;
+}
+
+h1, h2, h3, h4, h5, h6 {
+  color: #111;
+  line-height: 125%;
+  margin-top: 2em;
+  font-weight: normal;
+}
+
+h4, h5, h6 {
+  font-weight: bold;
+}
+
+h1 {
+  font-size: 2.5em;
+}
+
+h2 {
+  font-size: 2em;
+}
+
+h3 {
+  font-size: 1.5em;
+}
+
+h4 {
+  font-size: 1.2em;
+}
+
+h5 {
+  font-size: 1em;
+}
+
+h6 {
+  font-size: 0.9em;
+}
+
+blockquote {
+  color: #666666;
+  margin: 0;
+  padding-left: 3em;
+  border-left: 0.5em #EEE solid;
+}
+
+hr {
+  display: block;
+  height: 2px;
+  border: 0;
+  border-top: 1px solid #aaa;
+  border-bottom: 1px solid #eee;
+  margin: 1em 0;
+  padding: 0;
+}
+
+pre, code, kbd, samp {
+  color: #000;
+  font-family: monospace, monospace;
+  _font-family: 'courier new', monospace;
+  font-size: 0.98em;
+}
+
+pre {
+  white-space: pre;
+  white-space: pre-wrap;
+  word-wrap: break-word;
+}
+
+b, strong {
+  font-weight: bold;
+}
+
+dfn {
+  font-style: italic;
+}
+
+ins {
+  background: #ff9;
+  color: #000;
+  text-decoration: none;
+}
+
+mark {
+  background: #ff0;
+  color: #000;
+  font-style: italic;
+  font-weight: bold;
+}
+
+sub, sup {
+  font-size: 75%;
+  line-height: 0;
+  position: relative;
+  vertical-align: baseline;
+}
+
+sup {
+  top: -0.5em;
+}
+
+sub {
+  bottom: -0.25em;
+}
+
+ul, ol {
+  margin: 1em 0;
+  padding: 0 0 0 2em;
+}
+
+li p:last-child {
+  margin-bottom: 0;
+}
+
+ul ul, ol ol {
+  margin: .3em 0;
+}
+
+dl {
+  margin-bottom: 1em;
+}
+
+dt {
+  font-weight: bold;
+  margin-bottom: .8em;
+}
+
+dd {
+  margin: 0 0 .8em 2em;
+}
+
+dd:last-child {
+  margin-bottom: 0;
+}
+
+img {
+  border: 0;
+  -ms-interpolation-mode: bicubic;
+  vertical-align: middle;
+}
+
+figure {
+  display: block;
+  text-align: center;
+  margin: 1em 0;
+}
+
+figure img {
+  border: none;
+  margin: 0 auto;
+}
+
+figcaption {
+  font-size: 0.8em;
+  font-style: italic;
+  margin: 0 0 .8em;
+}
+
+table {
+  margin-bottom: 2em;
+  border-bottom: 1px solid #ddd;
+  border-right: 1px solid #ddd;
+  border-spacing: 0;
+  border-collapse: collapse;
+}
+
+table th {
+  padding: .2em 1em;
+  background-color: #eee;
+  border-top: 1px solid #ddd;
+  border-left: 1px solid #ddd;
+}
+
+table td {
+  padding: .2em 1em;
+  border-top: 1px solid #ddd;
+  border-left: 1px solid #ddd;
+  vertical-align: top;
+}
+
+table tr.even {
+  background-color: #fbfbfb;
+}
+
+.author {
+  font-size: 1.2em;
+  text-align: center;
+}
+
+@media only screen and (min-width: 480px) {
+  body {
+    font-size: 14px;
+  }
+}
+@media only screen and (min-width: 768px) {
+  body {
+    font-size: 16px;
+  }
+}
+@media print {
+  * {
+    background: transparent !important;
+    color: black !important;
+    filter: none !important;
+    -ms-filter: none !important;
+  }
+
+  body {
+    font-size: 12pt;
+    max-width: 100%;
+  }
+
+  a, a:visited {
+    text-decoration: underline;
+  }
+
+  hr {
+    height: 1px;
+    border: 0;
+    border-bottom: 1px solid black;
+  }
+
+  a[href]:after {
+    content: " (" attr(href) ")";
+  }
+
+  abbr[title]:after {
+    content: " (" attr(title) ")";
+  }
+
+  .ir a:after, a[href^="javascript:"]:after, a[href^="#"]:after {
+    content: "";
+  }
+
+  pre, blockquote {
+    border: 1px solid #999;
+    padding-right: 1em;
+    page-break-inside: avoid;
+  }
+
+  tr, img {
+    page-break-inside: avoid;
+  }
+
+  img {
+    max-width: 100% !important;
+  }
+
+  @page :left {
+    margin: 15mm 20mm 15mm 10mm;
+}
+
+  @page :right {
+    margin: 15mm 10mm 15mm 20mm;
+}
+
+  p, h2, h3 {
+    orphans: 3;
+    widows: 3;
+  }
+
+  h2, h3 {
+    page-break-after: avoid;
+  }
+}
diff --git a/cabal-plan/src-exe/LicenseReport.hs b/cabal-plan/src-exe/LicenseReport.hs
new file mode 100644
index 0000000..9427d7a
--- /dev/null
+++ b/cabal-plan/src-exe/LicenseReport.hs
@@ -0,0 +1,271 @@
+{-# LANGUAGE CPP               #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RecordWildCards   #-}
+
+-- | Implements @cabal-plan license-report@ functionality
+module LicenseReport
+    ( generateLicenseReport
+    ) where
+
+#if defined(MIN_VERSION_Cabal)
+import           Cabal.Plan
+import qualified Codec.Archive.Tar                      as Tar
+import qualified Codec.Archive.Tar.Entry                as Tar
+import qualified Codec.Compression.GZip                 as GZip
+import           Control.Monad.Compat                   (forM, forM_, guard, unless, when)
+import qualified Data.ByteString.Lazy                   as BSL
+import qualified Data.ByteString                        as BS
+import           Data.Map                               (Map)
+import           Data.List                              (nub)
+import qualified Data.Map                               as Map
+import           Data.Semigroup
+import           Data.Set                               (Set)
+import qualified Data.Set                               as Set
+import qualified Data.Text                              as T
+import qualified Data.Text.IO                           as T
+import qualified Data.Version                           as DV
+import           Distribution.PackageDescription
+import           Distribution.PackageDescription.Parsec
+import           Distribution.Pretty
+import           System.Directory
+import           System.FilePath
+import           System.IO                              (stderr)
+import           Text.ParserCombinators.ReadP
+import           Prelude ()
+import           Prelude.Compat
+
+-- | Read tarball lazily (and possibly decompress)
+readTarEntries :: FilePath -> IO [Tar.Entry]
+readTarEntries idxtar = do
+    es <- case takeExtension idxtar of
+            ".gz"  -> Tar.read . GZip.decompress <$> BSL.readFile idxtar
+            ".tar" -> Tar.read                   <$> BSL.readFile idxtar
+            ext    -> error ("unknown extension " ++ show ext)
+
+    return (Tar.foldEntries (:) [] (\err -> error ("readTarEntries " ++ show err)) es)
+
+fp2pid :: FilePath -> Maybe PkgId
+fp2pid fn0 = do
+  [pns,pvs,rest] <- Just (splitDirectories fn0)
+  guard (rest == pns <.> "cabal")
+  pv <- parseVer pvs
+  pure (PkgId (PkgName $ T.pack pns) pv)
+
+
+parseVer :: String -> Maybe Ver
+parseVer str = case reverse $ readP_to_S DV.parseVersion str of
+  (ver, "") : _ | not (null (DV.versionBranch ver)), all (>= 0) (DV.versionBranch ver)
+      -> Just (Ver $ DV.versionBranch ver)
+  _   -> Nothing
+
+
+readHackageIndex :: IO [(PkgId, BSL.ByteString)]
+readHackageIndex = do
+    -- TODO: expose package index configuration as CLI flag
+    cabalPkgCacheDir <- getAppUserDataDirectory "cabal/packages/hackage.haskell.org"
+    ents <- readTarEntries (cabalPkgCacheDir </> "01-index.tar")
+
+    pure [ (maybe (error $ show n) id $ fp2pid n,bsl)
+         | e@(Tar.Entry { Tar.entryContent = Tar.NormalFile bsl _ }) <- ents
+         , let n = Tar.entryPath e
+         , takeExtension n == ".cabal"
+         ]
+
+getLicenseFiles :: PkgId -> UnitId -> [FilePath] -> IO [BS.ByteString]
+getLicenseFiles compilerId (UnitId uidt) fns = do
+  storeDir <- getAppUserDataDirectory "cabal/store"
+  let docDir = storeDir </> T.unpack (dispPkgId compilerId) </> T.unpack uidt </> "share" </> "doc"
+  forM fns $ \fn -> BS.readFile (docDir </> fn)
+
+{- WARNING: the code that follows will make you cry; a safety pig is provided below for your benefit.
+
+                         _
+ _._ _..._ .-',     _.._(`))
+'-. `     '  /-._.-'    ',/
+   )         \            '.
+  / _    _    |             \
+ |  a    a    /              |
+ \   .-.                     ;
+  '-('' ).-'       ,'       ;
+     '-;           |      .'
+        \           \    /
+        | 7  .__  _.-\   \
+        | |  |  ``/  /`  /
+       /,_|  |   /,_/   /
+          /,_/      '`-'
+
+-}
+
+-- TODO: emit report to Text or Text builder
+generateLicenseReport :: Maybe FilePath -> PlanJson -> UnitId -> CompName -> IO ()
+generateLicenseReport mlicdir plan uid0 cn0 = do
+    let pidsOfInterest = Set.fromList (map uPId (Map.elems $ pjUnits plan))
+
+    indexDb <- Map.fromList . filter (flip Set.member pidsOfInterest . fst) <$> readHackageIndex
+
+    let -- generally, units belonging to the same package as 'root'
+        rootPkgUnits = [ u | u@(Unit { uPId = PkgId pn' _ }) <- Map.elems (pjUnits plan), pn' == pn0 ]
+        rootPkgUnitIds = Set.fromList (map uId rootPkgUnits)
+
+        -- the component of interest
+        Just root@Unit { uPId = PkgId pn0 _ } = Map.lookup uid0 (pjUnits plan)
+
+        fwdDeps = planJsonIdGraph' plan
+        revDeps = invertMap fwdDeps
+
+    let transUids = transDeps fwdDeps (uId root) Set.\\ rootPkgUnitIds
+
+        indirectDeps = Set.fromList [ u | u <- Set.toList transUids, Set.null (Map.findWithDefault mempty u revDeps `Set.intersection` rootPkgUnitIds) ]
+
+        directDeps = transUids Set.\\ indirectDeps
+
+
+    let printInfo :: UnitId -> IO ()
+        printInfo uid = do
+          let Just u = Map.lookup uid (pjUnits plan)
+
+              PkgId (PkgName pn) pv = uPId u
+
+          case BSL.toStrict <$> Map.lookup (uPId u) indexDb of
+            Nothing
+              | PkgId (PkgName "rts") _ <- uPId u -> pure ()
+              | otherwise -> fail (show u)
+
+            Just x -> do
+              gpd <- maybe (fail "parseGenericPackageDescriptionMaybe") pure $
+                     parseGenericPackageDescriptionMaybe x
+
+              let desc = escapeDesc $ synopsis $ packageDescription gpd
+                  lic  = license  $ packageDescription gpd
+                  -- cr   = copyright $ packageDescription gpd
+                  lfs  = licenseFiles $ packageDescription gpd
+
+                  usedBy = Set.fromList [ uPId (Map.findWithDefault undefined unit (pjUnits plan))
+                                        | unit <- Set.toList (Map.findWithDefault mempty uid revDeps)
+                                        , unit `Set.member` (directDeps <> indirectDeps)
+                                        ]
+
+              let url = "http://hackage.haskell.org/package/" <> dispPkgId (uPId u)
+
+                  isB = uType u == UnitTypeBuiltin
+
+                  -- special core libs whose reverse deps are too noisy
+                  baseLibs = ["base", "ghc-prim", "integer-gmp", "integer-simple", "rts"]
+
+                  licurl = case lfs of
+                             [] -> url
+                             (l:_)
+                               | Just licdir <- mlicdir, uType u == UnitTypeGlobal -> T.pack (licdir </> T.unpack (dispPkgId (uPId u)) </> takeFileName l)
+                               | otherwise              -> url <> "/src/" <> T.pack l
+
+              T.putStrLn $ mconcat
+                [ if isB then "| **`" else "| `", pn, if isB then "`** | [`" else "` | [`", dispVer pv, "`](", url , ")", " | "
+                , "[`", T.pack (prettyShow lic), "`](", licurl , ")", " | "
+                , T.pack desc, " | "
+                , if pn `elem` baseLibs then "*(core library)*"
+                  else T.intercalate ", " [ T.singleton '`' <> (j :: T.Text) <> "`" | PkgId (z@(PkgName j)) _ <- Set.toList usedBy,  z /= pn0], " |"
+                ]
+
+              -- print (pn, pv, prettyShow lic, cr, lfs, [ j | PkgId (PkgName j) _ <- Set.toList usedBy ])
+
+              forM_ mlicdir $ \licdir -> do
+
+                case uType u of
+                  UnitTypeGlobal -> do
+                    let lfs' = nub (map takeFileName lfs)
+
+                    when (length lfs' /= length lfs) $ do
+                      T.hPutStrLn stderr ("WARNING: Overlapping license filenames for " <> dispPkgId (uPId u))
+
+                    crdat <- getLicenseFiles (pjCompilerId plan) uid lfs'
+
+                    forM_ (zip lfs' crdat) $ \(fn,txt) -> do
+                      let d = licdir </> T.unpack (dispPkgId (uPId u))
+                      createDirectoryIfMissing True d
+                      BS.writeFile (d </> fn) txt
+
+                    -- forM_ crdat $ print
+                    pure ()
+
+                  -- TODO:
+                  --   UnitTypeBuiltin
+                  --   UnitTypeLocal
+                  --   UnitTypeInplace
+
+                  UnitTypeBuiltin -> T.hPutStrLn stderr ("WARNING: license files for " <> dispPkgId (uPId u) <> " (global/GHC bundled) not copied")
+                  UnitTypeLocal   -> T.hPutStrLn stderr ("WARNING: license files for " <> dispPkgId (uPId u) <> " (project-local package) not copied")
+                  UnitTypeInplace -> T.hPutStrLn stderr ("WARNING: license files for " <> dispPkgId (uPId u) <> " (project-inplace package) not copied")
+
+                unless (length lfs == Set.size (Set.fromList lfs)) $
+                  fail ("internal invariant broken for " <> show (uPId u))
+
+          pure ()
+
+    T.putStrLn "# Dependency License Report"
+    T.putStrLn ""
+    T.putStrLn ("Bold-faced **`package-name`**s denote standard libraries bundled with `" <> dispPkgId (pjCompilerId plan) <> "`.")
+    T.putStrLn ""
+
+    T.putStrLn ("## Direct dependencies of `" <> unPkgN pn0 <> ":" <> dispCompName cn0 <> "`")
+    T.putStrLn ""
+    T.putStrLn "| Name | Version | [SPDX](https://spdx.org/licenses/) License Id | Description | Also depended upon by |"
+    T.putStrLn "| --- | --- | --- | --- | --- |"
+    forM_ directDeps $ printInfo
+    T.putStrLn ""
+
+    T.putStrLn "## Indirect transitive dependencies"
+    T.putStrLn ""
+    T.putStrLn "| Name | Version | [SPDX](https://spdx.org/licenses/) License Id | Description | Depended upon by |"
+    T.putStrLn "| --- | --- | --- | --- | --- |"
+    forM_ indirectDeps $ printInfo
+    T.putStrLn ""
+
+    pure ()
+
+escapeDesc :: String -> String
+escapeDesc []          = []
+escapeDesc ('\n':rest) = ' ':escapeDesc rest
+escapeDesc ('|':rest)  = '\\':'|':escapeDesc rest
+escapeDesc (x:xs)      = x:escapeDesc xs
+
+unPkgN :: PkgName -> T.Text
+unPkgN (PkgName t) = t
+
+planItemAllLibDeps :: Unit -> Set.Set UnitId
+planItemAllLibDeps Unit{..} = mconcat [ ciLibDeps | (cn,CompInfo{..}) <- Map.toList uComps, wantC cn ]
+  where
+    wantC (CompNameSetup)   = False
+    wantC (CompNameTest _)  = False
+    wantC (CompNameBench _) = False
+    wantC _                 = True
+
+planJsonIdGraph':: PlanJson -> Map UnitId (Set UnitId)
+planJsonIdGraph' PlanJson{..} = Map.fromList [ (uId unit, planItemAllLibDeps unit) | unit <- Map.elems pjUnits ]
+
+
+
+invertMap :: Ord k => Map k (Set k) -> Map k (Set k)
+invertMap m0 = Map.fromListWith mappend [ (v, Set.singleton k) | (k,vs) <- Map.toList m0, v <- Set.toList vs ]
+
+transDeps :: Map UnitId (Set UnitId) -> UnitId -> Set UnitId
+transDeps g n0 = go mempty [n0]
+  where
+    go :: Set UnitId -> [UnitId] -> Set UnitId
+    go acc [] = acc
+    go acc (n:ns)
+      | Set.member n acc = go acc ns
+      | otherwise = go (Set.insert n acc) (ns ++ Set.toList (Map.findWithDefault undefined n g))
+
+#else
+
+----------------------------------------------------------------------------
+import           Cabal.Plan
+import           System.Exit
+import           System.IO
+
+generateLicenseReport :: Maybe FilePath -> PlanJson -> UnitId -> CompName -> IO ()
+generateLicenseReport _ _ _ _ = do
+  hPutStrLn stderr "ERROR: `cabal-plan license-report` sub-command not available! Please recompile/reinstall `cabal-plan` with the `license-report` Cabal flag activated."
+  exitFailure
+
+#endif
diff --git a/cabal-plan/src-exe/cabal-plan.hs b/cabal-plan/src-exe/cabal-plan.hs
new file mode 100644
index 0000000..2da2519
--- /dev/null
+++ b/cabal-plan/src-exe/cabal-plan.hs
@@ -0,0 +1,855 @@
+{-# LANGUAGE CPP               #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RecordWildCards   #-}
+
+module Main where
+
+import           Prelude                     ()
+import           Prelude.Compat
+
+import           Control.Monad.Compat        (forM_, guard, unless, when)
+import           Control.Monad.RWS.Strict    (RWS, evalRWS, gets, modify', tell)
+import           Control.Monad.ST            (runST)
+import           Data.Char                   (isAlphaNum)
+import           Data.Foldable               (for_, toList)
+import qualified Data.Graph                  as G
+import           Data.Map                    (Map)
+import qualified Data.Map                    as M
+import           Data.Maybe                  (fromMaybe, isJust, mapMaybe)
+import           Data.Monoid                 (Any (..))
+import           Data.Semigroup              (Semigroup (..))
+import           Data.Set                    (Set)
+import qualified Data.Set                    as S
+import qualified Data.Text                   as T
+import qualified Data.Text.IO                as T
+import qualified Data.Text.Lazy              as LT
+import qualified Data.Text.Lazy.Builder      as LT
+import qualified Data.Text.Lazy.IO           as LT
+import qualified Data.Tree                   as Tr
+import           Data.Tuple                  (swap)
+import qualified Data.Vector.Unboxed         as U
+import qualified Data.Vector.Unboxed.Mutable as MU
+import           Data.Version
+import           Options.Applicative
+import           System.Console.ANSI
+import           System.Directory            (getCurrentDirectory)
+import           System.Exit                 (exitFailure)
+import           System.IO                   (hPutStrLn, stderr)
+import qualified Text.Parsec                 as P
+import qualified Text.Parsec.String          as P
+import qualified Topograph                   as TG
+
+import           Cabal.Plan
+import           LicenseReport               (generateLicenseReport)
+import           Paths_cabal_plan            (version)
+
+haveUnderlineSupport :: Bool
+#if defined(UNDERLINE_SUPPORT)
+haveUnderlineSupport = True
+#else
+haveUnderlineSupport = False
+#endif
+
+data GlobalOptions = GlobalOptions
+    { buildDir        :: Maybe FilePath
+    , optsShowBuiltin :: Bool
+    , optsShowGlobal  :: Bool
+    , cmd             :: Command
+    }
+
+data Command
+    = InfoCommand
+    | ShowCommand
+    | FingerprintCommand
+    | ListBinsCommand MatchCount [Pattern]
+    | DotCommand Bool Bool [Highlight]
+    | TopoCommand Bool
+    | LicenseReport (Maybe FilePath) Pattern
+
+-------------------------------------------------------------------------------
+-- Pattern
+-------------------------------------------------------------------------------
+
+-- | patterns are @[[pkg:]kind;]cname@
+data Pattern = Pattern (Maybe T.Text) (Maybe CompType) (Maybe T.Text)
+    deriving (Show, Eq)
+
+data CompType = CompTypeLib | CompTypeFLib | CompTypeExe | CompTypeTest | CompTypeBench | CompTypeSetup
+    deriving (Show, Eq, Enum, Bounded)
+
+parsePattern :: String -> Either String Pattern
+parsePattern = either (Left . show) Right . P.runParser (patternP <* P.eof) () "<argument>"
+  where
+    patternP = do
+        -- first we parse up to 3 tokens
+        x <- tokenP
+        y <- optional $ do
+            _ <- P.char ':'
+            y <- tokenP
+            z <- optional $ P.char ':' >> tokenP
+            return (y, z)
+        -- then depending on how many tokens we got, we make a pattern
+        case y of
+            Nothing -> return $ Pattern Nothing Nothing x
+            Just (y', Nothing) -> do
+                t <- traverse toCompType x
+                return $ Pattern Nothing t y'
+            Just (y', Just z') -> do
+                t <-  traverse toCompType y'
+                return $ Pattern x t z'
+
+    tokenP :: P.Parser (Maybe T.Text)
+    tokenP =
+        Nothing <$ P.string "*"
+        <|> (Just . T.pack <$> some (P.satisfy (\c -> isAlphaNum c || c `elem` ("-_" :: String))) P.<?> "part of pattern")
+
+    toCompType :: T.Text -> P.Parser CompType
+    toCompType "bench" = return $ CompTypeBench
+    toCompType "exe"   = return $ CompTypeExe
+    toCompType "lib"   = return $ CompTypeLib
+    toCompType "flib"  = return $ CompTypeFLib
+    toCompType "setup" = return $ CompTypeSetup
+    toCompType "test"  = return $ CompTypeTest
+    toCompType t       = fail $ "Unknown component type: " ++ show t
+
+patternCompleter :: Bool -> Completer
+patternCompleter onlyWithExes = mkCompleter $ \pfx -> do
+    plan <- getCurrentDirectory >>= findAndDecodePlanJson . ProjectRelativeToDir
+    let tpfx  = T.pack pfx
+        components = findComponents plan
+
+    -- One scenario
+    -- $ cabal-plan list-bin cab<TAB>
+    -- $ cabal-plan list-bin cabal-plan<TAB>
+    -- $ cabal-plan list-bin cabal-plan:exe:cabal-plan
+    --
+    -- Note: if this package had `tests` -suite, then we can
+    -- $ cabal-plan list-bin te<TAB>
+    -- $ cabal-plan list-bin tests<TAB>
+    -- $ cabal-plan list-bin cabal-plan:test:tests
+    --
+    -- *BUT* at least zsh script have to be changed to complete from non-prefix.
+    return $ map T.unpack $ firstNonEmpty
+        -- 1. if tpfx matches component exacty, return full path
+        [ single $ map fst $ filter ((tpfx ==) . snd) components
+
+        -- 2. match component parts
+        , uniques $ filter (T.isPrefixOf tpfx) $ map snd components
+
+        -- otherwise match full paths
+        , filter (T.isPrefixOf tpfx) $ map fst components
+        ]
+  where
+    firstNonEmpty :: [[a]] -> [a]
+    firstNonEmpty []         = []
+    firstNonEmpty ([] : xss) = firstNonEmpty xss
+    firstNonEmpty (xs : _)   = xs
+
+    -- single
+    single :: [a] -> [a]
+    single xs@[_] = xs
+    single _      = []
+
+    -- somewhat like 'nub' but drop duplicate names. Doesn't preserve order
+    uniques :: Ord a => [a] -> [a]
+    uniques = M.keys . M.filter (== 1) . M.fromListWith (+) . map (\x -> (x, 1 :: Int))
+
+    impl :: Bool -> Bool -> Bool
+    impl False _ = True
+    impl True  x = x
+
+    -- returns (full, cname) pair
+    findComponents :: PlanJson -> [(T.Text, T.Text)]
+    findComponents plan = do
+        (_, Unit{..}) <- M.toList $ pjUnits plan
+        (cn, ci) <- M.toList $ uComps
+
+        -- if onlyWithExes, component should have binFile
+        guard (onlyWithExes `impl` isJust (ciBinFile ci))
+
+        let PkgId pn@(PkgName pnT) _ = uPId
+            g = case cn of
+                CompNameLib -> pnT <> T.pack":lib:" <> pnT
+                _           -> pnT <> T.pack":" <> dispCompName cn
+
+        let cnT = extractCompName pn cn
+        [ (g, cnT) ]
+
+compNameType :: CompName -> CompType
+compNameType CompNameLib        = CompTypeLib
+compNameType (CompNameSubLib _) = CompTypeLib
+compNameType (CompNameFLib _)   = CompTypeFLib
+compNameType (CompNameExe _)    = CompTypeExe
+compNameType (CompNameTest _)   = CompTypeTest
+compNameType (CompNameBench _)  = CompTypeBench
+compNameType CompNameSetup      = CompTypeSetup
+
+checkPattern :: Pattern -> PkgName -> CompName -> Any
+checkPattern (Pattern n k c) pn cn =
+    Any $ nCheck && kCheck && cCheck
+  where
+    nCheck = case n of
+        Nothing  -> True
+        Just pn' -> pn == PkgName pn'
+
+    kCheck = case k of
+        Nothing -> True
+        Just k' -> k' == compNameType cn
+    cCheck = case c of
+        Nothing -> True
+        Just c' -> c' == extractCompName pn cn
+
+extractCompName :: PkgName -> CompName -> T.Text
+extractCompName (PkgName pn) CompNameLib         = pn
+extractCompName (PkgName pn) CompNameSetup       = pn
+extractCompName _            (CompNameSubLib cn) = cn
+extractCompName _            (CompNameFLib cn)   = cn
+extractCompName _            (CompNameExe cn)    = cn
+extractCompName _            (CompNameTest cn)   = cn
+extractCompName _            (CompNameBench cn)  = cn
+
+-------------------------------------------------------------------------------
+-- Highlight
+-------------------------------------------------------------------------------
+
+data Highlight
+    = Path Pattern Pattern
+    | Revdep Pattern
+    deriving (Show, Eq)
+
+highlightParser :: Parser Highlight
+highlightParser = pathParser <|> revdepParser
+  where
+    pathParser = Path
+        <$> option (eitherReader parsePattern)
+            (long "path-from" <> metavar "PATTERN" <> help "Highlight dependency paths from ...")
+        <*> option (eitherReader parsePattern)
+            (long "path-to" <> metavar "PATTERN")
+
+    revdepParser = Revdep
+        <$> option (eitherReader parsePattern)
+            (long "revdep" <> metavar "PATTERN" <> help "Highlight reverse dependencies")
+
+-------------------------------------------------------------------------------
+-- Main
+-------------------------------------------------------------------------------
+
+main :: IO ()
+main = do
+    GlobalOptions{..} <- execParser $ info (helper <*> optVersion <*> optParser) fullDesc
+    (searchMethod, mProjRoot) <- case buildDir of
+            Just dir -> pure (InBuildDir dir, Nothing)
+            Nothing -> do
+                cwd <- getCurrentDirectory
+                root <- findProjectRoot cwd
+                pure (ProjectRelativeToDir cwd, root)
+
+    plan <- findAndDecodePlanJson searchMethod
+    case cmd of
+      InfoCommand -> doInfo mProjRoot plan
+      ShowCommand -> mapM_ print mProjRoot >> print plan
+      ListBinsCommand count pats -> do
+          let bins = doListBin plan pats
+          case (count, bins) of
+              (MatchMany, _) -> for_ bins $ \(g, fn) ->
+                    putStrLn (g ++ "  " ++ fn)
+              (MatchOne, [(_,p)]) -> putStrLn p
+              (MatchOne, []) -> do
+                 hPutStrLn stderr "No matches found."
+                 exitFailure
+              (MatchOne, _) -> do
+                 hPutStrLn stderr "Found more than one matching pattern:"
+                 for_ bins $ \(p,_) -> hPutStrLn stderr $ "  " ++ p
+                 exitFailure
+      FingerprintCommand -> doFingerprint plan
+      DotCommand tred tredWeights highlights -> doDot optsShowBuiltin optsShowGlobal plan tred tredWeights highlights
+      TopoCommand rev -> doTopo optsShowBuiltin optsShowGlobal plan rev
+      LicenseReport mfp pat -> doLicenseReport mfp pat
+  where
+    optVersion = infoOption ("cabal-plan " ++ showVersion version)
+                            (long "version" <> help "output version information and exit")
+
+    optParser = GlobalOptions
+        <$> dirParser
+        <*> showHide "builtin" "Show / hide packages in global (non-nix-style) package db"
+        <*> showHide "global" "Show / hide packages in nix-store"
+        <*> (cmdParser <|> defaultCommand)
+
+    showHide n d =
+        flag' True (long ("show-" ++ n) <> help d)
+        <|> flag' False (long ("hide-" ++ n))
+        <|> pure True
+
+    dirParser = optional . strOption $ mconcat
+        [ long "builddir", metavar "DIR"
+        , help "Build directory to read plan.json from." ]
+
+    subCommand name desc val = command name $ info val (progDesc desc)
+
+    patternParser = argument (eitherReader parsePattern) . mconcat
+
+    switchM = switch . mconcat
+
+    cmdParser = subparser $ mconcat
+        [ subCommand "info" "Info" $ pure InfoCommand
+        , subCommand "show" "Show" $ pure ShowCommand
+        , subCommand "list-bins" "List All Binaries" .
+            listBinParser MatchMany . many $ patternParser
+                [ metavar "PATTERNS...", help "Patterns to match.", completer $ patternCompleter True ]
+        , subCommand "list-bin" "List Single Binary" .
+            listBinParser MatchOne $ pure <$> patternParser
+                [ metavar "PATTERN", help "Pattern to match.", completer $ patternCompleter True ]
+        , subCommand "fingerprint" "Fingerprint" $ pure FingerprintCommand
+        , subCommand "dot" "Dependency .dot" $ DotCommand
+              <$> switchM
+                  [ long "tred", help "Transitive reduction" ]
+              <*> switchM
+                  [ long "tred-weights", help "Adjust edge thickness during transitive reduction" ]
+              <*> many highlightParser
+              <**> helper
+        , subCommand "topo" "Plan in a topological sort" $ TopoCommand
+              <$> switchM
+                  [ long "reverse", help "Reverse order" ]
+              <**> helper
+        , subCommand "license-report" "Generate license report for a component" $ LicenseReport
+              <$> optional (strOption $ mconcat [ long "licensedir", metavar "DIR", help "Write per-package license documents to folder" ])
+              <*> patternParser
+                  [ metavar "PATTERN", help "Pattern to match.", completer $ patternCompleter False ]
+              <**> helper
+        ]
+
+    defaultCommand = pure InfoCommand
+
+-------------------------------------------------------------------------------
+-- list-bin
+-------------------------------------------------------------------------------
+
+listBinParser
+    :: MatchCount
+    -> Parser [Pattern]
+    -> Parser Command
+listBinParser count pats
+    = ListBinsCommand count <$> pats <**> helper
+data MatchCount = MatchOne | MatchMany
+    deriving (Show, Eq)
+
+doListBin :: PlanJson -> [Pattern] -> [(String, FilePath)]
+doListBin plan patterns = do
+    (_, Unit{..}) <- M.toList $ pjUnits plan
+    (cn, ci) <- M.toList $ uComps
+    case ciBinFile ci of
+        Nothing -> []
+        Just fn -> do
+            let PkgId pn@(PkgName pnT) _ = uPId
+                g = case cn of
+                    CompNameLib -> T.unpack (pnT <> T.pack":lib:" <> pnT)
+                    _           -> T.unpack (pnT <> T.pack":" <> dispCompName cn)
+            guard . getAny $ patternChecker pn cn
+            [(g, fn)]
+  where
+    patternChecker :: PkgName -> CompName -> Any
+    patternChecker = case patterns of
+        [] -> \_ _ -> Any True
+        _  -> mconcat $ map checkPattern patterns
+
+-------------------------------------------------------------------------------
+-- fingerprint
+-------------------------------------------------------------------------------
+
+doFingerprint :: PlanJson -> IO ()
+doFingerprint plan = do
+    let pids = M.fromList [ (uPId u, u) | (_,u) <- M.toList (pjUnits plan) ]
+
+    for_ (M.toList pids) $ \(_,Unit{..}) -> do
+        let h = maybe "________________________________________________________________"
+                      dispSha256 $ uSha256
+        case uType of
+          UnitTypeBuiltin -> T.putStrLn (h <> " B " <> dispPkgId uPId)
+          UnitTypeGlobal  -> T.putStrLn (h <> " G " <> dispPkgId uPId)
+          UnitTypeLocal   -> T.putStrLn (h <> " L " <> dispPkgId uPId)
+          UnitTypeInplace -> T.putStrLn (h <> " I " <> dispPkgId uPId)
+
+-------------------------------------------------------------------------------
+-- info
+-------------------------------------------------------------------------------
+
+doInfo :: Maybe FilePath -> PlanJson -> IO ()
+doInfo mProjbase plan = do
+    forM_ mProjbase $ \projbase ->
+        putStrLn ("using '" ++ projbase ++ "' as project root")
+    putStrLn ""
+    putStrLn "Tree"
+    putStrLn "~~~~"
+    putStrLn ""
+    LT.putStrLn (dumpPlanJson plan)
+
+    -- print (findCycles (planJsonIdGrap v))
+
+    putStrLn ""
+    putStrLn "Top-sorted"
+    putStrLn "~~~~~~~~~~"
+    putStrLn ""
+
+    let xs = toposort (planJsonIdGraph plan)
+    for_ xs print
+
+    putStrLn ""
+    putStrLn "Direct deps"
+    putStrLn "~~~~~~~~~~~"
+    putStrLn ""
+
+    let locals = [ Unit{..} | Unit{..} <- M.elems pm, uType == UnitTypeLocal ]
+        pm = pjUnits plan
+
+    for_ locals $ \pitem -> do
+        print (uPId pitem)
+        for_ (M.toList $ uComps pitem) $ \(ct,ci) -> do
+            print ct
+            for_ (S.toList $ ciLibDeps ci) $ \dep -> do
+                let Just dep' = M.lookup dep pm
+                    pid = uPId dep'
+                putStrLn ("  " ++ T.unpack (dispPkgId pid))
+            putStrLn ""
+
+    return ()
+
+-------------------------------------------------------------------------------
+-- Dot
+-------------------------------------------------------------------------------
+
+-- | vertex of dot graph.
+--
+-- if @'Maybe' 'CompName'@ is Nothing, this is legacy, multi-component unit.
+data DotUnitId = DU UnitId (Maybe CompName)
+    deriving (Eq, Ord, Show)
+
+planJsonDotUnitGraph :: PlanJson -> Map DotUnitId (Set DotUnitId)
+planJsonDotUnitGraph plan = M.fromList $ do
+    unit <- M.elems units
+    let mkDU = DU (uId unit)
+    let mkDeps cname ci = (mkDU (Just cname), deps ci)
+    case M.toList (uComps unit) of
+        [(cname, ci)] ->
+            [ mkDeps cname ci ]
+        cs            ->
+            [ (mkDU Nothing, S.fromList $ map (mkDU . Just . fst) cs) ]
+            ++ map (uncurry mkDeps) cs
+  where
+    units = pjUnits plan
+
+    unitToDot :: Unit -> DotUnitId
+    unitToDot unit = DU (uId unit) $ case M.toList (uComps unit) of
+        [(cname, _)] -> Just cname
+        _            -> Nothing
+
+    unitIdToDot :: UnitId -> Maybe DotUnitId
+    unitIdToDot i = unitToDot <$> M.lookup i units
+
+    deps :: CompInfo -> Set DotUnitId
+    deps CompInfo{..} =
+        S.fromList $ mapMaybe unitIdToDot $ S.toList $ ciLibDeps <> ciExeDeps
+
+-- | Tree which counts paths under it.
+data Tr a = No !Int a [Tr a]
+  deriving (Show)
+
+trPaths :: Tr a -> Int
+trPaths (No n _ _) = n
+
+-- | Create 'Tr' maintaining the invariant
+mkNo :: a -> [Tr a] -> Tr a
+mkNo x [] = No 1 x []
+mkNo x xs = No (sum $ map trPaths xs) x xs
+
+trFromTree :: Tr.Tree a -> Tr a
+trFromTree (Tr.Node i is) = mkNo i (map trFromTree is)
+
+trPairs :: Tr a -> [(Int,a,a)]
+trPairs (No _ i js) =
+    [ (n, i, j) | No n j _ <- js ] ++ concatMap trPairs js
+
+doDot :: Bool -> Bool -> PlanJson -> Bool -> Bool -> [Highlight] -> IO ()
+doDot showBuiltin showGlobal plan tred tredWeights highlights = either loopGraph id $ TG.runG am $ \g' -> do
+    let g = if tred then TG.reduction g' else g'
+
+    -- Highlights
+    let paths :: [(DotUnitId, DotUnitId)]
+        paths = flip concatMap highlights $ \h -> case h of
+            Path a b ->
+                [ (x, y)
+                | x <- filter (getAny . checkPatternDotUnit a) $ toList dotUnits
+                , y <- filter (getAny . checkPatternDotUnit b) $ toList dotUnits
+                ]
+            Revdep _ -> []
+
+    let paths' :: [(DotUnitId, DotUnitId)]
+        paths' = flip concatMap paths $ \(a, b) -> fromMaybe [] $ do
+            i <- TG.gToVertex g a
+            j <- TG.gToVertex g b
+            pure $ concatMap TG.pairs $ (fmap . fmap) (TG.gFromVertex g) (TG.allPaths g i j)
+
+    let revdeps :: [DotUnitId]
+        revdeps = flip concatMap highlights $ \h -> case h of
+            Path _ _ -> []
+            Revdep a -> filter (getAny . checkPatternDotUnit a) $ toList dotUnits
+
+    let tg = TG.transpose g
+
+    let revdeps' :: [(DotUnitId, DotUnitId)]
+        revdeps' = flip concatMap revdeps $ \a -> fromMaybe [] $ do
+            i <- TG.gToVertex tg a
+            pure $ map swap $ TG.treePairs $ fmap (TG.gFromVertex tg) (TG.dfsTree tg i)
+
+    let redVertices :: Set DotUnitId
+        redVertices = foldMap (\(a,b) -> S.fromList [a,b]) $ paths' ++ revdeps'
+
+    let redEdges :: Set (DotUnitId, DotUnitId)
+        redEdges = S.fromList $ paths' ++ revdeps'
+
+    -- Edge weights
+    let weights' :: U.Vector Double
+        weights' = runST $ do
+            let orig = TG.edgesSet g'
+                redu = TG.edgesSet g
+                len  = TG.gVerticeCount g
+            v <- MU.replicate (len * len) (0 :: Double)
+
+            -- for each edge (i, j) in original graph, but not in the reduction
+            for_ (S.difference orig redu) $ \(i, j) -> do
+                -- calculate all paths from i to j, in the reduction
+                for_ (fmap trFromTree $ TG.allPathsTree g i j) $ \ps -> do
+                    -- divide weight across paths
+                    let r  = 1 / fromIntegral (trPaths ps)
+
+                    -- and add that weight to every edge on each path
+                    for_ (trPairs ps) $ \(k, a, b) ->
+                        MU.modify v
+                            (\n -> n + fromIntegral k * r)
+                            (TG.gToInt g b + TG.gToInt g a * len)
+
+            U.freeze v
+
+    let weights :: Map (DotUnitId, DotUnitId) Double
+        weights =
+            if tred && tredWeights
+            then M.fromList
+                [ ((a, b), w + 1)
+                | ((i, j), w) <- zip ((,) <$> TG.gVertices g <*> TG.gVertices g) (U.toList weights')
+                , w > 0
+                , let a = TG.gFromVertex g i
+                , let b = TG.gFromVertex g j
+                ]
+            else M.empty
+
+    -- Beging outputting
+
+    putStrLn "digraph plan {"
+    putStrLn "overlap = false;"
+    putStrLn "rankdir=LR;"
+    putStrLn "node [penwidth=2];"
+
+    -- vertices
+    for_ (TG.gVertices g) $ \i -> vertex redVertices (TG.gFromVertex g i)
+
+    -- edges
+    for_ (TG.gVertices g) $ \i -> for_ (TG.gEdges g i) $ \j ->
+        edge weights redEdges (TG.gFromVertex g i) (TG.gFromVertex g j)
+
+    putStrLn "}"
+  where
+    loopGraph [] = putStrLn "digraph plan {}"
+    loopGraph (u : us) = do
+        putStrLn "digraph plan {"
+        for_ (zip (u : us) (us ++ [u])) $ \(unitA, unitB) ->
+            T.putStrLn $ mconcat
+                [ "\""
+                , dispDotUnit unitA
+                , "\""
+                , " -> "
+                , "\""
+                , dispDotUnit unitB
+                , "\""
+                ]
+        putStrLn "}"
+
+    am = planJsonDotUnitGraph plan
+
+    dotUnits :: Set DotUnitId
+    dotUnits = S.fromList $ M.keys am
+
+    units :: Map UnitId Unit
+    units = pjUnits plan
+
+    duShape :: DotUnitId -> T.Text
+    duShape (DU unitId _) = case M.lookup unitId units of
+        Nothing   -> "oval"
+        Just unit -> case uType unit of
+            UnitTypeBuiltin -> "octagon"
+            UnitTypeGlobal  -> "box"
+            UnitTypeInplace -> "box"
+            UnitTypeLocal   -> "box,style=rounded"
+
+    duShow :: DotUnitId -> Bool
+    duShow (DU unitId _) = case M.lookup unitId units of
+        Nothing -> False
+        Just unit -> case uType unit of
+            UnitTypeBuiltin -> showBuiltin
+            UnitTypeGlobal  -> showGlobal
+            UnitTypeLocal   -> True
+            UnitTypeInplace -> True
+
+    vertex :: Set DotUnitId -> DotUnitId -> IO ()
+    vertex redVertices du = when (duShow du) $ T.putStrLn $ mconcat
+        [ "\""
+        , dispDotUnit du
+        , "\""
+        -- shape
+        , " [shape="
+        , duShape du
+        -- color
+        , ",color="
+        , color
+        , "];"
+        ]
+      where
+        color | S.member du redVertices = "red"
+              | otherwise               = borderColor du
+
+    borderColor :: DotUnitId -> T.Text
+    borderColor (DU _ Nothing)           = "darkviolet"
+    borderColor (DU unitId (Just cname)) = case cname of
+        CompNameLib         -> case M.lookup unitId units of
+            Nothing   -> "black"
+            Just unit -> case uType unit of
+                UnitTypeLocal   -> "blue"
+                UnitTypeInplace -> "blue"
+                _               -> "black"
+        (CompNameSubLib _)  -> "gray"
+        (CompNameFLib _)    -> "darkred"
+        (CompNameExe _)     -> "brown"
+        (CompNameBench _)   -> "darkorange"
+        (CompNameTest _)    -> "darkgreen"
+        CompNameSetup       -> "gold"
+
+    edge
+        :: Map (DotUnitId, DotUnitId) Double
+        -> Set (DotUnitId, DotUnitId)
+        -> DotUnitId -> DotUnitId -> IO ()
+    edge weights redEdges duA duB = when (duShow duA) $ when (duShow duB) $
+        T.putStrLn $ mconcat
+            [ "\""
+            , dispDotUnit duA
+            , "\""
+            , " -> "
+            , "\""
+            , dispDotUnit duB
+            , "\" [color="
+            , color
+            , ",penwidth="
+            , T.pack $ show $ logBase 4 w + 1
+            , ",weight="
+            , T.pack $ show $ logBase 4 w + 1
+            , "];"
+            ]
+      where
+        idPair = (duA, duB)
+
+        color | S.member idPair redEdges = "red"
+              | otherwise                     = borderColor duA
+
+        w = fromMaybe 1 $ M.lookup idPair weights
+
+    checkPatternDotUnit :: Pattern -> DotUnitId -> Any
+    checkPatternDotUnit p (DU unitId mcname) = case M.lookup unitId units of
+        Nothing   -> Any False
+        Just unit -> case mcname of
+            Just cname -> checkPattern p pname cname
+            Nothing    -> foldMap (checkPattern p pname) (M.keys (uComps unit))
+          where
+            PkgId pname _ = uPId unit
+
+    dispDotUnit :: DotUnitId -> T.Text
+    dispDotUnit (DU unitId mcname) = case M.lookup unitId units of
+        Nothing   -> "?"
+        Just unit -> dispPkgId (uPId unit) <> maybe ":*" dispCompName' mcname
+
+    dispCompName' :: CompName -> T.Text
+    dispCompName' CompNameLib = ""
+    dispCompName' cname       = ":" <> dispCompName cname
+
+-------------------------------------------------------------------------------
+-- license-report
+-------------------------------------------------------------------------------
+
+doLicenseReport :: Maybe FilePath -> Pattern -> IO ()
+doLicenseReport mlicdir pat = do
+    plan <- getCurrentDirectory >>= findAndDecodePlanJson . ProjectRelativeToDir
+
+    case findUnit plan of
+      [] -> do
+        hPutStrLn stderr "No matches found."
+        exitFailure
+
+      lst@(_:_:_) -> do
+        hPutStrLn stderr "Multiple matching components found:"
+        forM_ lst $ \(pat', uid, cn) -> do
+          hPutStrLn stderr ("- " ++ T.unpack pat' ++ "   " ++ show (uid, cn))
+        exitFailure
+
+      [(_,uid,cn)] -> generateLicenseReport mlicdir plan uid cn
+
+  where
+    findUnit plan = do
+        (_, Unit{..}) <- M.toList $ pjUnits plan
+        (cn, _) <- M.toList $ uComps
+
+        let PkgId pn@(PkgName pnT) _ = uPId
+            g = case cn of
+                CompNameLib -> pnT <> T.pack":lib:" <> pnT
+                _           -> pnT <> T.pack":" <> dispCompName cn
+
+        guard (getAny $ checkPattern pat pn cn)
+
+        pure (g, uId, cn)
+
+
+-------------------------------------------------------------------------------
+-- topo
+-------------------------------------------------------------------------------
+
+doTopo :: Bool -> Bool -> PlanJson -> Bool -> IO ()
+doTopo showBuiltin showGlobal plan rev = do
+    let units = pjUnits plan
+
+    let topo = TG.runG (planJsonIdGraph plan) $ \TG.G {..} ->
+            map gFromVertex gVertices
+
+    let showUnit unit = case uType unit of
+          UnitTypeBuiltin -> showBuiltin
+          UnitTypeGlobal  -> showGlobal
+          UnitTypeLocal   -> True
+          UnitTypeInplace -> True
+
+    let rev' = if rev then reverse else id
+
+    for_ topo $ \topo' -> for_ (rev' topo') $ \unitId ->
+        for_ (M.lookup unitId units) $ \unit ->
+            when (showUnit unit) $ do
+                let colour = case uType unit of
+                        UnitTypeBuiltin -> Blue
+                        UnitTypeGlobal  -> White
+                        UnitTypeLocal   -> Green
+                        UnitTypeInplace -> Red
+                let components = case M.keys (uComps unit) of
+                        [] -> ""
+                        [CompNameLib] -> ""
+                        names -> " " <> T.intercalate " " (map dispCompName names)
+                putStrLn $
+                    colorify colour (T.unpack $ dispPkgId $ uPId unit)
+                    ++ T.unpack components
+
+----------------------------------------------------------------------------
+
+dumpPlanJson :: PlanJson -> LT.Text
+dumpPlanJson (PlanJson { pjUnits = pm }) = LT.toLazyText out
+  where
+    ((),out) = evalRWS (mapM_ (go2 []) (S.toList roots)) () mempty
+
+    id2pid :: Map UnitId PkgId
+    id2pid = M.fromList [ (uId, uPId) | Unit{..} <- M.elems pm ]
+
+    lupPid uid = M.findWithDefault undefined uid id2pid
+
+    go2 :: [(CompName,Bool)] -> UnitId -> (RWS () LT.Builder (Set UnitId)) ()
+    go2 lvl pid = do
+        pidSeen <- gets (S.member pid)
+
+        let pid_label = if preExists then (prettyId pid) else colorify_ White (prettyId pid)
+
+        if not pidSeen
+         then do
+            tell $ LT.fromString (linepfx ++ pid_label ++ "\n")
+            showDeps
+         else do
+            tell $ LT.fromString (linepfx ++ pid_label ++ ccol CompNameLib " ┄┄\n")
+            -- tell $ LT.fromString (linepfx' ++ " └┄\n")
+
+        modify' (S.insert pid)
+
+        return ()
+      where
+        Just x' = M.lookup pid pm
+
+        preExists = uType x' == UnitTypeBuiltin
+
+        showDeps = for_ (M.toList $ uComps x') $ \(ct,deps) -> do
+            unless (ct == CompNameLib) $
+                tell (LT.fromString $ linepfx' ++ " " ++ prettyCompTy (lupPid pid) ct ++ "\n")
+            for_ (lastAnn $ S.toList (ciLibDeps deps)) $ \(l,y) -> do
+                go2 (lvl ++ [(ct, not l)]) y
+
+
+        linepfx = case unsnoc lvl of
+                         Nothing -> ""
+                         Just (xs,(zt,z)) -> concat [ if x then ccol xt " │ " else "   " | (xt,x) <- xs ]
+                                        ++ (ccol zt $ if z then " ├─ " else " └─ ")
+
+        linepfx' = concat [ if x then  " │ " else "   " | (_,x) <- lvl ]
+
+    roots :: Set UnitId
+    roots = M.keysSet pm `S.difference` leafs
+      where
+        leafs = mconcat $ concatMap (map (ciLibDeps . snd) . M.toList . uComps) (M.elems pm)
+
+    prettyId :: UnitId -> String
+    prettyId = prettyPid . lupPid
+    prettyPid = T.unpack . dispPkgId
+
+    prettyCompTy :: PkgId -> CompName -> String
+    prettyCompTy _pid c@CompNameLib       = ccol c "[lib]"
+    prettyCompTy _pid c@CompNameSetup     = ccol c "[setup]"
+    prettyCompTy pid c@(CompNameExe n)    = ccol c $ "[" ++ prettyPid pid ++ ":exe:"   ++ show n ++ "]"
+    prettyCompTy pid c@(CompNameTest n)   = ccol c $ "[" ++ prettyPid pid ++ ":test:"  ++ show n ++ "]"
+    prettyCompTy pid c@(CompNameBench n)  = ccol c $ "[" ++ prettyPid pid ++ ":bench:" ++ show n ++ "]"
+    prettyCompTy pid c@(CompNameSubLib n) = ccol c $ "[" ++ prettyPid pid ++ ":lib:" ++ show n ++ "]"
+    prettyCompTy pid c@(CompNameFLib n)   = ccol c $ "[" ++ prettyPid pid ++ ":flib:" ++ show n ++ "]"
+
+    ccol CompNameLib        = colorify White
+    ccol (CompNameExe _)    = colorify Green
+    ccol CompNameSetup      = colorify Red
+    ccol (CompNameTest _)   = colorify Yellow
+    ccol (CompNameBench _)  = colorify Cyan
+    ccol (CompNameSubLib _) = colorify Blue
+    ccol (CompNameFLib _)   = colorify Magenta
+
+colorify :: Color -> String -> String
+colorify col s = setSGRCode [SetColor Foreground Vivid col] ++ s ++ setSGRCode [Reset]
+
+colorify_ :: Color -> String -> String
+colorify_ col s
+  | haveUnderlineSupport = setSGRCode [SetUnderlining SingleUnderline, SetColor Foreground Vivid col] ++ s ++ setSGRCode [Reset]
+  | otherwise            = colorify col s
+
+lastAnn :: [x] -> [(Bool,x)]
+lastAnn = reverse . firstAnn . reverse
+
+firstAnn :: [x] -> [(Bool,x)]
+firstAnn []     = []
+firstAnn (x:xs) = (True,x) : map ((,) False) xs
+
+unsnoc :: [x] -> Maybe ([x],x)
+unsnoc [] = Nothing
+unsnoc xs = Just (init xs, last xs)
+
+toposort :: Ord a => Map a (Set a) -> [a]
+toposort m = reverse . map f . G.topSort $ g
+  where
+    (g, f) = graphFromMap m
+
+graphFromMap :: Ord a => Map a (Set a) -> (G.Graph, G.Vertex -> a)
+graphFromMap m = (g, v2k')
+  where
+    v2k' v = case v2k v of ((), k, _) -> k
+
+    (g, v2k, _) = G.graphFromEdges [ ((), k, S.toList v)
+                                   | (k,v) <- M.toList m ]
diff --git a/cabal-plan/src-topograph/LICENSE b/cabal-plan/src-topograph/LICENSE
new file mode 100644
index 0000000..b4696d3
--- /dev/null
+++ b/cabal-plan/src-topograph/LICENSE
@@ -0,0 +1,30 @@
+Copyright (c) 2018, Oleg Grenrus
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Oleg Grenrus nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/cabal-plan/src-topograph/Topograph.hs b/cabal-plan/src-topograph/Topograph.hs
new file mode 100644
index 0000000..13c17a6
--- /dev/null
+++ b/cabal-plan/src-topograph/Topograph.hs
@@ -0,0 +1,527 @@
+{-# LANGUAGE RankNTypes, ScopedTypeVariables, RecordWildCards #-}
+-- | Copyright: (c) 2018, Oleg Grenrus
+-- SPDX-License-Identifier: BSD-3-Clause
+--
+-- Tools to work with Directed Acyclic Graphs,
+-- by taking advantage of topological sorting.
+--
+module Topograph (
+    -- * Graph
+    -- $setup
+
+    G (..),
+    runG,
+    runG',
+    -- * All paths
+    allPaths,
+    allPaths',
+    allPathsTree,
+    -- * DFS
+    dfs,
+    dfsTree,
+    -- * Longest path
+    longestPathLengths,
+    -- * Transpose
+    transpose,
+    -- * Transitive reduction
+    reduction,
+    -- * Transitive closure
+    closure,
+    -- * Query
+    edgesSet,
+    adjacencyMap,
+    adjacencyList,
+    -- * Helper functions
+    treePairs,
+    pairs,
+    getDown,
+    ) where
+
+import           Prelude ()
+import           Prelude.Compat
+import           Data.Orphans ()
+
+import           Control.Monad.ST            (ST, runST)
+import           Data.Maybe                  (fromMaybe, catMaybes, mapMaybe)
+import           Data.Monoid                 (First (..))
+import           Data.List                   (sort)
+import           Data.Foldable               (for_)
+import           Data.Ord                    (Down (..))
+import qualified Data.Graph                  as G
+import           Data.Tree                   as T
+import           Data.Map                    (Map)
+import qualified Data.Map                    as M
+import           Data.Set                    (Set)
+import qualified Data.Set                    as S
+import qualified Data.Vector                 as V
+import qualified Data.Vector.Unboxed         as U
+import qualified Data.Vector.Unboxed.Mutable as MU
+
+import Debug.Trace
+
+-- | Graph representation.
+data G v a = G
+    { gVertices     :: [a]             -- ^ all vertices, in topological order.
+    , gFromVertex   :: a -> v          -- ^ retrieve original vertex data. /O(1)/
+    , gToVertex     :: v -> Maybe a    -- ^ /O(log n)/
+    , gEdges        :: a -> [a]        -- ^ Outgoing edges.
+    , gDiff         :: a -> a -> Int   -- ^ Upper bound of the path length. Negative if there aren't path. /O(1)/
+    , gVerticeCount :: Int
+    , gToInt        :: a -> Int
+    }
+
+-- | Run action on topologically sorted representation of the graph.
+--
+-- === __Examples__
+--
+-- ==== Topological sorting
+--
+-- >>> runG example $ \G {..} -> map gFromVertex gVertices
+-- Right "axbde"
+--
+-- Vertices are sorted
+--
+-- >>> runG example $ \G {..} -> map gFromVertex $ sort gVertices
+-- Right "axbde"
+--
+-- ==== Outgoing edges
+--
+-- >>> runG example $ \G {..} -> map (map gFromVertex . gEdges) gVertices
+-- Right ["xbde","de","d","e",""]
+--
+-- Note: edges are always larger than source vertex:
+--
+-- >>> runG example $ \G {..} -> getAll $ foldMap (\a -> foldMap (\b -> All (a < b)) (gEdges a)) gVertices
+-- Right True
+--
+-- ==== Not DAG
+--
+-- >>> let loop = M.map S.fromList $ M.fromList [('a', "bx"), ('b', "cx"), ('c', "ax"), ('x', "")]
+-- >>> runG loop $ \G {..} -> map gFromVertex gVertices
+-- Left "abc"
+--
+-- >>> runG (M.singleton 'a' (S.singleton 'a')) $ \G {..} -> map gFromVertex gVertices
+-- Left "aa"
+--
+runG
+    :: forall v r. Ord v
+    => Map v (Set v)                    -- ^ Adjacency Map
+    -> (forall i. Ord i => G v i -> r)  -- ^ function on linear indices
+    -> Either [v] r                     -- ^ Return the result or a cycle in the graph.
+runG m f
+    | Just l <- loop = Left (map (indices V.!) l)
+    | otherwise      = Right (f g)
+  where
+    gr :: G.Graph
+    r  :: G.Vertex -> ((), v, [v])
+    _t  :: v -> Maybe G.Vertex
+
+    (gr, r, _t) = G.graphFromEdges [ ((), v, S.toAscList us) | (v, us) <- M.toAscList m ]
+
+    r' :: G.Vertex -> v
+    r' i = case r i of (_, v, _) -> v
+
+    topo :: [G.Vertex]
+    topo = G.topSort gr
+
+    indices :: V.Vector v
+    indices = V.fromList (map r' topo)
+
+    revIndices :: Map v Int
+    revIndices = M.fromList $ zip (map r' topo) [0..]
+
+    edges :: V.Vector [Int]
+    edges = V.map
+        (\v -> maybe
+            []
+            (\sv -> sort $ mapMaybe (\v' -> M.lookup v' revIndices) $ S.toList sv)
+            (M.lookup v m))
+        indices
+
+    -- TODO: let's see if this check is too expensive
+    loop :: Maybe [Int]
+    loop = getFirst $ foldMap (\a -> foldMap (check a) (gEdges g a)) (gVertices g)
+      where
+        check a b
+            | a < b     = First Nothing
+            -- TODO: here we could use shortest path
+            | otherwise = First $ case allPaths g b a of
+                []      -> Nothing
+                (p : _) -> Just p
+
+    g :: G v Int
+    g = G
+        { gVertices     = [0 .. V.length indices - 1]
+        , gFromVertex   = (indices V.!)
+        , gToVertex     = (`M.lookup` revIndices)
+        , gDiff         = \a b -> b - a
+        , gEdges        = (edges V.!)
+        , gVerticeCount = V.length indices
+        , gToInt        = id
+        }
+
+-- | Like 'runG' but returns 'Maybe'
+runG'
+    :: forall v r. Ord v
+    => Map v (Set v)                    -- ^ Adjacency Map
+    -> (forall i. Ord i => G v i -> r)  -- ^ function on linear indices
+    -> Maybe r                          -- ^ Return the result or 'Nothing' if there is a cycle.
+runG' m f = either (const Nothing) Just (runG m f)
+
+-------------------------------------------------------------------------------
+-- All paths
+-------------------------------------------------------------------------------
+
+-- | All paths from @a@ to @b@. Note that every path has at least 2 elements, start and end.
+-- Use 'allPaths'' for the intermediate steps only.
+--
+-- >>> runG example $ \g@G{..} -> fmap3 gFromVertex $ allPaths g <$> gToVertex 'a' <*> gToVertex 'e'
+-- Right (Just ["axde","axe","abde","ade","ae"])
+--
+-- >>> runG example $ \g@G{..} -> fmap3 gFromVertex $ allPaths g <$> gToVertex 'a' <*> gToVertex 'a'
+-- Right (Just [])
+--
+allPaths :: forall v a. Ord a => G v a -> a -> a -> [[a]]
+allPaths g a b = map (\p -> a : p) (allPaths' g a b [b])
+
+-- | 'allPaths' without begin and end elements.
+--
+-- >>> runG example $ \g@G{..} -> fmap3 gFromVertex $ allPaths' g <$> gToVertex 'a' <*> gToVertex 'e' <*> pure []
+-- Right (Just ["xd","x","bd","d",""])
+--
+allPaths' :: forall v a. Ord a => G v a -> a -> a -> [a] -> [[a]]
+allPaths' G {..} a b end = concatMap go (gEdges a) where
+    go :: a -> [[a]]
+    go i
+        | i == b    = [end]
+        | otherwise =
+            let js :: [a]
+                js = filter (<= b) $ gEdges i
+
+                js2b :: [[a]]
+                js2b = concatMap go js
+
+            in map (i:) js2b
+
+
+
+-- | Like 'allPaths' but return a 'T.Tree'.
+--
+-- >>> let t = runG example $ \g@G{..} -> fmap3 gFromVertex $ allPathsTree g <$> gToVertex 'a' <*> gToVertex 'e'
+-- >>> fmap3 (T.foldTree $ \a bs -> if null bs then [[a]] else concatMap (map (a:)) bs) t
+-- Right (Just (Just ["axde","axe","abde","ade","ae"]))
+--
+-- >>> fmap3 (S.fromList . treePairs) t
+-- Right (Just (Just (fromList [('a','b'),('a','d'),('a','e'),('a','x'),('b','d'),('d','e'),('x','d'),('x','e')])))
+--
+-- >>> let ls = runG example $ \g@G{..} -> fmap3 gFromVertex $ allPaths g <$> gToVertex 'a' <*> gToVertex 'e'
+-- >>> fmap2 (S.fromList . concatMap pairs) ls
+-- Right (Just (fromList [('a','b'),('a','d'),('a','e'),('a','x'),('b','d'),('d','e'),('x','d'),('x','e')]))
+--
+-- >>> traverse3_ dispTree t
+-- 'a'
+--   'x'
+--     'd'
+--       'e'
+--     'e'
+--   'b'
+--     'd'
+--       'e'
+--   'd'
+--     'e'
+--   'e'
+--
+-- >>> traverse3_ (putStrLn . T.drawTree . fmap show) t
+-- 'a'
+-- |
+-- +- 'x'
+-- |  |
+-- |  +- 'd'
+-- |  |  |
+-- |  |  `- 'e'
+-- |  |
+-- |  `- 'e'
+-- ...
+--
+allPathsTree :: forall v a. Ord a => G v a -> a -> a -> Maybe (T.Tree a)
+allPathsTree G {..} a b = go a where
+    go :: a -> Maybe (T.Tree a)
+    go i
+        | i == b    = Just (T.Node b [])
+        | otherwise = case mapMaybe go $ filter (<= b) $ gEdges i of
+            [] -> Nothing
+            js -> Just (T.Node i js)
+
+-------------------------------------------------------------------------------
+-- DFS
+-------------------------------------------------------------------------------
+
+-- | Depth-first paths starting at a vertex.
+--
+-- >>> runG example $ \g@G{..} -> fmap3 gFromVertex $ dfs g <$> gToVertex 'x'
+-- Right (Just ["xde","xe"])
+--
+dfs :: forall v a. Ord a => G v a -> a -> [[a]]
+dfs G {..} = go where
+    go :: a -> [[a]]
+    go a = case gEdges a of
+        [] -> [[a]]
+        bs -> concatMap (\b -> map (a :) (go b)) bs
+
+-- | like 'dfs' but returns a 'T.Tree'.
+--
+-- >>> traverse2_ dispTree $ runG example $ \g@G{..} -> fmap2 gFromVertex $ dfsTree g <$> gToVertex 'x'
+-- 'x'
+--   'd'
+--     'e'
+--   'e'
+dfsTree :: forall v a. Ord a => G v a -> a -> T.Tree a
+dfsTree G {..} = go where
+    go :: a -> Tree a
+    go a = case gEdges a of
+        [] -> T.Node a []
+        bs -> T.Node a $ map go bs
+
+-------------------------------------------------------------------------------
+-- Longest / shortest path
+-------------------------------------------------------------------------------
+
+-- | Longest paths lengths starting from a vertex.
+--
+-- >>> runG example $ \g@G{..} -> longestPathLengths g <$> gToVertex 'a'
+-- Right (Just [0,1,1,2,3])
+--
+-- >>> runG example $ \G {..} -> map gFromVertex gVertices
+-- Right "axbde"
+--
+-- >>> runG example $ \g@G{..} -> longestPathLengths g <$> gToVertex 'b'
+-- Right (Just [0,0,0,1,2])
+--
+longestPathLengths :: Ord a => G v a -> a -> [Int]
+longestPathLengths = pathLenghtsImpl max
+
+-- | Shortest paths lengths starting from a vertex.
+--
+-- >>> runG example $ \g@G{..} -> shortestPathLengths g <$> gToVertex 'a'
+-- Right (Just [0,1,1,1,1])
+--
+-- >>> runG example $ \g@G{..} -> shortestPathLengths g <$> gToVertex 'b'
+-- Right (Just [0,0,0,1,2])
+--
+shortestPathLengths :: Ord a => G v a -> a -> [Int]
+shortestPathLengths = pathLenghtsImpl min' where
+    min' 0 y = y
+    min' x y = min x y
+
+pathLenghtsImpl :: forall v a. Ord a => (Int -> Int -> Int) -> G v a -> a -> [Int]
+pathLenghtsImpl merge G {..} a = runST $ do
+    v <- MU.replicate (length gVertices) (0 :: Int)
+    go v (S.singleton a)
+    v' <- U.freeze v
+    pure (U.toList v')
+  where
+    go :: MU.MVector s Int -> Set a -> ST s ()
+    go v xs = do
+        case S.minView xs of
+            Nothing       -> pure ()
+            Just (x, xs') -> do
+                c <- MU.unsafeRead v (gToInt x)
+                let ys = S.fromList $ gEdges x
+                for_ ys $ \y ->
+                    flip (MU.unsafeModify v) (gToInt y) $ \d -> merge d (c + 1)
+                go v (xs' `S.union` ys)
+
+-------------------------------------------------------------------------------
+-- Transpose
+-------------------------------------------------------------------------------
+
+-- | Graph with all edges reversed.
+--
+-- >>> runG example $ adjacencyList . transpose
+-- Right [('a',""),('b',"a"),('d',"abx"),('e',"adx"),('x',"a")]
+--
+-- === __Properties__
+--
+-- Commutes with 'closure'
+--
+-- >>> runG example $ adjacencyList . closure . transpose
+-- Right [('a',""),('b',"a"),('d',"abx"),('e',"abdx"),('x',"a")]
+--
+-- >>> runG example $ adjacencyList . transpose . closure
+-- Right [('a',""),('b',"a"),('d',"abx"),('e',"abdx"),('x',"a")]
+--
+-- Commutes with 'reduction'
+--
+-- >>> runG example $ adjacencyList . reduction . transpose
+-- Right [('a',""),('b',"a"),('d',"bx"),('e',"d"),('x',"a")]
+--
+-- >>> runG example $ adjacencyList . transpose . reduction
+-- Right [('a',""),('b',"a"),('d',"bx"),('e',"d"),('x',"a")]
+--
+transpose :: forall v a. Ord a => G v a -> G v (Down a)
+transpose G {..} = G
+    { gVertices     = map Down $ reverse gVertices
+    , gFromVertex   = gFromVertex . getDown
+    , gToVertex     = fmap Down . gToVertex
+    , gEdges        = gEdges'
+    , gDiff         = \(Down a) (Down b) -> gDiff b a
+    , gVerticeCount = gVerticeCount
+    , gToInt        = \(Down a) -> gVerticeCount - gToInt a - 1
+    }
+  where
+    gEdges' :: Down a -> [Down a]
+    gEdges' (Down a) = es V.! gToInt a
+
+    -- Note: in original order!
+    es :: V.Vector [Down a]
+    es = V.fromList $ map (map Down . revEdges) gVertices
+
+    revEdges :: a -> [a]
+    revEdges x = concatMap (\y -> [y | x `elem` gEdges y ]) gVertices
+
+
+-------------------------------------------------------------------------------
+-- Reduction
+-------------------------------------------------------------------------------
+
+-- | Transitive reduction.
+--
+-- Smallest graph,
+-- such that if there is a path from /u/ to /v/ in the original graph,
+-- then there is also such a path in the reduction.
+--
+-- >>> runG example $ \g -> adjacencyList $ reduction g
+-- Right [('a',"bx"),('b',"d"),('d',"e"),('e',""),('x',"d")]
+--
+-- Taking closure first doesn't matter:
+--
+-- >>> runG example $ \g -> adjacencyList $ reduction $ closure g
+-- Right [('a',"bx"),('b',"d"),('d',"e"),('e',""),('x',"d")]
+--
+reduction :: Ord a => G v a -> G v a
+reduction = transitiveImpl (== 1)
+
+-------------------------------------------------------------------------------
+-- Closure
+-------------------------------------------------------------------------------
+
+-- | Transitive closure.
+--
+-- A graph,
+-- such that if there is a path from /u/ to /v/ in the original graph,
+-- then there is an edge from /u/ to /v/ in the closure.
+--
+-- >>> runG example $ \g -> adjacencyList $ closure g
+-- Right [('a',"bdex"),('b',"de"),('d',"e"),('e',""),('x',"de")]
+--
+-- Taking reduction first, doesn't matter:
+--
+-- >>> runG example $ \g -> adjacencyList $ closure $ reduction g
+-- Right [('a',"bdex"),('b',"de"),('d',"e"),('e',""),('x',"de")]
+--
+closure :: Ord a => G v a -> G v a
+closure = transitiveImpl (/= 0)
+
+transitiveImpl :: forall v a. Ord a => (Int -> Bool) -> G v a -> G v a
+transitiveImpl pred g@G {..} = g { gEdges = gEdges' } where
+    gEdges' :: a -> [a]
+    gEdges' a = es V.! gToInt a
+
+    es :: V.Vector [a]
+    es = V.fromList $ map f gVertices where
+
+    f :: a -> [a]
+    f x = catMaybes $ zipWith edge gVertices (longestPathLengths g x)
+
+    edge y i | pred i    = Just y
+             | otherwise = Nothing
+
+-------------------------------------------------------------------------------
+-- Display
+-------------------------------------------------------------------------------
+
+-- | Recover adjacency map representation from the 'G'.
+--
+-- >>> runG example adjacencyMap
+-- Right (fromList [('a',fromList "bdex"),('b',fromList "d"),('d',fromList "e"),('e',fromList ""),('x',fromList "de")])
+adjacencyMap :: Ord v => G v a -> Map v (Set v)
+adjacencyMap G {..} = M.fromList $ map f gVertices where
+    f x = (gFromVertex x, S.fromList $ map gFromVertex $ gEdges x)
+
+-- | Adjacency list representation of 'G'.
+--
+-- >>> runG example adjacencyList
+-- Right [('a',"bdex"),('b',"d"),('d',"e"),('e',""),('x',"de")]
+adjacencyList :: Ord v => G v a -> [(v, [v])]
+adjacencyList = flattenAM . adjacencyMap
+
+flattenAM :: Map a (Set a) -> [(a, [a])]
+flattenAM = map (fmap S.toList) . M.toList
+
+-- |
+--
+-- >>> runG example $ \g@G{..} -> map (\(a,b) -> [gFromVertex a, gFromVertex b]) $  S.toList $ edgesSet g
+-- Right ["ax","ab","ad","ae","xd","xe","bd","de"]
+edgesSet :: Ord a => G v a -> Set (a, a)
+edgesSet G {..} = S.fromList
+    [ (x, y)
+    | x <- gVertices
+    , y <- gEdges x
+    ]
+
+-------------------------------------------------------------------------------
+-- Utilities
+-------------------------------------------------------------------------------
+
+-- | Like 'pairs' but for 'T.Tree'.
+treePairs :: Tree a -> [(a,a)]
+treePairs (T.Node i js) =
+    [ (i, j) | T.Node j _ <- js ] ++ concatMap treePairs js
+
+-- | Consequtive pairs.
+--
+-- >>> pairs [1..10]
+-- [(1,2),(2,3),(3,4),(4,5),(5,6),(6,7),(7,8),(8,9),(9,10)]
+--
+-- >>> pairs []
+-- []
+--
+pairs :: [a] -> [(a, a)]
+pairs [] = []
+pairs xs = zip xs (tail xs)
+
+-- | Unwrap 'Down'.
+getDown :: Down a -> a
+getDown (Down a) = a
+
+-------------------------------------------------------------------------------
+-- Setup
+-------------------------------------------------------------------------------
+
+-- $setup
+--
+-- Graph used in examples (with all arrows pointing down)
+--
+-- @
+--      a -----
+--    / | \\    \\
+--  b   |   x   \\
+--    \\ | /   \\  |
+--      d      \\ |
+--       ------- e
+-- @
+--
+-- See <https://en.wikipedia.org/wiki/Transitive_reduction> for a picture.
+--
+-- >>> let example :: Map Char (Set Char); example = M.map S.fromList $ M.fromList [('a', "bxde"), ('b', "d"), ('x', "de"), ('d', "e"), ('e', "")]
+--
+-- >>> :set -XRecordWildCards
+-- >>> import Data.Monoid (All (..))
+-- >>> import Data.Foldable (traverse_)
+--
+-- >>> let fmap2 = fmap . fmap
+-- >>> let fmap3 = fmap . fmap2
+-- >>> let traverse2_ = traverse_ . traverse_
+-- >>> let traverse3_ = traverse_ . traverse2_
+--
+-- >>> let dispTree :: Show a => Tree a -> IO (); dispTree = go 0 where go i (T.Node x xs) = putStrLn (replicate (i * 2) ' ' ++ show x) >> traverse_ (go (succ i)) xs
diff --git a/cabal-plan/src/Cabal/Plan.hs b/cabal-plan/src/Cabal/Plan.hs
new file mode 100755
index 0000000..63be81b
--- /dev/null
+++ b/cabal-plan/src/Cabal/Plan.hs
@@ -0,0 +1,576 @@
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE OverloadedStrings          #-}
+{-# LANGUAGE RecordWildCards            #-}
+
+-- | SPDX-License-Identifier: GPL-2.0-or-later
+--
+-- Utilities for reading @cabal@'s @plan.json@ file
+--
+-- @plan.json@ are generated when using @cabal@
+-- <http://cabal.readthedocs.io/en/latest/nix-local-build-overview.html Nix-style Local Builds>.
+module Cabal.Plan
+    (
+      PlanJson(..)
+    , Unit(..)
+    , CompName(..)
+    , dispCompName
+    , CompInfo(..)
+    , UnitType(..)
+
+    -- * Basic types
+    , Ver(..)
+    , dispVer
+    , PkgName(..)
+    , PkgId(..)
+    , dispPkgId
+    , UnitId(..)
+    , FlagName(..)
+
+    -- ** SHA-256
+    , Sha256
+    , dispSha256
+    , parseSha256
+    , sha256ToByteString
+    , sha256FromByteString
+
+    -- ** PkgLoc
+    , PkgLoc(..)
+    , Repo(..)
+    , SourceRepo(..)
+    , URI(..)
+    , RepoType(..)
+
+    -- * Utilities
+    , planJsonIdGraph
+    , planJsonIdRoots
+
+    -- * Convenience functions
+    , SearchPlanJson(..)
+    , findAndDecodePlanJson
+    , findProjectRoot
+    , decodePlanJson
+    ) where
+
+import           Control.Applicative          as App
+import           Control.Monad
+import           Data.Aeson
+import           Data.Aeson.Types
+import qualified Data.ByteString              as B
+import qualified Data.ByteString.Base16       as B16
+import           Data.List
+import           Data.Map                     (Map)
+import qualified Data.Map                     as M
+import           Data.Monoid
+import           Data.Set                     (Set)
+import qualified Data.Set                     as S
+import           Data.Text                    (Text)
+import qualified Data.Text                    as T
+import qualified Data.Text.Encoding           as T
+import qualified Data.Version                 as DV
+import qualified System.Directory             as Dir
+import           System.FilePath
+import           Text.ParserCombinators.ReadP
+
+----------------------------------------------------------------------------
+
+-- | Equivalent to @Cabal@'s @Distribution.Package.Version@
+newtype Ver = Ver [Int]
+            deriving (Show,Eq,Ord)
+
+-- | Equivalent to @Cabal@'s @Distribution.Package.UnitId@
+newtype UnitId = UnitId Text
+               deriving (Show,Eq,Ord,FromJSON,ToJSON,FromJSONKey,ToJSONKey)
+
+-- | Equivalent to @Cabal@'s @Distribution.Package.PackageName@
+newtype PkgName = PkgName Text
+                deriving (Show,Eq,Ord,FromJSON,ToJSON,FromJSONKey,ToJSONKey)
+
+-- | Equivalent to @Cabal@'s @Distribution.Package.PackageIdentifier@
+data PkgId = PkgId !PkgName !Ver
+           deriving (Show,Eq,Ord)
+
+-- | Equivalent to @Cabal@'s @Distribution.PackageDescription.FlagName@
+--
+-- @since 0.3.0.0
+newtype FlagName = FlagName Text
+                 deriving (Show,Eq,Ord,FromJSON,ToJSON,FromJSONKey,ToJSONKey)
+
+-- | <https://en.wikipedia.org/wiki/SHA-2 SHA-256> hash
+newtype Sha256 = Sha256 B.ByteString -- internal invariant: exactly 32 bytes long
+               deriving (Eq,Ord)
+-- | Equivalent to @Cabal@\'s @Distribution.Client.Types.PackageLocation@
+data PkgLoc
+   = LocalUnpackedPackage    !FilePath
+   | LocalTarballPackage     !FilePath
+   | RemoteTarballPackage    !URI
+   | RepoTarballPackage      !Repo
+   | RemoteSourceRepoPackage !SourceRepo
+     deriving (Show,Eq,Ord)
+
+-- | Equivalent to @Cabal@\'s @Distribution.Types.SourceRepo@
+data Repo
+   = RepoLocal  !FilePath
+   | RepoRemote !URI
+   | RepoSecure !URI
+     deriving (Show,Eq,Ord)
+
+-- | Equivalent to @Cabal@\'s @Distribution.Client.Types.Repo@
+data SourceRepo = SourceRepo
+     { srType     :: !(Maybe RepoType)
+     , srLocation :: !(Maybe Text)
+     , srModule   :: !(Maybe Text)
+     , srBranch   :: !(Maybe Text)
+     , srTag      :: !(Maybe Text)
+     , srSubdir   :: !(Maybe FilePath)
+     } deriving (Show,Eq,Ord)
+
+newtype URI = URI Text
+    deriving (Show,Eq,Ord,FromJSON,ToJSON,FromJSONKey,ToJSONKey)
+
+-- | Equivalent to @Cabal@\'s @Distribution.Client.SourceRepo.RepoType@
+data RepoType
+   = Darcs
+   | Git
+   | SVN
+   | CVS
+   | Mercurial
+   | GnuArch
+   | Bazaar
+   | Monotone
+   | OtherRepoType Text
+     deriving (Show,Eq,Ord)
+
+-- | Represents the information contained in cabal's @plan.json@ file.
+--
+-- This comprises basic information describing the environment as well
+-- as the install/build plan computed by @cabal@.
+data PlanJson = PlanJson
+     { pjCabalVersion    :: !Ver                     -- ^ Version of @cabal@ frontend
+     , pjCabalLibVersion :: !Ver                     -- ^ Version of Cabal library
+     , pjCompilerId      :: !PkgId                   -- ^ Name and version of Haskell compiler
+     , pjArch            :: !Text                    -- ^ Architecture name
+     , pjOs              :: !Text                    -- ^ Operating system name
+     , pjUnits           :: !(M.Map UnitId Unit) -- ^ install/build plan
+     } deriving Show
+
+-- | Describes kind of build unit and its provenance
+data UnitType = UnitTypeBuiltin -- ^ Lives in global (non-nix-style) package db
+              | UnitTypeGlobal  -- ^ Lives in Nix-store cache
+              | UnitTypeLocal   -- ^ Local package
+              | UnitTypeInplace -- ^ Local in-place package
+              deriving (Show,Eq)
+
+-- | Represents a build-plan unit uniquely identified by its 'UnitId'
+data Unit = Unit
+     { uId      :: !UnitId      -- ^ Unit ID uniquely identifying a 'Unit' in install plan
+     , uPId     :: !PkgId       -- ^ Package name and version (not necessarily unique within plan)
+     , uType    :: !UnitType      -- ^ Describes type of build item, see 'UnitType'
+     , uSha256  :: !(Maybe Sha256) -- ^ SHA256 source tarball checksum (as used by e.g. @hackage-security@)
+     , uComps   :: !(Map CompName CompInfo) -- ^ Components identified by 'UnitId'
+       --
+       -- When @cabal@ needs to fall back to legacy-mode (currently for
+       -- @custom@ build-types or obsolete @cabal-version@ values), 'uComps'
+       -- may contain more than one element.
+     , uFlags   :: !(Map FlagName Bool) -- ^ cabal flag settings (not available for 'UnitTypeBuiltin')
+     , uDistDir :: !(Maybe FilePath) -- ^ In-place dist-dir (if available)
+                                     --
+                                     -- @since 0.3.0.0
+     , uPkgSrc  :: !(Maybe PkgLoc)
+       -- ^ Source of the package
+       --
+       -- @since 0.5.0.0 (TODO)
+     } deriving Show
+
+-- | Component name inside a build-plan unit
+--
+-- A similiar type exists in @Cabal@ codebase, see
+-- @Distribution.Simple.LocalBuildInfo.ComponentName@
+data CompName =
+    CompNameLib
+  | CompNameSubLib !Text
+  | CompNameFLib   !Text -- ^ @since 0.3.0.0
+  | CompNameExe    !Text
+  | CompNameTest   !Text
+  | CompNameBench  !Text
+  | CompNameSetup
+  deriving (Show, Eq, Ord)
+
+-- | Describes component-specific information inside a 'Unit'
+data CompInfo = CompInfo
+    { ciLibDeps :: Set UnitId     -- ^ library dependencies
+    , ciExeDeps :: Set UnitId     -- ^ executable dependencies
+    , ciBinFile :: Maybe FilePath -- ^ path-name of artifact if available
+    } deriving Show
+
+----------------------------------------------------------------------------
+----------------------------------------------------------------------------
+----------------------------------------------------------------------------
+
+-- JSON instances
+
+instance FromJSON CompName where
+    parseJSON = withText "CompName" (maybe (fail "invalid CompName") pure . parseCompName)
+
+instance ToJSON CompName where
+    toJSON     = toJSON . dispCompName
+
+instance FromJSONKey CompName where
+    fromJSONKey = FromJSONKeyTextParser (maybe (fail "CompName") pure . parseCompName)
+
+instance ToJSONKey   CompName where
+    toJSONKey = toJSONKeyText dispCompName
+
+----
+
+instance FromJSON CompInfo where
+    parseJSON = withObject "CompInfo" $ \o ->
+        CompInfo <$> o .:?! "depends"
+                 <*> o .:?! "exe-depends"
+                 <*> o .:? "bin-file"
+
+----
+
+instance FromJSON PkgId where
+    parseJSON = withText "PkgId" (maybe (fail "invalid PkgId") pure . parsePkgId)
+
+instance ToJSON PkgId where
+    toJSON = toJSON . dispPkgId
+
+instance FromJSONKey PkgId where
+    fromJSONKey = FromJSONKeyTextParser (maybe (fail "PkgId") pure . parsePkgId)
+
+instance ToJSONKey PkgId where
+    toJSONKey = toJSONKeyText dispPkgId
+
+----
+
+instance FromJSON PkgLoc where
+    parseJSON = withObject "PkgSrc" $ \o -> do
+        ty <- o .: "type"
+        case ty :: Text of
+          "local"       -> LocalUnpackedPackage    <$> o .: "path"
+          "local-tar"   -> LocalTarballPackage     <$> o .: "path"
+          "remote-tar"  -> RemoteTarballPackage    <$> o .: "uri"
+          "repo-tar"    -> RepoTarballPackage      <$> o .: "repo"
+          "source-repo" -> RemoteSourceRepoPackage <$> o .: "source-repo"
+          _ -> fail "invalid PkgSrc \"type\""
+
+instance FromJSON Repo where
+    parseJSON = withObject "Repo" $ \o -> do
+        ty <- o .: "type"
+        case ty :: Text of
+          "local-repo"  -> RepoLocal  <$> o .: "path"
+          "remote-repo" -> RepoRemote <$> o .: "uri"
+          "secure-repo" -> RepoSecure <$> o .: "uri"
+          _ -> fail "invalid Repo \"type\""
+
+instance FromJSON SourceRepo where
+    parseJSON = withObject "SourceRepo" $ \o -> do
+        SourceRepo <$> o .:? "type"
+                   <*> o .:? "location"
+                   <*> o .:? "module"
+                   <*> o .:? "branch"
+                   <*> o .:? "tag"
+                   <*> o .:? "subdir"
+
+instance FromJSON RepoType where
+    parseJSON = withText "RepoType" $ \ty -> return $
+        case ty of
+          "darcs"     -> Darcs
+          "git"       -> Git
+          "svn"       -> SVN
+          "cvs"       -> CVS
+          "mercurial" -> Mercurial
+          "gnuarch"   -> GnuArch
+          "bazaar"    -> Bazaar
+          "monotone"  -> Monotone
+          _ -> OtherRepoType ty
+
+----------------------------------------------------------------------------
+-- parser helpers
+
+parseCompName :: Text -> Maybe CompName
+parseCompName t0 = case T.splitOn ":" t0 of
+                     ["lib"]     -> Just CompNameLib
+                     ["lib",n]   -> Just $! CompNameSubLib n
+                     ["flib",n]  -> Just $! CompNameFLib n
+                     ["exe",n]   -> Just $! CompNameExe n
+                     ["bench",n] -> Just $! CompNameBench n
+                     ["test",n]  -> Just $! CompNameTest n
+                     ["setup"]   -> Just CompNameSetup
+                     _           -> Nothing
+
+-- | Pretty print 'CompName'
+dispCompName :: CompName -> Text
+dispCompName cn = case cn of
+    CompNameLib      -> "lib"
+    CompNameSubLib n -> "lib:" <> n
+    CompNameFLib n   -> "flib:" <> n
+    CompNameExe n    -> "exe:" <> n
+    CompNameBench n  -> "bench:" <> n
+    CompNameTest n   -> "test:" <> n
+    CompNameSetup    -> "setup"
+
+instance FromJSON PlanJson where
+    parseJSON = withObject "PlanJson" $ \o -> do
+        pjCabalVersion    <- o .: "cabal-version"
+
+        unless (pjCabalVersion >= Ver [2]) $
+            fail ("plan.json version " ++ T.unpack (dispVer pjCabalVersion) ++ " not supported")
+
+        pjCabalLibVersion <- o .: "cabal-lib-version"
+        pjCompilerId      <- o .: "compiler-id"
+        pjArch            <- o .: "arch"
+        pjOs              <- o .: "os"
+        pjUnits           <- toMap =<< o .: "install-plan"
+
+        App.pure PlanJson{..}
+      where
+        toMap pil = do
+            let pim = M.fromList [ (uId pi',pi') | pi' <- pil ]
+            unless (M.size pim == length pil) $
+                fail "install-plan[] has duplicate ids"
+            pure pim
+
+(.:?!) :: (FromJSON a, Monoid a) => Object -> Text -> Parser a
+o .:?! fld = o .:? fld .!= mempty
+
+planItemAllDeps :: Unit -> Set UnitId
+planItemAllDeps Unit{..} = mconcat [ ciLibDeps <> ciExeDeps | CompInfo{..} <- M.elems uComps ]
+
+instance FromJSON Unit where
+    parseJSON = withObject "Unit" $ \o -> do
+        mcomponents    <- o .:? "components"
+        mcomponentname <- o .:? "component-name"
+        ty             <- o .:  "type"
+        mstyle         <- o .:? "style"
+
+        uId     <- o .: "id"
+        uPId    <- PkgId <$> o .: "pkg-name" <*> o .: "pkg-version"
+        uType   <- case (ty :: Text, mstyle :: Maybe Text) of
+                   ("pre-existing",Nothing)      -> pure UnitTypeBuiltin
+                   ("configured",Just "global")  -> pure UnitTypeGlobal
+                   ("configured",Just "local")   -> pure UnitTypeLocal
+                   ("configured",Just "inplace") -> pure UnitTypeInplace
+                   _                             -> fail (show (ty,mstyle))
+        uFlags  <- o .:?! "flags"
+        uSha256 <- o .:? "pkg-src-sha256"
+        uComps  <- case (mcomponents, mcomponentname) of
+          (Just comps0, Nothing) ->
+              pure comps0
+          (Nothing, Just cname) ->
+              M.singleton cname <$> parseJSON (Object o)
+          (Nothing, Nothing) | uType == UnitTypeBuiltin ->
+              M.singleton CompNameLib <$> parseJSON (Object o)
+          _ -> fail (show o)
+
+        uDistDir <- o .:? "dist-dir"
+
+        uPkgSrc <- o .:? "pkg-src"
+
+        pure Unit{..}
+
+----------------------------------------------------------------------------
+-- Convenience helper
+
+-- | Where/how to search for the plan.json file.
+data SearchPlanJson
+    = ProjectRelativeToDir FilePath -- ^ Find the project root relative to
+                                    --   specified directory and look for
+                                    --   plan.json there.
+    | InBuildDir FilePath           -- ^ Look for plan.json in specified build
+                                    --   directory.
+    deriving (Eq, Show, Read)
+
+-- | Locates the project root for cabal project relative to specified
+-- directory.
+--
+-- @plan.json@ is located from either the optional build dir argument, or in
+-- the default directory (@dist-newstyle@) relative to the project root.
+--
+-- The folder assumed to be the project-root is returned as well.
+--
+-- This function determines the project root in a slightly more liberal manner
+-- than cabal-install. If no cabal.project is found, cabal-install assumes an
+-- implicit cabal.project if the current directory contains any *.cabal files.
+--
+-- This function looks for any *.cabal files in directories above the current
+-- one and behaves as if there is an implicit cabal.project in that directory
+-- when looking for a plan.json.
+--
+-- Throws 'IO' exceptions on errors.
+--
+findAndDecodePlanJson
+    :: SearchPlanJson
+    -> IO PlanJson
+findAndDecodePlanJson searchLoc = do
+    distFolder <- case searchLoc of
+        InBuildDir builddir -> pure builddir
+        ProjectRelativeToDir fp -> do
+            mRoot <- findProjectRoot fp
+            case mRoot of
+                Nothing -> fail ("missing project root relative to: " ++ fp)
+                Just dir -> pure $ dir </> "dist-newstyle"
+
+    haveDistFolder <- Dir.doesDirectoryExist distFolder
+
+    unless haveDistFolder $
+        fail ("missing " ++ show distFolder ++ " folder; do you need to run 'cabal new-build'?")
+
+    let planJsonFn = distFolder </> "cache" </> "plan.json"
+
+    havePlanJson <- Dir.doesFileExist planJsonFn
+
+    unless havePlanJson $
+        fail "missing 'plan.json' file; do you need to run 'cabal new-build'?"
+
+    decodePlanJson planJsonFn
+
+-- | Decodes @plan.json@ file location provided as 'FilePath'
+--
+-- This is a trivial convenience function so that the caller doesn't
+-- have to depend on @aeson@ directly
+--
+-- Throws 'IO' exceptions on errors.
+--
+decodePlanJson :: FilePath -> IO PlanJson
+decodePlanJson planJsonFn = do
+    jsraw <- B.readFile planJsonFn
+    either fail pure $ eitherDecodeStrict' jsraw
+
+-- | Find project root relative to a directory, this emulates cabal's current
+-- heuristic, but is slightly more liberal. If no cabal.project is found,
+-- cabal-install looks for *.cabal files in the specified directory only. This
+-- function also considers *.cabal files in directories higher up in the
+-- hierarchy.
+findProjectRoot :: FilePath -> IO (Maybe FilePath)
+findProjectRoot dir = do
+    normalisedPath <- Dir.canonicalizePath dir
+    let checkCabalProject d = do
+            ex <- Dir.doesFileExist fn
+            return $ if ex then Just d else Nothing
+          where
+            fn = d </> "cabal.project"
+
+        checkCabal d = do
+            files <- listDirectory d
+            return $ if any (isExtensionOf ".cabal") files
+                        then Just d
+                        else Nothing
+
+    result <- walkUpFolders checkCabalProject normalisedPath
+    case result of
+        Just rootDir -> pure $ Just rootDir
+        Nothing -> walkUpFolders checkCabal normalisedPath
+  where
+    isExtensionOf :: String -> FilePath -> Bool
+    isExtensionOf ext fp = ext == takeExtension fp
+
+    listDirectory :: FilePath -> IO [FilePath]
+    listDirectory fp = filter isSpecialDir <$> Dir.getDirectoryContents fp
+      where
+        isSpecialDir f = f /= "." && f /= ".."
+
+walkUpFolders
+    :: (FilePath -> IO (Maybe a)) -> FilePath -> IO (Maybe a)
+walkUpFolders dtest d0 = do
+    home <- Dir.getHomeDirectory
+
+    let go d | d == home  = pure Nothing
+             | isDrive d  = pure Nothing
+             | otherwise  = do
+                   t <- dtest d
+                   case t of
+                     Nothing -> go $ takeDirectory d
+                     x@Just{} -> pure x
+
+    go d0
+
+parseVer :: Text -> Maybe Ver
+parseVer str = case reverse $ readP_to_S DV.parseVersion (T.unpack str) of
+  (ver, "") : _ | not (null (DV.versionBranch ver)), all (>= 0) (DV.versionBranch ver)
+      -> Just (Ver $ DV.versionBranch ver)
+  _   -> Nothing
+
+-- | Pretty print 'Ver'
+dispVer :: Ver -> Text
+dispVer (Ver ns) = T.pack $ intercalate "." (map show ns)
+
+instance FromJSON Ver where
+    parseJSON = withText "Ver" (maybe (fail "Ver") pure . parseVer)
+
+instance ToJSON Ver where
+    toJSON = toJSON . dispVer
+
+parsePkgId :: Text -> Maybe PkgId
+parsePkgId t = do
+  let (pns_, pvs) = T.breakOnEnd "-" t
+  pv <- parseVer pvs
+
+  pn <- T.stripSuffix "-" pns_
+
+  -- TODO: validate pn
+  pure (PkgId (PkgName pn) pv)
+
+-- | Pretty print 'PkgId'
+dispPkgId :: PkgId -> Text
+dispPkgId (PkgId (PkgName pn) pv) = pn <> "-" <> dispVer pv
+
+
+-- | Pretty print 'Sha256' as base-16.
+dispSha256 :: Sha256 -> Text
+dispSha256 (Sha256 s) = T.decodeLatin1 (B16.encode s)
+
+-- | Parse base-16 encoded 'Sha256'.
+--
+-- Returns 'Nothing' in case of parsing failure.
+--
+-- @since 0.3.0.0
+parseSha256 :: Text -> Maybe Sha256
+parseSha256 t
+  | B.length s == 32, B.null rest = Just (Sha256 s)
+  | otherwise                     = Nothing
+  where
+    (s, rest) = B16.decode $ T.encodeUtf8 t
+
+-- | Export the 'Sha256' digest to a 32-byte 'B.ByteString'.
+--
+-- @since 0.3.0.0
+sha256ToByteString :: Sha256 -> B.ByteString
+sha256ToByteString (Sha256 bs) = bs
+
+-- | Import the 'Sha256' digest from a 32-byte 'B.ByteString'.
+--
+-- Returns 'Nothing' if input 'B.ByteString' has incorrect length.
+--
+-- @since 0.3.0.0
+sha256FromByteString :: B.ByteString -> Maybe Sha256
+sha256FromByteString bs
+  | B.length bs == 32  = Just (Sha256 bs)
+  | otherwise          = Nothing
+
+instance FromJSON Sha256 where
+    parseJSON = withText "Sha256" (maybe (fail "Sha256") pure . parseSha256)
+
+instance ToJSON Sha256 where
+    toJSON = toJSON . dispSha256
+
+instance Show Sha256 where
+    show = show . dispSha256
+
+----------------------------------------------------------------------------
+
+-- | Extract directed 'UnitId' dependency graph edges from 'pjUnits'
+--
+-- This graph contains both, library and executable dependencies edges
+planJsonIdGraph :: PlanJson -> Map UnitId (Set UnitId)
+planJsonIdGraph PlanJson{..} = M.fromList [ (uId unit, planItemAllDeps unit)
+                                          | unit <- M.elems pjUnits
+                                          ]
+
+-- | Extract 'UnitId' root nodes from dependency graph computed by 'planJsonIdGraph'
+planJsonIdRoots :: PlanJson -> Set UnitId
+planJsonIdRoots PlanJson{..} = M.keysSet pjUnits `S.difference` nonRoots
+  where
+    nonRoots :: Set UnitId
+    nonRoots = mconcat $ M.elems $ planJsonIdGraph PlanJson{..}