From 2105887042e5bca3b364a04ed74aecc13d70ce7f Mon Sep 17 00:00:00 2001
From: Holger Dürer <me@hdurer.net>
Date: Wed, 7 Jun 2017 18:29:10 +0100
Subject: Catch any errors thrown during url-retrieve.

On Emacs24 I've been able to reliably fail url fetching which exposed issues in loading a timeline (it aborts the loading).
This catches any errors, marking the image load as failed so that we won't retry (retries are a TODO item I guess) and then succeeds the function so the rest of the timeline loading can proceed.
---
 lisp/mastodon-media.el       | 15 ++++++++++++---
 test/mastodon-media-tests.el | 18 ++++++++++++++++++
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/lisp/mastodon-media.el b/lisp/mastodon-media.el
index 0a4c3de..50f79dd 100644
--- a/lisp/mastodon-media.el
+++ b/lisp/mastodon-media.el
@@ -170,9 +170,18 @@ MEDIA-TYPE is a symbol and either 'avatar or 'media-link."
                            `(:height ,mastodon-media--avatar-height))
                           ((eq media-type 'media-link)
                            `(:max-height ,mastodon-media--preview-max-height))))))
-    (url-retrieve url
-                  #'mastodon-media--process-image-response
-                  (list (copy-marker start) image-options region-length))))
+    (let ((buffer (current-buffer))
+          (marker (copy-marker start)))
+      (condition-case nil
+          ;; catch any errors in url-retrieve so as to not abort
+          ;; whatever called us
+          (url-retrieve url
+                        #'mastodon-media--process-image-response
+                        (list marker image-options region-length))
+        (error (with-current-buffer buffer
+                 ;; TODO: Consider adding retries
+                 (put-text-property marker (+ marker region-length) 'media-state 'loading-failed)
+                 :loading-failed))))))
 
 (defun mastodon-media--select-next-media-line ()
   "Find coordinates of the next media to load.
diff --git a/test/mastodon-media-tests.el b/test/mastodon-media-tests.el
index 4bb89c7..7031e90 100644
--- a/test/mastodon-media-tests.el
+++ b/test/mastodon-media-tests.el
@@ -111,6 +111,24 @@
         (let ((mastodon-media--preview-max-height 321))
           (should (eq :called-as-expected (mastodon-media--load-image-from-url url 'media-link 7 5))))))))
 
+(ert-deftest mastodon-media:load-image-from-url:url-fetching-fails ()
+  "Should cope with failures in url-retrieve."
+  (let ((url "http://example.org/image.png")
+        (mastodon-media--avatar-height 123))
+    (with-mock
+      (mock (image-type-available-p 'imagemagick) => t)
+      (mock (create-image * 'imagemagick t :height 123) => '(image foo))
+      (stub url-retrieve => (error "url-retrieve failed"))
+
+      (with-temp-buffer
+        (insert (concat "Start:"
+                        (mastodon-media--get-avatar-rendering "http://example.org/img.png")
+                        ":rest"))
+
+        (should (eq :loading-failed (mastodon-media--load-image-from-url url 'avatar 7 1)))
+        ;; the media state was updated so we won't load this again: 
+        (should (eq 'loading-failed (get-text-property 7 'media-state)))))))
+
 (ert-deftest mastodon-media:process-image-response ()
   "Should process the HTTP response and adjust the source buffer."
   (with-temp-buffer
-- 
cgit v1.2.3