Rewrite `mastodon-auth--access-token` so it handles errors.

Currently, `mastodon-auth--access-token` unconditionally returns the
value of the `:access_token` key from the response of
`(mastodon-auth--get-token)`.  This causes problems when there was an
error getting the token, for example, if you enter the wrong
password.  If a token couldn’t be retrieved, the JSON looks like:

    (:error "invalid_grant"
     :error_description "The provided authorization grant is invalid, expired, revoked, does not match the redirection URI used in the authorization request, or was issued to another client.")

Since there is no `:access_token` key, `mastodon-auth--access-token`
returns `nil`, which results in a broken header in the next request:

    Authorization: Bearer

Which causes the whole thing to freeze Emacs until you mash `C-g`.

This commit rewrites the function to handle that case; to explicitly
signal an error for *any* response that isn’t expected; to use
`if-let`, which allows the temporary `token` variable to be
eliminated; uses `pcase` to determine what kind of response was
received; and adds ERT tests for all these cases.

0 files changed, 0 insertions, 0 deletions