We request Gitaly in a N+1 manner to build discussion diffs. Once the diffs are from different revisions, it's hard to make a single request to the service in order to build the whole response.
With this change we solve this problem and simplify a lot fetching this piece of info.
Old merge requests can have diffs without corresponding blobs. (This also may be
possible for commit diffs in corrupt repositories.)
We can't use the `&.` operator on the blobs, because the blob objects are never
nil, but `BatchLoader` instances that delegate to `Blob`. We can't use
`Object#try`, because `Blob` doesn't inherit from `Object`.
`BatchLoader` provides a `__sync` method that returns the delegated object, but
using `itself` also works because it's forwarded, and will work for
non-`BatchLoader` instances too. So the simplest solution is to just use that
with the `&.` operator.
For some old merge requests, we don't have enough information to figure out the
old blob and the new blob for the file. This means that we can't highlight the
diff correctly, but we can still display it without highlighting.
Steps to reproduce:
1. Start with a repo with an image
2. Add a commit to delete the image
3. Add another commit to replace the image with another image
In a diff comparison, we really just compare about what the image was before the diff, not
the direct parent of the last commit. This MR fixes that.
Closes#3893, gitlab-org/gitlab-ee#678
Signed-off-by: Rémy Coutable <remy@rymai.me>
Oswaldo Ferreira
Sean McGivern
Zeger-Jan van de Weg
Jacob Vosmaer
Rémy Coutable
Douwe Maan
Robert Speicher
Stan Hu
Paco Guzman
Yorick Peterse
Rubén Dávila
Douwe Maan
Jeroen van Baarsen
Dmitriy Zaporozhets