stash apply: report merge conflicts

[josmith42]

Is your feature request related to a problem? Please describe.
When applying a stash that will result in conflict (e.g., the working copy has changed), gitui does not report the error message. This makes it difficult to see that a conflict occurred.

Describe the solution you'd like
A dialog box with the error message. (e.g.: "CONFLICT (content): Merge conflict in [filename]", maybe with an OK button and an Abort button.

Describe alternatives you've considered
The error message could also be in the status bar.

Additional context
If there is already error handling for stashes, maybe it could be reused.

[extrawurst]

oh I did not encounter that one yet. but does it put the conflicting files in the correct conflicted state?

[josmith42]

No, it appears to not understand the conflict state after a stash is applied:

This occurs even if the stash is applied outside of gitui.

Whereas, if you do a git status, you see the following:

On branch master
Unmerged paths:
  (use "git restore --staged <file>..." to unstage)
  (use "git add <file>..." to mark resolution)
	both modified:   conflict

no changes added to commit (use "git add" and/or "git commit -a")

[extrawurst]

which gitui version are you using?

[josmith42]

I was using 0.11.0. However, I just upgraded to 0.12.0 and it still occurs.

[extrawurst]

0.12 should tell you that the repo is in a conflicting state though 🤔

[josmith42]

It just shows M in Unstaged and Stages, the same as the above screenshot. :-(

[extrawurst]

without having reproduced this:
a) gitui currently does not support letting you resolve conflicts (#485)
b) it does not seem to work that it should show you that the repo is in a conflict resolution stage (although it should)
c) stash apply should actually refuse to do apply if this requires creating a conflict (until we support conflict resolution)

I will tackle c) in this issue

[extrawurst]

@josmith42 ok I am having trouble reproducing this. applying that results in a conflict actually is prevented

[extrawurst]

so I added unittests and it seems to me that the conflict state can only be achieved right now if applying the stash outside of gitui. I used this issue to improve on the visualisation of files in conflict state:

if you manage to achieve gitui putting files into conflicted state please provide me with a repro and feel free to reopen the issue

[josmith42]

OK, here are some steps to repro:

• Make a change to a file. Stash the change.
• Make a different change to the same file on the same line. Commit the change.
• Use gitui to apply the stash you saved in the first step.

So after #578, gitui does show the files as conflicted, but it still doesn't prevent the confilct from occurring.

To me, showing the confilct is sufficient, but if if you want gitui to prevent the conflict in the first place, it is not doing that in this case.

[josmith42]

Github won't allow me to reopen this issue, so please reopen the issue if you feel it should be based on what I reported above.

[extrawurst]

ha! committing the changes was the step I missed

[extrawurst]

comparing this again against regular git stash apply it seems to be the default behaviour to put the files into a conflicting state. meaning I will leave it like that. the only thing I am going to check now is why the diff is empty for the conflicts

[extrawurst]

superseded by #580