GitUp does not handle submodule conflicts

[lapfelix]

When rebasing or merging, if there's a submodule SHA1 conflict (when there's a divergence in both branches), GitUp does not handle the submodule reference conflict well at all: it displays a "Submodule not in index" alert view.

In the commit view, it seems like the submodule with a conflict is treated like a file with conflicts:

When it happens, I need to resolve the conflict with the command line or another GUI app (like SourceTree).

Sample repo

Clone this repo: https://github.com/lapfelix/test-repo-submodules
Try to merge branch1 into branch2.

[swisspol]

What happens when you click the 3 buttons?

[lapfelix]

Open with default editor:
Opens the submodule folder in Finder

Resolve In Merge Tool:

Mark as resolved:

If I try to discard the changes, the base/ item in the working directory disappears (but the 2 conflicts stay).

I can't move the submodule in the index to the working directory (or vice-versa)

If I click "Discard All..." the submodule folder gets deleted:

If I try to discard the changes to the red "base" delta cell, I get this alert view:

[lapfelix]

Looks like, in GCIndex, in - (id)initWithAncestor:(const git_index_entry*)ancestor our:(const git_index_entry*)our their:(const git_index_entry*)their;, the GCFileModeFromMode method does not support the provided git_index_entry mode, which is 57344.

[lapfelix]

I worked on a solution to this bug for myself: lapfelix/GitUp@master...lapfelix:submodule_conflict_improvements

So far it does work well, but I think it can still be improved before I open a PR.

This is what it looks like when a submodule reference conflict is encountered while performing a merge:

I still need to figure out a way to ignore the submodule addition deltas (the second table view cell in the diff contents view) when the submodule has conflicts.

If we can open the submodule in GitUp, maybe there should also be a marked as resolved button ? Though that would be the fourth button and that's a lot of buttons. Maybe there's a better way to display this ?