[git] merge operation without modified files cannot be completed

[federicobozzini]

Description

If a merge operation doesn't result in some file changes, it is not possible to commit. This makes impossible to complete the merge operation without using the terminal. The message shown to the user is No changes added to commit.

There is also no visual clue to the user to signal that there is an ongoing merge in this situation.

Reproduction Steps

The simplest case is the one where the user performing a merge operation sees only a conflicted file and nothing else. If none of the incoming changes is accepted, the file is not shown as modified and so it cannot be commited. But committing is necessary in this case to complete the merge operation (the git status command shows All conflicts fixed but you are still merging. (use "git commit" to conclude merge)).

If the reproduction steps are not clear I can create a repository to show the issue.

OS and Theia version:

Seen on the master version of Theia.

Diagnostics:

[westbury]

I decided to check this out using the vscode Git builtin instead of the Theia Git extension. Surprisingly it's an issue there too. See microsoft/vscode#7989. That's been open over three years.

We can fix this but only when using Theia Git extension.