Conflict detection for PR is broken with git >= 2.32.0

[kvaster]

Gitea Version

1.16.0, 1.17.0+dev-74-g80048c091

Git Version

2.35.1, gitea demo git version

Operating System

No response

How are you running Gitea?

Built by myself and https://try.gitea.io

Database

No response

Can you reproduce the bug on the Gitea demo site?

Yes

Log Gist

No response

Description

• Create new repository
• Create commit with simple text file with simple content: 1
• Create branch feature1 with modified file content: 11
• Create PR feature1 -> master
• Create one more commit in master with modified conflicting content: 12
• Create branch feature2 with modified file content: 13
• Create PR feature2 -> master

Both feature1 and feature2 PRs will show:

• This pull request can be merged automatically.
• This branch is out-of-date with the base branch

Pressing 'Update branch by merge' or 'Update branch by rebase' will show no any visual changes (just page refresh) on demo site and will show 'Merge conflict checking is in progress. Try again in few moments' on my own install (refreshing page will show no changes).

Pressing 'Create merge commit' will show red panel reporting merge conflict with bad translation: 'editor.merge_conflict'.

Pressing 'Rebase then fast-forward' or 'Rebase then create merge commit' will show red panel reporting error message.

Pressing 'Create squash commit' will show server internal error 500.

Screenshots

[kvaster]

I found at least one problem: https://github.com/go-gitea/gitea/blame/main/services/pull/patch.go#L347

This code applies --3way additional flag for git patch apply. Here goes output of this command (git version 2.35.1, also tested with git version 2.32.0):

git apply --check --cached --3way /tmp/patch1881667419
Applied patch to 'README.md' with conflicts.

and

git apply --check --cached /tmp/patch1881667419 
error: patch failed: README.md:1
error: README.md: patch does not apply

And following code is unable to parse output with --3way argument: https://github.com/go-gitea/gitea/blame/main/services/pull/patch.go#L384