relative submodule PR diff links not working

[AdamMajer]

Description

This is a followup for #35033 and related to the FIXME in sources:

gitea/modules/git/commit_submodule_file.go

Lines 40 to 43 in 56eccb4

	// FIXME: when handling relative path, this logic is not right. It needs to:
	// 1. Remember the submodule's full path and its commit's repo home link
	// 2. Resolve the relative path: targetRepoLink = path.Join(repoHomeLink, path.Dir(submoduleFullPath), refURL)
	// Not an easy task and need to refactor related code a lot.

When submodule uses relative repository paths, the submodule diff link in a PR is invalid, for example,

https://demo.gitea.com/gnuman/rel_submodule_test/pulls/1/files

lists the diff as:
https://demo.gitea.com/gnuman/rel_submodule_test/gnuman/foo.git/compare/1890948776e76bdb05f4b55acc6c035143d3fbce...e16d0fe2f699d9855e381a792e83ed3e7e134e52

instead of
https://demo.gitea.com/gnuman/foo.git/compare/1890948776e76bdb05f4b55acc6c035143d3fbce...e16d0fe2f699d9855e381a792e83ed3e7e134e52

and the submodule link is also invalid in the PR as:
https://demo.gitea.com/gnuman/rel_submodule_test/gnuman/foo.git

Gitea Version

main

Can you reproduce the bug on the Gitea demo site?

Yes

Log Gist

No response

Screenshots

No response

Git Version

No response

Operating System

No response

How are you running Gitea?

demo.gitea.com

Database

None

[wxiaoguang]

-> Fix submodule relative path handling #35056

[AdamMajer]

This still seems to be an issue with relative submodules in subdirectories. Maybe the unit tests are not so correct. For example,

[submodule "rel1"]
	path = foo/bar/rel1
	url = ../test

If the repository is

gitea.demo.com/org/repo

The above submodule is then mounted on path,

gitea.demo.com/org/repo/foo/bar/rel1 -> gitea.demo.com/org/test

but Gitea resolution seems to apply the relative url to the path, and not just the repository location. No matter where the submodule is moved to, the path changes, but the relative url remains as-is. The above example would then be resolved in Gitea as,

gitea.demo.com/org/repo/foo/bar/rel1 -> gitea.demo.com/org/repo/foo/test

Screenshot from my example running again main branch,

[AdamMajer]

So, just to spell it out, by default, the name of the submodule is equal to its path when it's initially created. So,

Submodule created as ok/here/too

[submodule "ok/here/too"]
	path = ok/here/too
	url = ../test

Then I move it to ok as ok/too

[submodule "ok/here/too"]
	path = ok/too
	url = ../test

So,

[submodule "name"]
    path=mount_point
    url=repo_location

The name is arbitrary. It just has to be unique. The path is what's important locally and the url is relative to local repository and has nothing to do with submodule name or mount_point.

[wxiaoguang]

What do you think about this fix? Fix various bugs #35177

[AdamMajer]

Testing now and I see that it does fix the URL in the file listing. Thanks! The left-side directory listing is broken still, and the link leads to a crash

results in,

[wxiaoguang]

Testing now and I see that it does fix the URL in the file listing. Thanks! The left-side directory listing is broken still, and the link leads to a crash

It needs another fix to fix the "TODO" in legacy code. I have to admit there are too many legacy problems ........

-> Fix repo file list partial reloading for submodules #35183