Clean repository ROOT directory name with filepath.Clean

[MCF]

For better compatibility with Windows.

Allows UNC paths for the repository ROOT. Fixes: #2845

[codecov-io]

Codecov Report

Merging #2846 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2846   +/-   ##
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  Coverage   26.85%   26.85%           
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  Files          89       89           
  Lines       17607    17607           
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  Hits         4728     4728           
  Misses      12193    12193           
  Partials      686      686

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[MCF]

FWIW I'm already running this patch in a windows production environment. Although I applied it to the release/V1.2 branch in that case. I'm happy to provide a backport to that branch if/when this PR is accepted.

[lafriks]

Maybe change also here to filepath.Join so that behaviour is the same in both cases

[MCF]

@lafriks I've made the change you requested.

I think it is important to clarify that only filepath.Clean is really important in the context of paths based on settings that come out of app.ini. As mentioned in the related issue #2845, app.ini only allows front slashes in the repository ROOT setting. This is enforced by forcePathSeparator, which is used for a number of other settings:

$ grep forcePathSeparator modules/setting/setting.go 
func forcePathSeparator(path string) {
	forcePathSeparator(LogRootPath)
	forcePathSeparator(RepoRootPath)
	forcePathSeparator(AvatarUploadPath)

As a result the calls to path.Join vs. filepath.Join don't matter so much in this context. For example:

[repository]
ROOT = store/repos    ; front slash required.

On Windows with the a GITEA work dir of C:\gitea the resulting paths would be:

filepath.Join C:\gitea\store/repos
path.Join C:\gitea/store/repos

Fortunately either variant works with go's file and directory functions. Go seems very forgiving when it comes to this sort of problem and seems to accept either slash in path names on Windows.

TL;DR I don't think we have to worry about path.Join, only path.Clean when it comes to UNC file system paths (or any other file paths) on Windows.

[lafriks]

LGTM

[Morlinest]

LGTM