Git fetch fails with too long branches since 2.48.1

[JohnnyDoesStuff]

Since git 2.48.1 i got issues when fetching long branches from a repository (usecase: The repository should be fetched by Jenkins, so path lengths get past 260 characters).

Steps to reproduce:

1. Have a git repository with a branch that has a long name
2. Create a directory with a very long name
3. Open git in that directory
4. git init
5. git fetch --no-tags --force --progress --prune -- https://github.com/foo/bar.git +refs/heads/*:refs/remotes/origin/*

Expected result
Everything is fetched (When executing this with git 2.47.1 it works)

Actual Result
For the long branches i get these error messages:

error: couldn't set 'refs/remotes/origin/foo/loooooooooooooooong_branch_name'
! [new branch]          foo/loooooooooooooooong_branch_name -> origin/foo/loooooooooooooooong_branch_name  (unable to update local ref)

[jglick]

A somewhat different issue (but also apparently a recent regression) is noted in jenkins-infra/helpdesk#4574 that does not involve particularly lengthy branch names or version paths or any other detail of the repository content: that if the path to the repo root is more than about 206 characters, the fetch fails just appending the length of a SHA (jenkins-infra/helpdesk#4574 (comment)):

error: unable to write file .git/objects/88/5d62fd3383b2b55160833372cd33968adc3a97: Invalid argument

[dduportal]

The bug is still present with 2.49.0: even with the Git configuratiion core.longPaths set to true AND the Kernel setting HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem\LongPathsEnabled set to 1, the problem is still present.

For the record, it stopped working with 2.48.1, despite the settings specified in https://github.com/git-for-windows/git/blob/main/Documentation/config/core.adoc

core.longpaths

Enable long path (> 260) support for builtin commands in Git for Windows. This is disabled by default, as long paths are not supported by Windows Explorer, cmd.exe and the Git for Windows tool chain (msys, bash, tcl, perl…​). Only enable this if you know what you’re doing and are prepared to live with a few quirks.

[dscho]

/add relnote bug Git for Windows 2.48.1 introduced a regression when fetching long branches under core.longPaths = true, which was fixed.

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