3.3.0: Possible regression in cygwin DLL (Win10); fixed in snapshot

[Takashi Yano]

On Fri, 5 Nov 2021 08:42:03 -0500
Brian wrote:
> Starting  point: Cygwin 3.3.0s(0.341/5/3), Windows Version 10.0.17763 Build
> 17763, no git managers/clients initially installed.
> 
> 1.  Install git version 2.33.0 via the Cygwin installer (only the CLI).
> 2.  Download the GCM-Core 2.0.567 release zip file (
> https://github.com/microsoft/Git-Credential-Manager-Core/releases/) and
> extract somewhere.
> 3.  Copy all *.exe and *.dll files to your Cygwin /usr/libexec/git-core/
> directory.
> 4.  Set up the credential helper: 'git config --global credential.helper
> manager-core'
> 5.  Clone a repo.
> 6.  Attempt a 'git push' using the git repo's https URL.  GCM will pop up a
> browser-based UI for initial authentication.  After entering username and
> PAT credentials, and receiving the 'Everything is up-to-date' message,
> confirm that your git credentials appear in the Windows Credential Manager.
> 7.  Attempt another 'git push'.
> EXPECTED BEHAVIOR:
> 'Everything is up-to-date' (there should be no CLI or UI authentication
> prompts).
> OBSERVED BEHAVIOR:
> The user is again presented with an authentication prompts from git.
> 8.  Replace cygwin1.dll with the 0913 snapshot.
> 9.  Attempt a 'git push'.  If your credentials were cached in WCM per step
> 6, you should immediately see the 'Everything is up-to-date' reply.  If
> your credentials weren't stored for some reason, you will be prompted for
> authentication.  A subsequent 'git push' should then use your cached
> credentials.

Thanks much for the detailed steps. I could reproduce the problem.

It seems that the cause is the overhaul for the pipe implementation.
I also found the workaround for this issue. Please try:
export CYGWIN=pipe_byte

Corinna, Ken,
What about setting pipe mode to byte by default?

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>