I tried this PR in the context of the functionality were you identified the previous fix for the interference of GIT_DIR with versioneer (context mih/datalad-mihextras#9). With this change, it leads to an unconditional fatal: KeyError('GIT_DIR') in that implementation, because it must obtain the GIT_DIR setting provided by Git to the remote helper process via this environment variable.

It seems with this PR the GIT_DIR is removed from the process environment -- and not only for versioneer, but entirely. This breaks the environment that Git remote helpers must operate in.

The relevant change seems to be this one:

-    out, rc = run_command(GITS, ["--git-dir=.git", "rev-parse", "--git-dir"], cwd=root,
-                          hide_stderr=True)
+    # GIT_DIR can interfere with correct operation of Versioneer.
+    # It may be intended to be passed to the Versioneer-versioned project,
+    # but that should not change where we get our version from.
+    os.environ.pop("GIT_DIR", None)
+
+    _, rc = runner(GITS, ["rev-parse", "--git-dir"], cwd=root,
+                   hide_stderr=True)

(from diff'ing the effective change to that DataLad extension package's code after updating versioneer in it).

It would be great if the environment modification could be constraint to versioneer itself, rather than effecting the entire process.

Thx!

Did you apply the mock as well? That is intended to protect the environment from being changed downstream.

I did not do any custom editing. I only reinstalled versioneer in the project, assuming that would be enough.

Hmm. Okay. Let me try again...

Missed @mathijsvdv's PR. Seems like a better approach.

Okay, Windows tests are passing, which was the big hold up before.

@mih Can you try again with these updates?

Hey @mih, have you had a chance to check this? If we fail again, could you share a reproduction?

Sorry for the delay. I was now able to verify that things are splendid now! Thx much for taking the time to wait for the feedback! Looking forward to the coming release.

Thanks for testing! Will plan to release today.