Unexpected run state encountered

When trying to backport this PR, miss-islington failed and advised running cherry_picker from the CLI. When running

cherry_picker 067597522a9002f3b8aff7f46033f10acb2381e4 3.11

It failed with this traceback:

~/projects/cpython/3.11 [3.11|✔] $ Doc/venv/bin/cherry_picker 067597522a9002f3b8aff7f46033f10acb2381e4 3.11
🐍 🍒 ⛏
Now backporting '067597522a9002f3b8aff7f46033f10acb2381e4' into '3.11'
[backport-0675975-3.11 5beb16b77f] gh-92897: Ensure `venv --copies` respects source build property of the creating interpreter (GH-92899)
 Author: Jeremy Kloth <jeremy.kloth@gmail.com>
 Date: Tue Jul 5 10:08:20 2022 -0500
 5 files changed, 76 insertions(+), 40 deletions(-)

Backport PR URL:
https://github.com/python/cpython/compare/3.11...vsajip:backport-0675975-3.11?expand=1
Traceback (most recent call last):
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/bin/cherry_picker", line 8, in <module>
    sys.exit(cherry_pick_cli())
             ^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/lib/python3.12/site-packages/click/core.py", line 1130, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/lib/python3.12/site-packages/click/core.py", line 1055, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/lib/python3.12/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/lib/python3.12/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/lib/python3.12/site-packages/click/decorators.py", line 26, in new_func
    return f(get_current_context(), *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/lib/python3.12/site-packages/cherry_picker/cherry_picker.py", line 645, in cherry_pick_cli
    cherry_picker.backport()
    ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/lib/python3.12/site-packages/cherry_picker/cherry_picker.py", line 400, in backport
    self.cleanup_branch(cherry_pick_branch)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/lib/python3.12/site-packages/cherry_picker/cherry_picker.py", line 361, in cleanup_branch
    self.checkout_default_branch()
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/lib/python3.12/site-packages/cherry_picker/cherry_picker.py", line 226, in checkout_default_branch
    self.run_cmd(cmd)
    ^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.11/Doc/venv/lib/python3.12/site-packages/cherry_picker/cherry_picker.py", line 181, in run_cmd
    output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/vinay/.local/lib/python3.12/subprocess.py", line 454, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/vinay/.local/lib/python3.12/subprocess.py", line 558, in run
    raise CalledProcessError(retcode, process.args,
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
subprocess.CalledProcessError: Command '('git', 'checkout', 'main')' returned non-zero exit status 128.

Now I was in the 3.11 branch so I'm not sure it should be doing a git checkout main. But anyway, the PR was created (in that it opened the "Create pull request" page in the browser, which I clicked to confirm - the PR is here. But if I now try to do the same thing for 3.10, I get

~/projects/cpython/3.10 [3.10|✔] $ Doc/venv/bin/cherry_picker 067597522a9002f3b8aff7f46033f10acb2381e4 3.10
🐍 🍒 ⛏
Usage: cherry_picker [OPTIONS] [COMMIT_SHA1] [BRANCHES]...
Try 'cherry_picker -h' for help.

Error: Run state cherry-picker.state=CHECKING_OUT_DEFAULT_BRANCH in Git config is not known.
Perhaps it has been set by a newer version of cherry-picker. Try upgrading.
Valid states are: BACKPORT_PAUSED, UNSET. If this looks suspicious, raise an issue at https://github.com/python/cherry-picker/issues/new.
As the last resort you can reset the runtime state stored in Git config using the following command: `git config --local --remove-section cherry-picker`

I did git config --local --remove-section cherry-picker and tried again, but now I get

~/projects/cpython/3.10 [3.10|✔] $ git config --local --remove-section cherry-picker
~/projects/cpython/3.10 [3.10|✔] $ Doc/venv/bin/cherry_picker 067597522a9002f3b8aff7f46033f10acb2381e4 3.10
🐍 🍒 ⛏
Traceback (most recent call last):
  File "/disk2/vinay/projects/cpython/3.10/Doc/venv/bin/cherry_picker", line 8, in <module>
    sys.exit(cherry_pick_cli())
             ^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.10/Doc/venv/lib/python3.12/site-packages/click/core.py", line 1130, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.10/Doc/venv/lib/python3.12/site-packages/click/core.py", line 1055, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.10/Doc/venv/lib/python3.12/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.10/Doc/venv/lib/python3.12/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.10/Doc/venv/lib/python3.12/site-packages/click/decorators.py", line 26, in new_func
    return f(get_current_context(), *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.10/Doc/venv/lib/python3.12/site-packages/cherry_picker/cherry_picker.py", line 645, in cherry_pick_cli
    cherry_picker.backport()
    ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.10/Doc/venv/lib/python3.12/site-packages/cherry_picker/cherry_picker.py", line 375, in backport
    self.fetch_upstream()
    ^^^^^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.10/Doc/venv/lib/python3.12/site-packages/cherry_picker/cherry_picker.py", line 173, in fetch_upstream
    self.run_cmd(cmd)
    ^^^^^^^^^^^^^^^^^
  File "/disk2/vinay/projects/cpython/3.10/Doc/venv/lib/python3.12/site-packages/cherry_picker/cherry_picker.py", line 181, in run_cmd
    output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/vinay/.local/lib/python3.12/subprocess.py", line 454, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/vinay/.local/lib/python3.12/subprocess.py", line 558, in run
    raise CalledProcessError(retcode, process.args,
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
subprocess.CalledProcessError: Command '['git', 'fetch', 'upstream', '--no-tags']' returned non-zero exit status 1.

traceback で示されているエントリポイント cherry_pick_cli と、backport、cleanup_branch、checkout_default_branch、fetch_upstream、run_cmd の各パスから調査を始めます。報告された 3.11 と 3.10 のコマンドを再現し、Git config の実行状態がどのように記録され、復元されるかを調べます。Done には、予期しない状態と、報告された checkout または fetch の失敗に対するカバレッジを含める必要があります。