fix(stack): derive repository from git remote when --repository is not provided

[JulianMaurin]

The stack checkout command crashed with AttributeError: 'NoneType' object has no attribute 'split'
when --repository was omitted, because the option had no default. Now falls back to resolving
the user/repo from the git remote URL, consistent with stack list and stack push.

Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com

[JulianMaurin]

This pull request is part of a stack:

1. fix(stack): derive repository from git remote when --repository is not provided (#1123) 👈
2. fix(stack): normalize --branch by stripping prefix and change ID suffix (#1124)

[mergify]

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[Copilot]

Pull request overview

Fixes mergify stack checkout crashing when --repository is omitted by deriving owner/repo from the configured git remote URL (aligned with how stack list / stack push resolve the repository).

Changes:

• Make --repository optional in stack checkout and fall back to parsing remote.<trunk-remote>.url.
• Add tests covering: no stacked PRs, deriving repository from remote, and honoring an explicit --repository.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
mergify_cli/stack/cli.py	Updates checkout CLI handler to derive user/repo from git remote when --repository is not provided.
mergify_cli/tests/stack/test_checkout.py	Adds new async tests for checkout behavior and repository resolution paths.

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Pull request has been modified.

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-04-10 13:38 UTC · Rule: default
• ✅ Checks passed · on draft merge queue: embarking main (9c2de62), #1115 and #1123 together #1130
• ✅ Merged — 2026-04-10 13:41 UTC · at fe99c6c3a1182113c01df54ec2b3b741bc242bb6

This pull request spent 2 minutes 28 seconds in the queue, including 1 minute 55 seconds running CI.

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• all of [🛡 Merge Protections rule Enforce conventional commit]:
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    • fix(stack): derive repository from git remote when --repository is not provided #1123
• all of [🛡 Merge Protections rule 👀 Review Requirements]:
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      • fix(stack): derive repository from git remote when --repository is not provided #1123
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      • fix(stack): derive repository from git remote when --repository is not provided #1123
    • author = mergify-ci-bot
      • fix(stack): derive repository from git remote when --repository is not provided #1123
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      • fix(stack): derive repository from git remote when --repository is not provided #1123
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    • fix(stack): derive repository from git remote when --repository is not provided #1123
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    • fix(stack): derive repository from git remote when --repository is not provided #1123
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