alexion
d03a079854
- CONVENTIONAL-COMMITS.md: vendored spec (v1.0.0); CLAUDE.md requires agent-written commits to follow it - tasks 0002-0020: remaining task breakdown of the gitea-axi spec (0019 reframed around the three-tier test taxonomy: unit, integration, end-to-end) - spec, CONTEXT.md, and ADRs 0006/0007/0011: pending design refinements from the planning sessions
31 lines
2.1 KiB
Markdown
31 lines
2.1 KiB
Markdown
# pr checkout fetches refs/pull/{index}/head, not the head branch name
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`pr checkout <n>` runs `git fetch origin pull/<n>/head:<branch>` (branch named from the PR's `head.ref`) followed by `git checkout <branch>`.
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## Considered Options
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**`git fetch origin <head-branch>`** (rejected — original spec draft) — Fails structurally for fork PRs: the head branch lives in the contributor's fork, which is not a configured remote in the operator's clone.
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This is not an edge case; fork PRs are the default contribution model.
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**Add the fork as a remote dynamically** (rejected) — Mutates the user's git configuration, requires cleanup, and needs credentials for the fork's clone URL.
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**Fetch `refs/pull/{index}/head` from the base repo** (chosen) — Gitea, like GitHub, exposes every PR's head commit on the *base* repository under `refs/pull/{index}/head`, whether the head branch lives in the same repo or a fork.
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One uniform code path, no remote mutation, no fork credentials.
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## Consequences
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- Same-repo and fork PRs check out identically.
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- Git subprocess failures (dirty worktree, network) classify as `GIT_ERROR`, carrying git's first stderr line.
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- The created local branch does not track the contributor's fork; pushing back to a fork branch is out of scope.
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## Amendment (2026-07-10): three-case handling for existing local branches
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The original two-step pipeline fails on re-checkout: git refuses to fetch into the currently checked-out branch, and a moved PR head makes the plain fetch non-fast-forward — so the second run of the same command errored, violating Principle 6.
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Amended behavior:
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1. Branch absent — original pipeline unchanged.
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2. Branch exists, not checked out — force-fetch (`+pull/<n>/head:<branch>`) then checkout; the local branch is defined as a mirror of the PR head.
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3. Branch currently checked out — fetch `pull/<n>/head` then `git merge --ff-only FETCH_HEAD`; divergence (local commits not on the PR head) surfaces as `GIT_ERROR` with explanatory help rather than being silently discarded.
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A force-reset-always variant was rejected: fully idempotent but silently destroys local commits, which is unacceptable for unattended agents.
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