stack/docs/scratchpads/t_301e4e3b-pr-merge-gitea-empty-uid.md

Scratchpad: t_301e4e3b pr-merge.sh Gitea empty-uid fallback

Task

Implement a narrow hardening in packages/mosaic/framework/tools/git/pr-merge.sh so Gitea merges recover from the known non-interactive tea pr merge identity failure: user does not exist [uid: 0, name: ].

Constraints

• Preserve Mosaic policy gates: squash-only, base branch main, queue guard unless explicitly skipped.
• Preserve the existing authenticated Gitea API fallback when no tea login exists.
• Do not fallback on arbitrary tea failures.
• Do not expose tokens or credential-bearing remotes.
• Scope is limited to the merge wrapper plus focused test/support/scratchpad files.

External issue

• Gitea issue #520: Harden pr-merge.sh Gitea empty-uid fallback

Plan

1. Add a focused shell regression harness with mocked tea and curl proving the known empty uid/name failure must fall back to Gitea API.
2. Watch the harness fail on current code.
3. Implement helper functions in pr-merge.sh for redacted command display, known failure classification, and authenticated Gitea API merge fallback.
4. Keep unknown tea failures blocking by replaying stderr and exiting non-zero.
5. Run syntax, shellcheck if available, focused regression, and repo quality gates before push/PR.

Session log

• 2026-05-22: Read Kanban context, Mosaic global/repo instructions, created isolated branch fix/t_301e4e3b-pr-merge-gitea-empty-uid, and opened Gitea issue #520 using the Mosaic issue wrapper/API fallback.
• 2026-05-22: Added regression harness and watched it fail on current behavior with user does not exist [uid: 0, name: ]; implemented narrow fallback and verified known-empty-identity fallback, arbitrary tea failure blocking, and no-tea-login API fallback paths.
• 2026-05-22: Validation passed for bash -n, shellcheck -x, focused shell harness, pnpm typecheck, pnpm lint, pnpm format:check, and pnpm --filter @mosaicstack/mosaic test. Full pnpm test exposed an out-of-scope gateway DB setup failure (relation "messages" does not exist) in apps/gateway/src/__tests__/cross-user-isolation.test.ts.