Enforce single-PR-per-program invariant: preserve-branch-name, existing_pr/head_branch, no-suffix prose

[Copilot]

gh-aw silently appends a hex salt to safe-output branches on collision, so every program's second iteration spawned a fresh draft PR instead of pushing to the existing one — a long-running program ended up with a stack of 10+ orphan PRs. Fixing this requires three coordinated pieces (config + scheduler + prose); any one alone is bypassable.

A. Config — workflows/autoloop.md safe-outputs

• create-pull-request.preserve-branch-name: true so gh-aw stops auto-suffixing the canonical autoloop/{program} branch.
• max: 1 on both create-pull-request and push-to-pull-request-branch (one safe-output of either kind per iteration, never both).

B. Scheduler — new existing_pr / head_branch outputs

New helper find_existing_pr_for_branch(repo, program_name, github_token) in workflows/scripts/autoloop_scheduler.py (mirrored to .github/workflows/scripts/) queries the open draft PR for autoloop/{program-name} and writes both fields into /tmp/gh-aw/autoloop.json:

• Strategy 1: exact head=owner:autoloop/{name} query.
• Strategy 2 fallback: paginate open PRs and match either a legacy framework-suffixed branch (autoloop/{name}-[0-9a-f]{6,40}) or a [Autoloop: {name}] title prefix — so installations upgrading from before preserve-branch-name: true find their in-flight PR instead of opening a duplicate.

The HTTP layer is broken out into a module-level _http_get_json helper so tests can inject a stub via the http_get_json parameter without touching urllib.

head_branch is always exactly autoloop/{program-name} (never null when a program is selected); existing_pr is the PR number or null.

C. Prose

• "⚠️ CRITICAL — Branch Name Must Be Exact" callout under Branch Naming Convention with the three forbidden suffix patterns.
• Step 5a (Push and wait for CI) item 3 rewritten into ordered sub-steps: (a) check existing_pr, (b) state-file PR field as fallback (closed/merged → treat as null), (c) only then create-pull-request with explicit branch: from head_branch. Step 5c (Accept) instructs the agent to use push-to-pull-request-branch rather than create-pull-request whenever a PR already exists.
• New "Common Mistakes to Avoid" section restating the no-suffix and no-duplicate-PR rules.

Tests

8 new tests across tests/test_scheduling.py and tests/test_scheduler_e2e.py:

• TestSafeOutputsConfig / TestProseGuidance — assert the config flags and prose anchors are present (regression guards against silent removal).
• TestFindExistingPRForBranch — drives the new Python helper with a stubbed http_get_json covering no-PR, canonical hit, hex-suffix fallback, title-prefix fallback, and two negative cases (autoloop/coverage-extras and autoloop/signal must not match coverage / signal_processing).
• Two new e2e tests run the scheduler end-to-end and assert head_branch == "autoloop/{name}" when a program is selected and head_branch is None when nothing is selected.

Out of scope

• Regenerating .github/workflows/autoloop.lock.yml (deployment-time gh aw compile).
• Upstream gh-aw bug create-pull-request: preserve-branch-name silently bypassed when remote branch already exists github/gh-aw#27454 where preserve-branch-name: true is bypassed on remote-branch collision; pieces B and C hold the invariant even before that lands.

[mrjf]

@copilot resolve merge conflicts, and fix failing tests

[Copilot]

@copilot resolve merge conflicts, and fix failing tests

Done in 1dfeaa6. Merged origin/main, ported findExistingPRForBranch from the removed JS heredoc to Python (find_existing_pr_for_branch in workflows/scripts/autoloop_scheduler.py, mirrored to .github/workflows/scripts/), re-applied the prose changes on top of main's new Step 5a/5b/5c CI-gated accept flow, and rewrote the tests to call the Python helper directly with a stubbed http_get_json (no more Node subprocess). All 123 tests pass.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• https://api.github.com/repos/bogus.invalid/bogus/issues
  • Triggering command: /usr/bin/python /usr/bin/python /home/REDACTED/work/autoloop/autoloop/workflows/scripts/autoloop_scheduler.py (http block)
• https://api.github.com/repos/bogus.invalid/bogus/pulls
  • Triggering command: /usr/bin/python /usr/bin/python /home/REDACTED/work/autoloop/autoloop/workflows/scripts/autoloop_scheduler.py (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)