Probes 7-9 (2026-05-08) all "succeeded" but with empty diffs because
AR-14a fell back to fork main: "WARNING: /workspace/reference/main/.git
not found; using fork main (may be stale)". The reference clone python
loop printed "Cloning git@..." but never "Cloned main successfully" —
no error visible either.
Most likely cause: full-history clone (post-3087ad7) is hitting some
silent failure mode (auth, fs perms, OOM, timeout). With capture_output=True
the git clone's own output was hidden.
Add explicit logging:
- python3 -u (unbuffered stdout)
- pre-loop "reference_branches loop: N entries"
- post-clone "clone returncode=N"
- always-print stdout (last 1KB) and stderr (last 1KB) from subprocess
- explicit chmod return code check
- post-clone .git existence assertion
Next probe will tell us EXACTLY what's failing.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
415118434c