ci: retry smoke tests to absorb Cloudflare edge propagation flakes

[alukach]

What I'm changing

The smoke-test job fails intermittently on PR previews (e.g. run 30306016560 attempt 1, which passed unchanged on attempt 2). The failures are not ours: the 404 bodies are Cloudflare's <title>Page not found</title> workers.dev placeholder, and they interleave with passing requests to the same host in the same second.

A freshly deployed Worker propagates per edge machine, not per hostname. For a few seconds after wrangler deploy, some requests to multistore-proxy-pr-N.<subdomain>.workers.dev land on a machine that does not have the script yet and get the placeholder 404; neighbouring requests succeed. In that run test_assume_role_returns_credentials passed at 21:16:13.3 while the fixture behind test_assume_no_access_role_returns_credentials 404'd at 21:16:13.4.

The existing Wait for deployment to be live gate (3 consecutive successful probes) cannot close this: it probes one URL and its probes may all be answered by machines that are already warm, so it reports live while others still 404.

How I did it

• .github/workflows/deploy.yml — Run smoke tests now installs pytest-rerunfailures and runs with --reruns 4 --reruns-delay 5, giving ~20s of retry coverage for the propagation window. Comment above the step records why the deploy-side probe loop cannot solve this instead.

Retries are scoped to the smoke job only; tests/integration/ in ci.yml is unchanged. A genuine regression fails all five attempts, so this hides nothing — it costs ~20s on a real failure.

Test plan

• deploy.yml parses (yaml.safe_load)
• Confirmed pytest-rerunfailures retries fixture setup errors, not just test-body failures — the smoke suite's 404s surface as setup errors on the assume_no_access fixture, so this was the load-bearing assumption. Verified with a throwaway suite whose fixture raises on its first two invocations: 1 passed, 2 rerun.

🤖 Generated with Claude Code

[github-actions]

🚀 Latest commit deployed to https://multistore-proxy-pr-132.development-seed.workers.dev

• Date: 2026-07-27T21:47:16Z
• Commit: 0627727