debugging-and-error-recovery

Reproduce the failure reliably first, then determine whether the test or the code is wrong. Run the specific failing test in isolation to rule out test pollution, fix the root cause, and add a regression test that fails without the fix.

Run git bisect start, mark the current commit as bad and a known working commit as good, then test each midpoint checkout. You can automate it with git bisect run followed by your test command to identify the exact offending commit.

Classify whether it is timing-dependent, environment-dependent, state-dependent, or truly random. Add timestamps and logging around the suspected area, compare environments and versions, check for leaked shared state, and set up monitoring for the error signature.

Symptom fixes mask the underlying issue, which resurfaces elsewhere and compounds with later changes. Ask why the failure happens until you reach the actual cause, such as fixing a duplicate-producing query rather than deduplicating in the UI.

No. Flaky tests often mask real bugs, and skipping them lets errors compound into later work. Investigate timing issues, order dependence, or external dependencies, and fix the flakiness before resuming feature work.

Add instrumentation when you cannot localize a failure, the issue is intermittent, or multiple components interact. Remove it once the bug is fixed and guarded by tests, and always remove logs containing sensitive data.