A deterministic test file’s result may be reused

Re-running a test file whose content has not changed, and which is proven to give the same answer every time, spends machine time to learn nothing new. So such a file’s result may be reused, under checks that catch a reuse that should not have happened.

The user, 2026-10-15: “yes”.

• A test file’s result may be reused when the file is proven deterministic: its current content has passed repeated runs through the flake door’s runner (FLAKE-REPRO). Amended the same day by NO-LOAD-BLOCK: the proof holds under any load, judged on CPU work and events, never wall time.
• It takes one seeding pass, then re-proof of only the changed files. Flaky files are never reused.
• A random sample of reused files is re-run on every validation; a scheduled nightly cold run audits; a mismatch evicts the entry and raises an alarm.

What is missing: not built yet. Every validation runs every file.