1 Commits

Author	SHA1	Message	Date
Tom Boucher	953b8043ea	fix(#2456): weight test chunks by measured cost and pack with LPT (#2463) ... * fix(#2456): weight test chunks by measured cost and pack with LPT scripts/run-tests.cjs guessed each test file's cost from its filename (basename matching /^(?:install|codex-)/ scored 12, everything else 1). Measured durations show that guess is wrong in both directions: installer-migration-authoring.test.cjs scored 12 while running ~0.1s, and the two most expensive files in the suite both scored 1 — run-tests-harness.test.cjs never matched the prefix, and release-tarball-smoke.install.test.cjs was missed because the regex is anchored to the START of the basename. Chunks were therefore balanced by file COUNT, not cost. On the real shard 2/3 the two heaviest files packed into the SAME chunk, leaving the slowest chunk 2.8x the lightest and sitting near the 600s per-chunk timeout while other chunks idled. Weight each file by its measured duration from a checked-in, regenerable timings table and pack with LPT (heaviest first, into the lightest chunk). On the same shard this drops the slowest chunk from 383s to 238s and the imbalance from 2.79x to 1.00x, and separates the two heavy files. Timings are advisory, never gated: an unknown file falls back to the table's median weight, a missing or corrupt table falls back to uniform weight, and a count-based floor guarantees the packer never produces fewer chunks than plain count-based packing would. Closes #2456 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * fix(#2456): harden chunk packing against degenerate knobs and table keys Follow-up hardening found while reviewing the packer, fixed inline. The chunk knobs are read from the environment with Number(), so a typo (RUN_TESTS_MAX_FILES_PER_CHUNK=abc) yields NaN and an explicit 0 yields 0. Both flow into the new chunk-count arithmetic: NaN made Math.ceil return NaN, Array.from({length: NaN}) produce zero bins, and packChunks' retry loop spin forever — a hung CI job with no output. Zero made the count Infinity and threw RangeError: Invalid array length. The previous count-based packer degraded to a single chunk instead, so this was a regression introduced by the LPT rewrite. Normalize the knobs at the environment boundary (positiveNumberEnv: anything not a positive finite number falls back to the default) and guard packChunks itself, since it is exported and cannot assume its caller normalized. Non-finite weights from an arbitrary weightOf are clamped too. RUN_TESTS_CHUNK_TIMEOUT_MS gets the same treatment. Also resolve timing-table lookups with Object.hasOwn: the table is JSON-parsed, so a bare index would walk the prototype chain and return a function for a file named constructor.test.cjs or toString.test.cjs. The typeof guard already rejected that, but the lookup now resolves correctly rather than relying on the downstream check. Refs #2456 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * fix(#2456): correct prototype-lookup rationale and guard generator keys Two findings from independent security review, fixed inline. The makeFileWeigher comment claimed a bare table lookup "would return a FUNCTION for a file named constructor.test.cjs". That premise is false: basename('constructor.test.cjs') is 'constructor.test.cjs', which is not an Object.prototype key, and walkTestFiles only ever collects *.test.cjs. The prototype chain was never reachable from a real selection, and the existing typeof guard already rejected the function it would return, so Object.hasOwn is defense-in-depth rather than a behavior change. The comment now says that instead of asserting something untrue. The accompanying test inherited the same false premise: it fed constructor.test.cjs and asserted a median fallback that would have held with or without the guard, so it passed for a reason unrelated to what it claimed to prove. It now uses BARE keys (constructor, toString, valueOf, hasOwnProperty, __proto__) — the only inputs that actually resolve on Object.prototype — and asserts the real exported contract: any key absent from the table weighs the median, never a function. gen-test-timings.cjs built its output object by computed-key assignment from basenames taken out of a reporter stream it does not control — the js/prototype-polluting-assignment shape, and this repo has a CodeQL barrier for exactly that pattern. It was not exploitable (the value is always a rounded number, so the __proto__ setter is a silent no-op), but it silently DROPPED such an entry rather than reporting it. Validate every key against a test-basename pattern and fail loudly instead, and build the table with a null prototype. Refs #2456 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * fix(#2456): replace tautological chunking tests and clamp chunk count Six findings from independent correctness review, all reproduced and fixed inline. The two subprocess tests written to carry the #2088 guarantee forward were tautological: every seeded file weighed exactly 1, so both passed under the OLD prefix-heuristic packer and with the timings file deleted entirely. Neither could fail for the reason it existed. Both are rebuilt so the old algorithm produces a different packing and the assertion goes red: the spread test now uses three expensive files named so the old heuristic scored them 1 alongside three trivial `install-`-prefixed files it scored 12 — inverted from real cost, giving {2,2,1,1} under the old packer versus {2,2,2} under measured weights. The companion test covers the other direction: four trivial `install-` files the old heuristic split into four single-file chunks now stay in one. packChunks clamped the chunk count from below but not above, so a legitimate but tiny budget (RUN_TESTS_MAX_FILES_PER_CHUNK=1e-9, which positiveNumberEnv accepts) asked for 637,000,000,000 bins and threw RangeError. More chunks than files is never useful; the count now clamps at one file per chunk. The generator's basename-collision guard compared full dirnames, so two OS lanes reporting the same file under different container roots (/work/tests vs C:/work/tests) flagged every shared basename as a collision — on the script's own documented multi-lane usage. Detection is now scoped per stream, where the root is constant; a genuine same-lane collision is still caught. Also: the LPT tie-break compared raw paths, so a path separator (0x2F vs 0x5C) could order a subdir file differently per platform, contradicting the documented byte-identical guarantee — it now normalizes separators. loadTestTimings now honors schema_version instead of writing it and never reading it, falling back to uniform weight on an unknown version. A comment claiming an all-uniform suite "chunks exactly as it did before" was false and contradicted by this PR's own test: the chunk count is preserved, the composition is not. And the missing-table test created a temp dir it never cleaned up, for a path that only needed to not exist. Refs #2456 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>	2026-07-20 16:51:35 -04:00