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fix(ai): agy GOCSPX scan can collect a truncated prefix at chunk boundaries — #1642's 'never truncated' guarantee fails for stable-boundary straddles #1822
Description
Finding
The chunked GOCSPX scan added by PR #1642 in packages/ai/src/providers/antigravity-auth.ts can add a truncated prefix of a secret run as a candidate, contradicting its own comment — a run that straddles the "stable region" boundary is matched truncated first, and only later matched whole. No test exercises a run straddling a chunk boundary.
Evidence
- PR: fix(ai): antigravity secret extraction tries all GOCSPX candidates (#1633) #1642 "fix(ai): antigravity secret extraction tries all GOCSPX candidates (antigravity: client-secret extraction (first GOCSPX match) stale for agy 1.4.11 — refresh fails invalid_client #1633)", merged 2026-11-04T17:33:15Z, merge commit 94c4461, head 9070d62.
- Current main 4d2d9bf, antigravity-auth.ts (blob b3145bb6f1b8, unchanged since the PR): :154 the scan reads the binary in 1 MiB chunks; :163-165
collectmatches onstable = text.slice(0, -256)for non-flush calls; :171-177 the loop setscarry = text.slice(-256)and flushes the carry at EOF. - The comment at :158-162 claims matches are collected from the stable region "so a run split across a chunk boundary is matched whole, never as a truncated prefix". That holds only for a run that starts inside the last 256 chars. A run that starts at least 17 chars before the stable boundary (7 for
GOCSPX-+ the regex's{10,}minimum) and ends after it is matched bymatchAll(/GOCSPX-[A-Za-z0-9_-]{10,}/g)in truncated form and added torunsin that form; the whole run is added only on the next chunk's pass, after the truncated one in scan order. - Candidate derivation (:~185-190) slices each run to its first 35 chars: a truncated run of 17-34 chars yields a bogus short candidate distinct from the real one, so the first refresh in a process spends an extra token-endpoint attempt on a candidate that can only be rejected
invalid_clientbefore trying the real secret (the winner cache masks this on later refreshes). - Test gap: the antigravity: client-secret extraction (first GOCSPX match) stale for agy 1.4.11 — refresh fails invalid_client #1633 tests in packages/ai/test/provider/antigravity-auth.test.ts use small single-chunk fixture binaries; no fixture places a GOCSPX run across a 1 MiB chunk boundary (or across the stable/carry boundary), so the claimed guarantee is untested.
Why it matters
The scan's correctness claim is false for exactly the boundary case it was written to handle. The practical cost today is one wasted invalid_client round-trip on a first refresh whenever a run straddles a boundary, plus a candidate list that does not match the documented invariant — and a future change that trusts the invariant (e.g. stopping at the first candidate, or capping candidate count) would turn the truncated entry into a real extraction failure.
Acceptance criteria
- A test with a fixture binary whose GOCSPX run straddles a chunk/stable boundary (at several start offsets, including 17-34 chars of the run inside the stable region) asserts the candidate set contains the whole run and no truncated prefix.
-
collectno longer emits a match that ends exactly at the stable-region boundary (or an equivalent fix), and the :158-162 comment matches the implemented guarantee. - Existing antigravity-auth candidate tests (antigravity: client-secret extraction (first GOCSPX match) stale for agy 1.4.11 — refresh fails invalid_client #1633 layouts, non-invalid_client no-cycle) keep passing.
Agent: pr-diff-review-b; state: filed; run: 2026-11-06 03:18 CST; source PR: #1642; verified against main 4d2d9bf (antigravity-auth.ts read from contents API, blob b3145bb6f1b8).
Activity
dezren39 commentedon Nov 6, 2026
🤖 Agent note · picked up
7 remaining items
dezren39 commentedon Nov 6, 2026
🤖 Agent note · triage verdict: CONFIRMED (stronger than filed)
Reproduction re-run this shift on the laptop (probes ~/git/fleet/probe-1822.ts + probe-1822b.ts against the scan logic from main; code re-verified unchanged on current main a6d8ac0 — collect at antigravity-auth.ts still matches the stable region with no end-at-boundary guard):
So #1642's 'matched whole, never as a truncated prefix' guarantee fails for stable-boundary straddles, and at offsets where the stable portion is below the regex minimum the run can be lost entirely under this chunking. Route: small_fix — collect must not emit a match ending exactly at the stable-region boundary, and the deferred run must be recovered whole later (including the lost-offset case); comment updated to the implemented guarantee; boundary tests at several offsets. Fix enqueued as a follow-up task (see next note / queue state).
dezren39 commentedon Nov 6, 2026
agent-note:v1 — follow-up fix enqueued: task 11018 (repo-health-opencode-pilot, dedupe repo-health:v1:fix:developing-today/opencode:issue:1822), packet hidden_files/10960-fix-packet-1822.json. Route per triage: suppress boundary-truncated emissions AND recover the whole run (carry back to the boundary-reaching run's start or equivalent) — dropping truncated matches alone would convert bogus-candidate cases into total loss.
dezren39 commentedon Nov 6, 2026
agent-note:v1 — state: PR #1843 open, task 11018 parked for review. Fix: collect defers any run reaching the stable-region boundary (and any sub-minimum fragment / partial GOCSPX- literal at the boundary) by carrying from the run's start, so it is matched whole on the next pass or final flush — never truncated, never lost. Tests: antigravity-auth 16 pass incl. 4 new >1MiB boundary fixtures (fail on pre-fix code); typecheck clean. Resume: disposition Codex findings on #1843, merge if sound.
Merge pull request #1843 from developing-today-forks/queue/11018-1822…