fix(diff): clamp Myers edit-distance operands to clear the allocation overflow alert#3775
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…tion Follow-up to #3773: that cleared the n+m addition alert, but CodeQL still flagged the 2*maxD allocation (go/allocation-size-overflow) because it doesn't propagate maxD's bound through the guarded sum. Clamp each line count to maxDiffEdits before summing, so the sum and the 2*maxD allocation both have constant-bounded operands. maxD stays min(n+m, maxDiffEdits).
| if cm > maxDiffEdits { | ||
| cm = maxDiffEdits | ||
| } | ||
| maxD := cn + cm |
SuMuxi66
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Jun 10, 2026
…tion (esengine#3775) Follow-up to esengine#3773: that cleared the n+m addition alert, but CodeQL still flagged the 2*maxD allocation (go/allocation-size-overflow) because it doesn't propagate maxD's bound through the guarded sum. Clamp each line count to maxDiffEdits before summing, so the sum and the 2*maxD allocation both have constant-bounded operands. maxD stays min(n+m, maxDiffEdits). Co-authored-by: reasonix <reasonix@deepseek.com>
dorokuma
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Jun 10, 2026
…tion (esengine#3775) Follow-up to esengine#3773: that cleared the n+m addition alert, but CodeQL still flagged the 2*maxD allocation (go/allocation-size-overflow) because it doesn't propagate maxD's bound through the guarded sum. Clamp each line count to maxDiffEdits before summing, so the sum and the 2*maxD allocation both have constant-bounded operands. maxD stays min(n+m, maxDiffEdits). Co-authored-by: reasonix <reasonix@deepseek.com>
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Follow-up to #3773 to clear the remaining CodeQL
go/allocation-size-overflowalert.#3773 cleared the
n + maddition alert, but CodeQL kept flagging themake([]int, 2*maxD+1)allocation: it doesn't propagatemaxD's upper bound through the guarded sum, so it can't prove2*maxDwon't overflow.This clamps each line count to
maxDiffEditsbefore summing (cn,cm), so both the sum and the2*maxDallocation have operands bounded by a constant — the canonical barrier CodeQL recognizes.maxDstaysmin(n+m, maxDiffEdits), identical behavior.go build+go test ./internal/diff/pass locally.