[dsyme]

Summary

Index fingerprint callbacks by source line within each file instead of invoking every result callback for every emitted line hash. Files are still hashed once and the rolling hash and fingerprint format are unchanged.

This removes the lines-times-results callback dispatch cost on files with many findings, including the repeated Object.values array creation. Multiple results on the same line still receive the same fingerprint; inconsistent existing fingerprints are preserved and still generate warnings.

Validation

• Add an upstream regression fixture covering duplicate line locations, different lines, out-of-range locations, and inconsistent existing fingerprints.
• npm run ava -- src/fingerprints.test.ts: 5 tests passed, including existing golden SARIF/hash fixtures.
• ESLint on changed TypeScript passed.
• npm run build: typecheck and bundle generation passed; regenerated lib/entry-points.js is included.
• Change-note validation passed.

Validated locally with Node 24.22.2. This PR makes no whole-analysis or fleet savings claim.

[Copilot]

🟢 Approval recommended

No active review issues block approval of the SARIF fingerprint dispatch optimization.

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What changed in this PR

Optimizes SARIF fingerprint generation by dispatching each source-line hash only to matching results, while preserving the existing hash algorithm and fingerprint behavior.

Changes:

• Indexes callbacks by line within each file, avoiding per-line iteration over every result.
• Adds regression coverage for duplicate locations, different lines, out-of-range locations, and preservation of inconsistent existing fingerprints with warnings.
• Adds a changenote describing the performance improvement.

File	Description
unreleased-change-notes/​fingerprint-callback-dispatch.md	Documents faster fingerprint generation without changing fingerprints.
src/​fingerprints.ts	Groups callbacks by source line for targeted dispatch.
src/​fingerprints.test.ts	Tests matching-line dispatch and preserved edge-case behavior.

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