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git.stella-ops.org/docs/features/unchecked/concelier/deterministic-semantic-merge-hash-for-advisory-deduplication.md

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Deterministic Semantic Merge Hash for Advisory Deduplication

Module

Concelier

Status

IMPLEMENTED

Description

Computes identity-based semantic hash from (CVE + PURL/CPE + version-range + CWE + patch_lineage) for cross-distro advisory deduplication. Includes normalizers (PURL, CPE, version range, CWE, patch lineage), golden corpus validation (Debian/RHEL/SUSE/Alpine), fuzzing tests (1000 random inputs), shadow-write migration mode, and backfill service. Distinct from "Advisory Ingestion with Canonical Deduplication" which is the overall dedup concept; this is the specific merge_hash identity algorithm.

Implementation Details

  • Modules: src/Concelier/__Libraries/StellaOps.Concelier.Merge/Identity/, src/Concelier/__Libraries/StellaOps.Concelier.Merge/Services/, src/Concelier/__Libraries/StellaOps.Concelier.Merge/Jobs/
  • Key Classes:
    • MergeHashCalculator (src/Concelier/__Libraries/StellaOps.Concelier.Merge/Identity/MergeHashCalculator.cs) - computes deterministic semantic hash from (CVE + PURL/CPE + version-range + CWE + patch_lineage) with input normalizers
    • MergeHashShadowWriteService (src/Concelier/__Libraries/StellaOps.Concelier.Merge/Identity/MergeHashShadowWriteService.cs) - shadow-write mode for migration validation
    • MergeHashBackfillService (src/Concelier/__Libraries/StellaOps.Concelier.Merge/Services/MergeHashBackfillService.cs) - retroactive backfill of merge hashes for existing advisories
    • MergeHashBackfillJob (src/Concelier/__Libraries/StellaOps.Concelier.Merge/Jobs/MergeHashBackfillJob.cs) - scheduled IJob for backfill execution
  • Interfaces: IMergeHashCalculator
  • Source: SPRINT_8200_0012_0001_CONCEL_merge_hash_library.md

E2E Test Plan

  • Compute merge hash for two semantically identical advisories from different sources (e.g., Debian and RHEL for same CVE) and verify identical hash output
  • Verify PURL normalization: different PURL formats for the same package produce the same merge hash
  • Verify CPE normalization: equivalent CPE strings produce identical hashes
  • Verify determinism: same input produces the same hash across 1000 repeated computations
  • Verify golden corpus: validate merge hash against the golden corpus of known Debian/RHEL/SUSE/Alpine advisories
  • Verify shadow-write mode: enable shadow writes and confirm both old and new hashes are persisted for comparison
  • Verify backfill: run MergeHashBackfillJob and confirm pre-existing advisories receive computed merge hashes