PR3: Schema-version observability - #88
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This was referenced Aug 26, 2026
Record the graph data-model version the server writes and report drift on
/status. Stacked on the session-node data-quality work; carries only the
schema-version subsystem (working_dir non-overwrite already shipped, blob
carrier-allowlist and cursor/queue work live in other changes).
SCHEMA_VERSION is the compiled model version, distinct from the server release
version. At startup, after the rest of the schema is established, the server
writes a single :SchemaMeta{id:'singleton'}.schema_version baseline
(create-if-absent, backed by a uniqueness constraint, kept off the per-worker
flush path so it fires once per boot rather than per worker). read path
(read_graph_schema_version) is structurally separate from the write path so no
comparison or migration logic can creep into either; it returns None on any
read failure so /status never raises.
GET /status now reports schema_version (compiled), graph_schema_version
(stored, or null when the graph is unreachable / never baselined / no driver),
and schema_version_current (true in sync, false on mismatch, null when
unknown). Advisory only: reported, never gated or migrated.
Tests: neo4j baseline idempotence + uniqueness-constraint + concurrent-writer
proofs; /status drift reporting unit tests (in-sync, drift, unknown).
Version 7.2.0.
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August 27, 2026 15:30
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Third of the progressive split of #79. Stacks on PR2 (#87, session-node data quality) → PR1 (#85) → #81 → #78.
Delivers
SCHEMA_VERSIONit wrote as a singleton baseline node (create-if-absent, no clobber, uniqueness-constrained), and/statusreports expected-vs-observed drift (schema_version/graph_schema_version/schema_version_current).Scope
Surface
schema_version_currentfield to/status→ version 7.1.0 → 7.2.0 + CHANGELOG.Verification
/version→ 7.2.0,/status→schema_version=1 graph_schema_version=1 schema_version_current=True).