fix(compact): preserve base-tier adjacency when source node is dirty

[temporaryfix]

Fixes #345.

Summary

LayeredStore::edges_from and neighbors short-circuited the base layer whenever the source node was marked dirty. ensure_in_overlay (the only path that flags a node dirty in this context) copies labels and properties into the overlay but never copies adjacency, so a snapshot-tier edge whose endpoint was later touched by any overlay write — a property update, or merely being the endpoint of an unrelated new edge — silently vanished from reads.

In GQL this surfaces as property-anchored edge patterns such as MATCH (a {id: $x})-[:T]->(b {id: $y}) returning zero rows once any overlay write has occurred, because the planner may walk from either anchor and one of them is now dirty.

See #345 for the full root-cause analysis, minimal reproduction, and observed impact.

Fix

Drop the is_node_dirty guard in both methods. Safety of the change:

• Per-edge deletions are still authoritative via deleted_from_base_edges.
• Promoted edges (whose properties were modified, so they live at the same EdgeId in base and overlay) are collapsed by the existing dedup_by_key(eid) pass at the end of edges_from.
• delete_node_edges walks base.load().edges_from(...) directly and was never affected by the guard.
• As a side benefit, sum_of(edges_from(n).len()) is now consistent with edge_count() for dirty source nodes (it wasn't before).

The minor cost: traversals from a dirty source node now read both base and overlay adjacency rather than just overlay. That's the necessary cost of returning the correct answer.

Regression coverage

• New test_base_edge_visible_from_promoted_endpoint — promotes both endpoints via unrelated overlay writes and asserts the original base edge remains reachable from both directions, via both edges_from and neighbors.
• New post_compact_property_anchored_edge_survives_unrelated_overlay_write — GQL integration test that mirrors the production repro for both promotion directions.
• Strengthened test_edges_from_dirty_source_merges_layers and test_neighbors_from_promoted_node_with_new_overlay_edges — the existing tests asserted only the new overlay edge and explicitly documented the bug in their comments. They now assert the merge behavior their names promise.

All four new/strengthened tests fail on the pre-fix code (confirmed by running them against main before applying the fix).

Test plan

• cargo test -p grafeo-core --features "compact-store lpg" — 2017 + 27 + 5 + 61 tests pass.
• cargo test -p grafeo-engine --features "compact-store lpg gql" --test post_compact_overlay_visibility — 6/6 pass (5 existing + 1 new).
• cargo test -p grafeo-engine --features "compact-store lpg gql" across post_compact_index, post_compact_numeric_content, compact_store_integration, compact_roundtrip_proptest, compact_store_tiered_spill, snapshot, database_api, backward_compatibility, mvcc_integration, versioning_coverage, temporal_properties, savepoint_undo, label_rollback, set_property_rollback, grafeo_file, golden_format, schema_wal_replay, wal_recovery — all pass.
• Pre-existing compile errors in query_correctness.rs and merge_rollback.rs (both call removed/renamed methods execute_sql/execute_cypher) are reproducible on clean main and are unrelated to this change.

🤖 Generated with Claude Code

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Summary by cubic

Preserves base-tier adjacency when a node becomes dirty so existing snapshot edges remain visible. Restores correct results for property-anchored edge queries in GQL after overlay writes to either endpoint.

• Bug Fixes
  • Always read base adjacency in neighbors and edges_from, even when the source node is dirty; merge with overlay, respect per-edge deletions, and dedup by EdgeId.
  • Fixes double-anchored patterns like MATCH (a {id: ...})-[:T]->(b {id: ...}) returning zero rows after unrelated overlay writes.
  • Adds regression coverage (unit + GQL tests) for promoted endpoints in both directions.
  • Minor trade-off: traversals from dirty nodes now read both base and overlay.

^{Written for commit 70c9b92. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 2 files

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[temporaryfix]

Would you like me to target the release branch once you have triaged this?

[codspeed-hq]

Merging this PR will not alter performance

✅ 70 untouched benchmarks

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_{Comparing temporaryfix:fix/overlay-edge-property-lookup (70c9b92) with main (4ebae02)}