v0.17.0 — parse Relationship from dbt manifest relationships tests

Added

• dbt manifest relationship parsing: DbtSource.get_relationships() and get_relationships_for_table() no longer return empty stubs. Each relationships schema test in the manifest (resource_type == "test", test_metadata.name == "relationships") projects into a Relationship instance. The owner model is resolved via attached_node (manifest v12+); the referenced model is taken from depends_on.nodes minus the owner (with self-FK fallback when there's only one entry). Tests that don't carry relationships semantics (not_null, unique, custom test types) are silently filtered out, as are tests whose dependencies can't be resolved to a model — manifests routinely carry tests on seeds/sources we don't track.
• meta:-block convention matches the existing _parse_metrics pattern (meta.tier, meta.domains): three optional keys on each relationships test surface end-to-end through the same code paths that already serve YamlSource-loaded relationships:
  • meta.preferred: bool — canonical-join hint, propagates to the index sort, prompt rendering, and lookup_relationships JSON.
  • meta.required_filter: str — SQL predicate enforced by RelationshipChecker.
  • meta.relationship_type: str — overrides the default many_to_one (accepts one_to_one, many_to_many).
• Index reuse: DbtSource now builds its own _rel_index via build_relationship_index, inheriting the same preferred-first stable-sort guarantee YamlSource got in v0.16.0. No new helper code; the parser is the only addition.

Documentation

• 9 new tests in tests/test_semantic/test_dbt.py (TestDbtRelationships) covering the round-trip for canonical and non-preferred edges, self-referencing FK, meta.relationship_type override, preferred-first index ordering, the referenced-side appearing in the index, self-FK appearing once not twice, non-relationships tests being filtered, and the original empty-relationships fixture continuing to return [].
• New fixture tests/fixtures/sample_dbt_manifest_with_relationships.json — a realistic manifest v12 shape with a multi-FK orders model (preferred customer_id + secondary sales_rep_id), a self-referencing employees.manager_id, and decoy not_null / unique tests to confirm filtering. Existing sample_dbt_manifest.json left untouched so it stays the empty-relationships baseline.
• README's Semantic Sources / dbt section documents the manifest convention with a schema.yml example showing all three meta: keys; architecture doc gains a paragraph describing the resolution logic and skip semantics.

Notes

• CubeSource.get_relationships() still returns [] — Cube's joins: block carries a SQL expression that needs parsing to extract column references, which is a separate piece of work. The TODO at semantic/cube.py:73 is preserved.