Merge pull request 'fix(precedents): נרמול case_number עמיד-להתנגשות — מדלג ומתעד, לא קורס (#145)' (#266) from worktree-backfill-citations-run into main

mcp-server/src/legal_mcp/services/db.py

@@ -4112,6 +4112,20 @@ async def get_case_law_by_citation(case_number: str) -> dict | None:
     return _row_to_case_law(row) if row else None
 
 
+async def case_number_collides(case_number: str, exclude_id: UUID) -> bool:
+    """True if assigning ``case_number`` to a NON-internal row would violate the
+    partial unique index ``uq_case_law_external_number`` (``case_number`` WHERE
+    source_kind <> 'internal_committee') — i.e. another non-internal row already owns
+    that docket. Lets a caller SKIP the identity normalization (a duplicate to dedupe
+    later) instead of crashing the whole operation on the unique violation."""
+    pool = await get_pool()
+    return bool(await pool.fetchval(
+        "SELECT 1 FROM case_law WHERE case_number = $1 AND id <> $2 "
+        "AND source_kind <> 'internal_committee' LIMIT 1",
+        case_number, exclude_id,
+    ))
+
+
 async def create_external_case_law(
     case_number: str,
     case_name: str,