cowork-bot: fix FK column detection in flatten mode

When flattening nested arrays, the FK column in the child table must match
the parent table's primary key column name and type. Previously the code
preferred 'name' over explicit ID fields like 'user_id' or 'users_id',
causing a type mismatch (TEXT FK vs INTEGER PK).

New priority order for parent reference key:
1. 'id' (generic primary key)
2. '{parent_table}_id' (table-specific, e.g., 'users_id')
3. Any key ending in '_id' found in parent objects (e.g., 'user_id')
4. 'name' (fallback only when no ID-like field exists)

Added 12 regression tests covering all three dialects (Postgres, MySQL, SQLite).

Author: Coding-Dev-Tools

src/json2sql.egg-info/PKG-INFO

@@ -258,9 +258,25 @@ def _flatten_nested(
         """
         child_table = f"{parent_table}_{key}"
         columns = self._infer_columns(nested_objects)
-        # Add parent reference — only if no existing column has the FK name
+        # Add parent reference — only if no existing column has the FK name.
+        # Prefer explicit ID fields over generic "name" to ensure the FK column
+        # type matches the parent table's primary key type.
         parent_ref = None
-        for pk in ("id", "name", parent_table + "_id"):
+        # Priority order for parent reference key:
+        # 1. "id" (generic primary key)
+        # 2. "{parent_table}_id" (table-specific, e.g., "users_id")
+        # 3. Any key ending in "_id" found in parent objects (e.g., "user_id")
+        # 4. "name" (fallback only when no ID-like field exists)
+        candidate_keys = ["id", f"{parent_table}_id"]
+        # Add any *_id keys found in parent objects (excluding already listed)
+        seen = set(candidate_keys)
+        for obj in parent_objs:
+            for k in obj:
+                if k.endswith("_id") and k not in seen:
+                    candidate_keys.append(k)
+                    seen.add(k)
+        candidate_keys.append("name")
+        for pk in candidate_keys:
             if any(pk in parent_obj for parent_obj in parent_objs):
                 parent_ref = pk
                 break

src/json2sql.egg-info/SOURCES.txt

@@ -131,3 +131,72 @@ def test_convert_never_emits_empty_column_list():
     )
     assert "();" not in out
     assert "INSERT INTO" in out
+
+
+class TestFlattenFKDetection:
+    """Tests for correct FK column detection in flatten mode.
+
+    The FK column in a child table must match the parent table's primary key
+    column name and type. Previously the code preferred "name" over explicit
+    ID fields like "user_id" or "users_id", causing a type mismatch.
+    """
+
+    @pytest.mark.parametrize("dialect", [Dialect.POSTGRES, Dialect.MYSQL, Dialect.SQLITE])
+    def test_flatten_prefers_id_over_name(self, dialect):
+        """When parent has both 'id' and 'name', 'id' should be used for FK."""
+        conv = JSONToSQLConverter(dialect=dialect, flatten=True)
+        data = json.dumps([
+            {"id": 1, "name": "Alice", "tags": [{"label": "x"}]},
+            {"id": 2, "name": "Bob", "tags": [{"label": "y"}]},
+        ])
+        out = conv.convert(data, table_name="users")
+        # FK column should be users_id (from parent's id), not users_name
+        assert '"users_id"' in out or '`users_id`' in out
+        assert '"users_name"' not in out and '`users_name`' not in out
+        # Parent table should have id column
+        assert '"id"' in out or '`id`' in out
+
+    @pytest.mark.parametrize("dialect", [Dialect.POSTGRES, Dialect.MYSQL, Dialect.SQLITE])
+    def test_flatten_prefers_table_specific_id(self, dialect):
+        """When parent has '{table}_id' (e.g., users_id), it should be used."""
+        conv = JSONToSQLConverter(dialect=dialect, flatten=True)
+        data = json.dumps([
+            {"users_id": 10, "name": "Alice", "tags": [{"label": "x"}]},
+            {"users_id": 20, "name": "Bob", "tags": [{"label": "y"}]},
+        ])
+        out = conv.convert(data, table_name="users")
+        # FK column should be users_users_id (from parent's users_id)
+        assert '"users_users_id"' in out or '`users_users_id`' in out
+        assert '"users_name"' not in out and '`users_name`' not in out
+
+    @pytest.mark.parametrize("dialect", [Dialect.POSTGRES, Dialect.MYSQL, Dialect.SQLITE])
+    def test_flatten_prefers_any_id_suffix(self, dialect):
+        """When parent has a singular '*_id' (e.g., user_id), it should be used over 'name'."""
+        conv = JSONToSQLConverter(dialect=dialect, flatten=True)
+        data = json.dumps([
+            {"user_id": 100, "name": "Alice", "tags": [{"label": "x"}]},
+            {"user_id": 200, "name": "Bob", "tags": [{"label": "y"}]},
+        ])
+        out = conv.convert(data, table_name="users")
+        # FK column should be users_user_id (from parent's user_id)
+        assert '"users_user_id"' in out or '`users_user_id`' in out
+        assert '"users_name"' not in out and '`users_name`' not in out
+        # FK type should be numeric (matching parent's user_id type)
+        if dialect == Dialect.MYSQL:
+            assert "INT" in out
+        else:
+            assert "INTEGER" in out
+
+    @pytest.mark.parametrize("dialect", [Dialect.POSTGRES, Dialect.MYSQL, Dialect.SQLITE])
+    def test_flatten_fallback_to_name_when_no_id(self, dialect):
+        """When parent has no ID-like field, 'name' is used as fallback."""
+        conv = JSONToSQLConverter(dialect=dialect, flatten=True)
+        data = json.dumps([
+            {"name": "Alice", "tags": [{"label": "x"}]},
+            {"name": "Bob", "tags": [{"label": "y"}]},
+        ])
+        out = conv.convert(data, table_name="users")
+        # FK column should be users_name (fallback)
+        assert '"users_name"' in out or '`users_name`' in out
+        # Parent table should have name column
+        assert '"name"' in out or '`name`' in out