perf: Avoid copy.deepcopy calls in some cases

src/schemathesis/specs/openapi/converter.py

@@ -4,13 +4,14 @@
 from ...utils import traverse_schema
 
 
-def to_json_schema(schema: Dict[str, Any], nullable_name: str) -> Dict[str, Any]:
+def to_json_schema(schema: Dict[str, Any], *, nullable_name: str, copy: bool = True) -> Dict[str, Any]:
     """Convert Open API parameters to JSON Schema.
 
     NOTE. This function is applied to all keywords (including nested) during a schema resolving, thus it is not recursive.
     See a recursive version below.
     """
-    schema = deepcopy(schema)
+    if copy:
+        schema = deepcopy(schema)
     if schema.get(nullable_name) is True:
         del schema[nullable_name]
         schema = {"anyOf": [schema, {"type": "null"}]}
@@ -21,4 +22,4 @@ def to_json_schema(schema: Dict[str, Any], nullable_name: str) -> Dict[str, Any]
 
 
 def to_json_schema_recursive(schema: Dict[str, Any], nullable_name: str) -> Dict[str, Any]:
-    return traverse_schema(schema, to_json_schema, nullable_name)
+    return traverse_schema(schema, to_json_schema, nullable_name=nullable_name)

src/schemathesis/specs/openapi/schemas.py

@@ -492,7 +492,7 @@ def _rewritten_components(self) -> Dict[str, Any]:
         if not hasattr(self, "__rewritten_components"):
 
             def callback(_schema: Dict[str, Any], nullable_name: str) -> Dict[str, Any]:
-                _schema = to_json_schema(_schema, nullable_name)
+                _schema = to_json_schema(_schema, nullable_name=nullable_name, copy=False)
                 return self._rewrite_references(_schema, self.resolver)
 
             # pylint: disable=attribute-defined-outside-init

test/test_converter.py

@@ -36,4 +36,4 @@
     ),
 )
 def test_to_jsonschema_recursive(schema, expected):
-    assert traverse_schema(schema, converter.to_json_schema, "x-nullable") == expected
+    assert traverse_schema(schema, converter.to_json_schema, nullable_name="x-nullable") == expected