Fix handling of falsy default values for enums in set-default-enum-member option (#2977)

* Fix handling of falsy default values for enums and model fields

* Add tests and JSON schema for handling falsy default enum values

* simplify handling default field values in Enum class

* rename test file name

* remove unnecessary freeze_time with statement

* test: add boolean false case to falsy default enum member fixture

---------

Co-authored-by: kkinugasa <k-kinugasa@boostry.o.jp>
Co-authored-by: Koudai Aono <koxudaxi@gmail.com>

Author: 3 people

src/datamodel_code_generator/model/enum.py

@@ -103,7 +103,7 @@ def find_member(self, value: Any) -> Member | None:
 
         for field in self.fields:
             # Remove surrounding quotes from field default value
-            field_default = str(field.default or "").strip("'\"")
+            field_default = "" if field.default is None else str(field.default).strip("'\"")
 
             # Compare values after removing quotes
             if field_default == str_value:

src/datamodel_code_generator/parser/base.py

@@ -2059,7 +2059,7 @@ def __set_default_enum_member(
         if not self.set_default_enum_member:
             return
         for _, model_field, data_type in iter_models_field_data_types(models):
-            if not model_field.default:
+            if model_field.default is None:
                 continue
             if data_type.reference and isinstance(data_type.reference.source, Enum):  # pragma: no cover
                 if isinstance(model_field.default, list):

tests/data/expected/main/jsonschema/falsy_default_enum_member.py

@@ -0,0 +1,30 @@
+# generated by datamodel-codegen:
+#   filename:  falsy_default_enum_member.json
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from enum import Enum, IntEnum
+
+from pydantic import BaseModel
+
+
+class Status(IntEnum):
+    integer_0 = 0
+    integer_1 = 1
+
+
+class Name(Enum):
+    field_ = ''
+    non_empty = 'non-empty'
+
+
+class Active(Enum):
+    boolean_True = True
+    boolean_False = False
+
+
+class Model(BaseModel):
+    status: Status | None = Status.integer_0
+    name: Name | None = Name.field_
+    active: Active | None = Active.boolean_False

tests/data/jsonschema/falsy_default_enum_member.json

@@ -0,0 +1,36 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "title": "Model",
+  "type": "object",
+  "properties": {
+    "status": {
+      "$ref": "#/$defs/Status",
+      "default": 0
+    },
+    "name": {
+      "$ref": "#/$defs/Name",
+      "default": ""
+    },
+    "active": {
+      "$ref": "#/$defs/Active",
+      "default": false
+    }
+  },
+  "$defs": {
+    "Status": {
+      "title": "Status",
+      "type": "integer",
+      "enum": [0, 1]
+    },
+    "Name": {
+      "title": "Name",
+      "type": "string",
+      "enum": ["", "non-empty"]
+    },
+    "Active": {
+      "title": "Active",
+      "type": "boolean",
+      "enum": [true, false]
+    }
+  }
+}

tests/main/jsonschema/test_main_jsonschema.py

@@ -3299,6 +3299,18 @@ def test_main_jsonschema_modular_default_enum_member(output_dir: Path) -> None:
         )
 
 
+def test_main_jsonschema_falsy_default_enum_member(output_file: Path) -> None:
+    """Test enum member mapping for falsy default values."""
+    run_main_and_assert(
+        input_path=JSON_SCHEMA_DATA_PATH / "falsy_default_enum_member.json",
+        output_path=output_file,
+        input_file_type="jsonschema",
+        assert_func=assert_file_content,
+        expected_file="falsy_default_enum_member.py",
+        extra_args=["--set-default-enum-member"],
+    )
+
+
 @pytest.mark.skipif(
     black.__version__.split(".")[0] < "22",
     reason="Installed black doesn't support Python version 3.10",