fix array include null (#288)

datamodel_code_generator/model/pydantic/types.py

@@ -71,7 +71,7 @@
     Types.ipv6: DataType(type='IPv6Address', imports_=[IMPORT_IPV6ADDRESS]),
     Types.boolean: DataType(type='bool'),
     Types.object: DataType(type='Dict[str, Any]', imports_=[IMPORT_ANY, IMPORT_DICT,],),
-    Types.null: DataType(type='Any', imports_=[IMPORT_ANY]),
+    Types.null: DataType(type='Any', imports_=[IMPORT_ANY], is_optional=True),
     Types.array: DataType(type='List[Any]', imports_=[IMPORT_LIST, IMPORT_ANY]),
     Types.any: DataType(type='Any', imports_=[IMPORT_ANY]),
 }

datamodel_code_generator/types.py

@@ -52,6 +52,17 @@ def __init__(self, **values: Any) -> None:
         super().__init__(**values)
         if self.type and (self.reference or self.ref):
             self.unresolved_types.add(self.type)
+        for type_ in self.data_types:
+            if type_.type == 'Any' and type_.is_optional:
+                if any(t for t in self.data_types if t.type != 'Any'):
+                    self.is_optional = True
+                    self.data_types = [
+                        t
+                        for t in self.data_types
+                        if not (t.type == 'Any' and t.is_optional)
+                    ]
+                break
+
         imports: Tuple[Tuple[bool, Import], ...] = (
             (self.is_optional, IMPORT_OPTIONAL),
             (len(self.data_types) > 1, IMPORT_UNION),
@@ -100,7 +111,7 @@ def type_hint(self) -> str:
             else:
                 dict_ = 'Dict'
             type_ = f'{dict_}[str, {type_}]' if type_ else 'dict_'
-        if self.is_optional:
+        if self.is_optional and type_ != 'Any':
             type_ = f'Optional[{type_}]'
         if self.is_func:
             if self.kwargs:

tests/data/expected/main/main_json_array_include_null/output.py

@@ -0,0 +1,17 @@
+# generated by datamodel-codegen:
+#   filename:  array_include_null.json
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import List, Optional
+
+from pydantic import BaseModel
+
+
+class Item(BaseModel):
+    oofield: Optional[List[int]]
+
+
+class Model(BaseModel):
+    items: List[Item]

tests/data/json/array_include_null.json

@@ -0,0 +1,10 @@
+{
+  "items": [
+    {
+      "oofield": null
+    },
+    {
+      "oofield": [1, 2, 3]
+    }
+  ]
+}

tests/test_main.py

@@ -331,6 +331,31 @@ def test_main_json_failed():
         main()
 
 
+@freeze_time('2019-07-26')
+def test_main_json_arrary_include_null():
+    with TemporaryDirectory() as output_dir:
+        output_file: Path = Path(output_dir) / 'output.py'
+        return_code: Exit = main(
+            [
+                '--input',
+                str(JSON_DATA_PATH / 'array_include_null.json'),
+                '--output',
+                str(output_file),
+                '--input-file-type',
+                'json',
+            ]
+        )
+        assert return_code == Exit.OK
+        assert (
+            output_file.read_text()
+            == (
+                EXPECTED_MAIN_PATH / 'main_json_array_include_null' / 'output.py'
+            ).read_text()
+        )
+    with pytest.raises(SystemExit):
+        main()
+
+
 @freeze_time('2019-07-26')
 def test_main_null_and_array():
     with TemporaryDirectory() as output_dir: