[python] Fix Circular imports on inherited discriminators. (#17886)

* [python] add inheritance discriminators test #16808

* [python] update samples

* [python] fix assert in test

* [python] fix inheritance discriminators circular import

* [python] update samples

* [python] undo type changes related to discriminator

* [python] remove extraneous processing

* [python-pydantic-v1] fix inheritance discriminators circular import

* [python] remove type ignore comment

* [python] update samples

* [python] fix avoid the empty line break

* [python] update samples

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPythonCodegen.java

@@ -927,10 +927,7 @@ private ModelsMap postProcessModelsMap(ModelsMap objs) {
                 // if super class
                 if (model.getDiscriminator() != null && model.getDiscriminator().getMappedModels() != null) {
                     moduleImports.add("typing", "Union");
-                    Set<CodegenDiscriminator.MappedModel> discriminator = model.getDiscriminator().getMappedModels();
-                    for (CodegenDiscriminator.MappedModel mappedModel : discriminator) {
-                        postponedModelImports.add(mappedModel.getModelName());
-                    }
+                    moduleImports.add("importlib", "import_module");
                 }
             }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPythonPydanticV1Codegen.java

@@ -879,10 +879,6 @@ private ModelsMap postProcessModelsMap(ModelsMap objs) {
                 // if super class
                 if (model.getDiscriminator() != null && model.getDiscriminator().getMappedModels() != null) {
                     typingImports.add("Union");
-                    Set<CodegenDiscriminator.MappedModel> discriminator = model.getDiscriminator().getMappedModels();
-                    for (CodegenDiscriminator.MappedModel mappedModel : discriminator) {
-                        postponedModelImports.add(mappedModel.getModelName());
-                    }
                 }
             }
 

modules/openapi-generator/src/main/resources/python-pydantic-v1/model_generic.mustache

@@ -10,6 +10,18 @@ import json
 {{{.}}}
 {{/vendorExtensions.x-py-model-imports}}
 
+{{#hasChildren}}
+{{#discriminator}}
+{{! If this model is a super class, importlib is used. So import the necessary modules for the type here. }}
+from typing import TYPE_CHECKING
+from importlib import import_module
+if TYPE_CHECKING:
+{{#mappedModels}}
+    from {{packageName}}.models.{{model.classVarName}} import {{modelName}}
+{{/mappedModels}}
+
+{{/discriminator}}
+{{/hasChildren}}
 class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}):
     """
     {{#description}}{{{description}}}  # noqa: E501{{/description}}{{^description}}{{{classname}}}{{/description}}
@@ -222,13 +234,13 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
         {{#discriminator}}
         # look up the object type based on discriminator mapping
         object_type = cls.get_discriminator_value(obj)
-        if object_type:
-            klass = globals()[object_type]
-            return klass.from_dict(obj)
-        else:
-            raise ValueError("{{{classname}}} failed to lookup discriminator value from " +
-                             json.dumps(obj) + ". Discriminator property name: " + cls.__discriminator_property_name +
-                             ", mapping: " + json.dumps(cls.__discriminator_value_class_map))
+        {{#mappedModels}}
+        if object_type ==  '{{{mappingName}}}':
+            return import_module("{{packageName}}.models.{{model.classVarName}}").{{modelName}}.from_dict(obj)
+        {{/mappedModels}}
+        raise ValueError("{{{classname}}} failed to lookup discriminator value from " +
+                            json.dumps(obj) + ". Discriminator property name: " + cls.__discriminator_property_name +
+                            ", mapping: " + json.dumps(cls.__discriminator_value_class_map))
         {{/discriminator}}
         {{/hasChildren}}
         {{^hasChildren}}

modules/openapi-generator/src/main/resources/python/model_generic.mustache

@@ -12,6 +12,17 @@ import json
 from typing import Optional, Set
 from typing_extensions import Self
 
+{{#hasChildren}}
+{{#discriminator}}
+{{! If this model is a super class, importlib is used. So import the necessary modules for the type here. }}
+from typing import TYPE_CHECKING
+if TYPE_CHECKING:
+{{#mappedModels}}
+    from {{packageName}}.models.{{model.classVarName}} import {{modelName}}
+{{/mappedModels}}
+
+{{/discriminator}}
+{{/hasChildren}}
 class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}):
     """
     {{#description}}{{{description}}}{{/description}}{{^description}}{{{classname}}}{{/description}}
@@ -113,7 +124,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
         return json.dumps(self.to_dict())
 
     @classmethod
-    def from_json(cls, json_str: str) -> Optional[{{^hasChildren}}Self{{/hasChildren}}{{#hasChildren}}{{#discriminator}}Union[{{#children}}Self{{^-last}}, {{/-last}}{{/children}}]{{/discriminator}}{{^discriminator}}Self{{/discriminator}}{{/hasChildren}}]:
+    def from_json(cls, json_str: str) -> Optional[{{^hasChildren}}Self{{/hasChildren}}{{#hasChildren}}{{#discriminator}}Union[{{#mappedModels}}{{{modelName}}}{{^-last}}, {{/-last}}{{/mappedModels}}]{{/discriminator}}{{^discriminator}}Self{{/discriminator}}{{/hasChildren}}]:
         """Create an instance of {{{classname}}} from a JSON string"""
         return cls.from_dict(json.loads(json_str))
 
@@ -236,18 +247,19 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
 
     {{#hasChildren}}
     @classmethod
-    def from_dict(cls, obj: Dict[str, Any]) -> Optional[{{#discriminator}}Union[{{#children}}Self{{^-last}}, {{/-last}}{{/children}}]{{/discriminator}}{{^discriminator}}Self{{/discriminator}}]:
+    def from_dict(cls, obj: Dict[str, Any]) -> Optional[{{#discriminator}}Union[{{#mappedModels}}{{{modelName}}}{{^-last}}, {{/-last}}{{/mappedModels}}]{{/discriminator}}{{^discriminator}}Self{{/discriminator}}]:
         """Create an instance of {{{classname}}} from a dict"""
         {{#discriminator}}
         # look up the object type based on discriminator mapping
         object_type = cls.get_discriminator_value(obj)
-        if object_type:
-            klass = globals()[object_type]
-            return klass.from_dict(obj)
-        else:
-            raise ValueError("{{{classname}}} failed to lookup discriminator value from " +
-                             json.dumps(obj) + ". Discriminator property name: " + cls.__discriminator_property_name +
-                             ", mapping: " + json.dumps(cls.__discriminator_value_class_map))
+        {{#mappedModels}}
+        if object_type ==  '{{{mappingName}}}':
+            return import_module("{{packageName}}.models.{{model.classVarName}}").{{modelName}}.from_dict(obj)
+        {{/mappedModels}}
+
+        raise ValueError("{{{classname}}} failed to lookup discriminator value from " +
+                            json.dumps(obj) + ". Discriminator property name: " + cls.__discriminator_property_name +
+                            ", mapping: " + json.dumps(cls.__discriminator_value_class_map))
         {{/discriminator}}
     {{/hasChildren}}
     {{^hasChildren}}

modules/openapi-generator/src/test/resources/3_0/python/petstore-with-fake-endpoints-models-for-testing.yaml

@@ -1640,6 +1640,20 @@ components:
       required:
         - id
         - activity
+    DiscriminatorAllOfSuper:
+      type: object
+      required:
+        - elementType
+      discriminator:
+        propertyName: elementType
+      properties:
+        elementType:
+          type: string
+    DiscriminatorAllOfSub:
+      allOf:
+        - $ref: '#/components/schemas/DiscriminatorAllOfSuper'
+        - type: object
+          properties: {}
     Pet:
       type: object
       required:

samples/openapi3/client/petstore/python-aiohttp/.openapi-generator/FILES

@@ -30,6 +30,8 @@ docs/CreatureInfo.md
 docs/DanishPig.md
 docs/DefaultApi.md
 docs/DeprecatedObject.md
+docs/DiscriminatorAllOfSub.md
+docs/DiscriminatorAllOfSuper.md
 docs/Dog.md
 docs/DummyModel.md
 docs/EnumArrays.md
@@ -140,6 +142,8 @@ petstore_api/models/creature.py
 petstore_api/models/creature_info.py
 petstore_api/models/danish_pig.py
 petstore_api/models/deprecated_object.py
+petstore_api/models/discriminator_all_of_sub.py
+petstore_api/models/discriminator_all_of_super.py
 petstore_api/models/dog.py
 petstore_api/models/dummy_model.py
 petstore_api/models/enum_arrays.py

samples/openapi3/client/petstore/python-aiohttp/README.md

@@ -164,6 +164,8 @@ Class | Method | HTTP request | Description
  - [CreatureInfo](docs/CreatureInfo.md)
  - [DanishPig](docs/DanishPig.md)
  - [DeprecatedObject](docs/DeprecatedObject.md)
+ - [DiscriminatorAllOfSub](docs/DiscriminatorAllOfSub.md)
+ - [DiscriminatorAllOfSuper](docs/DiscriminatorAllOfSuper.md)
  - [Dog](docs/Dog.md)
  - [DummyModel](docs/DummyModel.md)
  - [EnumArrays](docs/EnumArrays.md)

samples/openapi3/client/petstore/python-aiohttp/docs/DiscriminatorAllOfSub.md

@@ -0,0 +1,28 @@
+# DiscriminatorAllOfSub
+
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+
+## Example
+
+```python
+from petstore_api.models.discriminator_all_of_sub import DiscriminatorAllOfSub
+
+# TODO update the JSON string below
+json = "{}"
+# create an instance of DiscriminatorAllOfSub from a JSON string
+discriminator_all_of_sub_instance = DiscriminatorAllOfSub.from_json(json)
+# print the JSON string representation of the object
+print DiscriminatorAllOfSub.to_json()
+
+# convert the object into a dict
+discriminator_all_of_sub_dict = discriminator_all_of_sub_instance.to_dict()
+# create an instance of DiscriminatorAllOfSub from a dict
+discriminator_all_of_sub_form_dict = discriminator_all_of_sub.from_dict(discriminator_all_of_sub_dict)
+```
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/python-aiohttp/docs/DiscriminatorAllOfSuper.md

@@ -0,0 +1,29 @@
+# DiscriminatorAllOfSuper
+
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**element_type** | **str** |  | 
+
+## Example
+
+```python
+from petstore_api.models.discriminator_all_of_super import DiscriminatorAllOfSuper
+
+# TODO update the JSON string below
+json = "{}"
+# create an instance of DiscriminatorAllOfSuper from a JSON string
+discriminator_all_of_super_instance = DiscriminatorAllOfSuper.from_json(json)
+# print the JSON string representation of the object
+print DiscriminatorAllOfSuper.to_json()
+
+# convert the object into a dict
+discriminator_all_of_super_dict = discriminator_all_of_super_instance.to_dict()
+# create an instance of DiscriminatorAllOfSuper from a dict
+discriminator_all_of_super_form_dict = discriminator_all_of_super.from_dict(discriminator_all_of_super_dict)
+```
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/python-aiohttp/petstore_api/__init__.py

@@ -63,6 +63,8 @@
 from petstore_api.models.creature_info import CreatureInfo
 from petstore_api.models.danish_pig import DanishPig
 from petstore_api.models.deprecated_object import DeprecatedObject
+from petstore_api.models.discriminator_all_of_sub import DiscriminatorAllOfSub
+from petstore_api.models.discriminator_all_of_super import DiscriminatorAllOfSuper
 from petstore_api.models.dog import Dog
 from petstore_api.models.dummy_model import DummyModel
 from petstore_api.models.enum_arrays import EnumArrays

samples/openapi3/client/petstore/python-aiohttp/petstore_api/models/__init__.py

@@ -39,6 +39,8 @@
 from petstore_api.models.creature_info import CreatureInfo
 from petstore_api.models.danish_pig import DanishPig
 from petstore_api.models.deprecated_object import DeprecatedObject
+from petstore_api.models.discriminator_all_of_sub import DiscriminatorAllOfSub
+from petstore_api.models.discriminator_all_of_super import DiscriminatorAllOfSuper
 from petstore_api.models.dog import Dog
 from petstore_api.models.dummy_model import DummyModel
 from petstore_api.models.enum_arrays import EnumArrays

samples/openapi3/client/petstore/python-aiohttp/petstore_api/models/animal.py

@@ -17,11 +17,17 @@
 import re  # noqa: F401
 import json
 
+from importlib import import_module
 from pydantic import BaseModel, Field, StrictStr
 from typing import Any, ClassVar, Dict, List, Optional, Union
 from typing import Optional, Set
 from typing_extensions import Self
 
+from typing import TYPE_CHECKING
+if TYPE_CHECKING:
+    from petstore_api.models.cat import Cat
+    from petstore_api.models.dog import Dog
+
 class Animal(BaseModel):
     """
     Animal
@@ -64,7 +70,7 @@ def to_json(self) -> str:
         return json.dumps(self.to_dict())
 
     @classmethod
-    def from_json(cls, json_str: str) -> Optional[Union[Self, Self]]:
+    def from_json(cls, json_str: str) -> Optional[Union[Cat, Dog]]:
         """Create an instance of Animal from a JSON string"""
         return cls.from_dict(json.loads(json_str))
 
@@ -89,20 +95,17 @@ def to_dict(self) -> Dict[str, Any]:
         return _dict
 
     @classmethod
-    def from_dict(cls, obj: Dict[str, Any]) -> Optional[Union[Self, Self]]:
+    def from_dict(cls, obj: Dict[str, Any]) -> Optional[Union[Cat, Dog]]:
         """Create an instance of Animal from a dict"""
         # look up the object type based on discriminator mapping
         object_type = cls.get_discriminator_value(obj)
-        if object_type:
-            klass = globals()[object_type]
-            return klass.from_dict(obj)
-        else:
-            raise ValueError("Animal failed to lookup discriminator value from " +
-                             json.dumps(obj) + ". Discriminator property name: " + cls.__discriminator_property_name +
-                             ", mapping: " + json.dumps(cls.__discriminator_value_class_map))
-
-from petstore_api.models.cat import Cat
-from petstore_api.models.dog import Dog
-# TODO: Rewrite to not use raise_errors
-Animal.model_rebuild(raise_errors=False)
+        if object_type ==  'Cat':
+            return import_module("petstore_api.models.cat").Cat.from_dict(obj)
+        if object_type ==  'Dog':
+            return import_module("petstore_api.models.dog").Dog.from_dict(obj)
+
+        raise ValueError("Animal failed to lookup discriminator value from " +
+                            json.dumps(obj) + ". Discriminator property name: " + cls.__discriminator_property_name +
+                            ", mapping: " + json.dumps(cls.__discriminator_value_class_map))
+
 

samples/openapi3/client/petstore/python-aiohttp/petstore_api/models/discriminator_all_of_sub.py

@@ -0,0 +1,86 @@
+# coding: utf-8
+
+"""
+    OpenAPI Petstore
+
+    This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+
+    The version of the OpenAPI document: 1.0.0
+    Generated by OpenAPI Generator (https://openapi-generator.tech)
+
+    Do not edit the class manually.
+"""  # noqa: E501
+
+
+from __future__ import annotations
+import pprint
+import re  # noqa: F401
+import json
+
+from typing import Any, ClassVar, Dict, List
+from petstore_api.models.discriminator_all_of_super import DiscriminatorAllOfSuper
+from typing import Optional, Set
+from typing_extensions import Self
+
+class DiscriminatorAllOfSub(DiscriminatorAllOfSuper):
+    """
+    DiscriminatorAllOfSub
+    """ # noqa: E501
+    __properties: ClassVar[List[str]] = ["elementType"]
+
+    model_config = {
+        "populate_by_name": True,
+        "validate_assignment": True,
+        "protected_namespaces": (),
+    }
+
+
+    def to_str(self) -> str:
+        """Returns the string representation of the model using alias"""
+        return pprint.pformat(self.model_dump(by_alias=True))
+
+    def to_json(self) -> str:
+        """Returns the JSON representation of the model using alias"""
+        # TODO: pydantic v2: use .model_dump_json(by_alias=True, exclude_unset=True) instead
+        return json.dumps(self.to_dict())
+
+    @classmethod
+    def from_json(cls, json_str: str) -> Optional[Self]:
+        """Create an instance of DiscriminatorAllOfSub from a JSON string"""
+        return cls.from_dict(json.loads(json_str))
+
+    def to_dict(self) -> Dict[str, Any]:
+        """Return the dictionary representation of the model using alias.
+
+        This has the following differences from calling pydantic's
+        `self.model_dump(by_alias=True)`:
+
+        * `None` is only added to the output dict for nullable fields that
+          were set at model initialization. Other fields with value `None`
+          are ignored.
+        """
+        excluded_fields: Set[str] = set([
+        ])
+
+        _dict = self.model_dump(
+            by_alias=True,
+            exclude=excluded_fields,
+            exclude_none=True,
+        )
+        return _dict
+
+    @classmethod
+    def from_dict(cls, obj: Optional[Dict[str, Any]]) -> Optional[Self]:
+        """Create an instance of DiscriminatorAllOfSub from a dict"""
+        if obj is None:
+            return None
+
+        if not isinstance(obj, dict):
+            return cls.model_validate(obj)
+
+        _obj = cls.model_validate({
+            "elementType": obj.get("elementType")
+        })
+        return _obj
+
+