[Python-experimental] JSON schema 'null' type should be modeled as 'none_type'

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

@@ -2163,7 +2163,14 @@ public CodegenModel fromModel(String name, Schema schema) {
             m.xmlNamespace = schema.getXml().getNamespace();
             m.xmlName = schema.getXml().getName();
         }
-
+        if (ModelUtils.isAnyTypeSchema(schema)) {
+            // The 'null' value is allowed when the OAS schema is 'any type'.
+            // See https://github.com/OAI/OpenAPI-Specification/issues/1389
+            if (Boolean.FALSE.equals(schema.getNullable())) {
+                LOGGER.error("Schema '{}' is any type, which includes the 'null' value. 'nullable' cannot be set to 'false'", name);
+            }
+            m.isNullable = true;
+        }
         if (ModelUtils.isArraySchema(schema)) {
             m.isArrayModel = true;
             m.arrayModelType = fromProperty(name, schema).complexType;
@@ -2986,6 +2993,12 @@ public CodegenProperty fromProperty(String name, Schema p) {
         } else if (ModelUtils.isFreeFormObject(p)) {
             property.isFreeFormObject = true;
         } else if (ModelUtils.isAnyTypeSchema(p)) {
+            // The 'null' value is allowed when the OAS schema is 'any type'.
+            // See https://github.com/OAI/OpenAPI-Specification/issues/1389
+            if (Boolean.FALSE.equals(p.getNullable())) {
+                LOGGER.error("Schema '{}' is any type, which includes the 'null' value. 'nullable' cannot be set to 'false'", p.getName());
+            }
+            property.isNullable = true;
             property.isAnyType = true;
         } else if (ModelUtils.isArraySchema(p)) {
             // default to string if inner item is undefined

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

@@ -92,8 +92,8 @@ public AbstractGoCodegen() {
                         "complex128",
                         "rune",
                         "byte",
-                        "map[string]interface{}",
-                        "interface{}"
+                        "ObjectType",
+                        "AnyType"
                         )
         );
 
@@ -128,9 +128,15 @@ public AbstractGoCodegen() {
         // map[string]interface{}, whereas an arbitrary type is implemented
         // in golang as interface{}.
         // See issue #5387 for more details.
-        typeMapping.put("object", "map[string]interface{}");
-        typeMapping.put("interface{}", "interface{}");
-        typeMapping.put("AnyType", "interface{}");
+        typeMapping.put("object", "ObjectType");
+        // A schema that does not specify the 'type' attribute. The value
+        // can be anything.
+        typeMapping.put("AnyType", "AnyType");
+        // Below is the entry to map the JSON 'null' type to golang.
+        // Note there is no built-in 'null' type in golang, and it's not possible
+        // to declare a variable whose only possible value is 'nil'.
+        // For example `a := nil` is not a valid go statement.
+        typeMapping.put("null", "NullType");
 
         numberTypes = new HashSet<String>(
                 Arrays.asList(
@@ -391,7 +397,7 @@ public String getSchemaType(Schema p) {
             type = openAPIType;
         } else if ("object".equals(openAPIType) && ModelUtils.isAnyTypeSchema(p)) {
             // Arbitrary type. Note this is not the same thing as free-form object.
-            type = "interface{}";
+            type = "AnyType";
         } else if (typeMapping.containsKey(openAPIType)) {
             type = typeMapping.get(openAPIType);
             if (languageSpecificPrimitives.contains(type))
@@ -601,10 +607,10 @@ private void setExportParameterName(List<CodegenParameter> codegenParameters) {
     @Override
     public void postProcessModelProperty(CodegenModel model, CodegenProperty property) {
         // The 'go-experimental/model.mustache' template conditionally generates accessor methods.
-        // For primitive types and custom types (e.g. interface{}, map[string]interface{}...),
-        // the generated code has a wrapper type and a Get() function to access the underlying type.
-        // For containers (e.g. Array, Map), the generated code returns the type directly. 
-        if (property.isContainer || property.isFreeFormObject || property.isAnyType) {
+        // For containers (e.g. Array, Map), the generated code returns the type directly.
+        // In other cases, the generated code has a wrapper type and a Get() function to
+        // access the underlying type.
+        if (property.isContainer) {
             property.vendorExtensions.put("x-golang-is-container", true);
         }
     }

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

@@ -177,9 +177,15 @@ public Map<String, Object> postProcessModels(Map<String, Object> objs) {
                 }
 
                 for (CodegenProperty param : model.vars) {
+                    if (param.isAnyType) {
+                        param.vendorExtensions.put("x-go-base-type", "interface{}");
+                        continue;
+                    } else if (param.isFreeFormObject) {
+                        param.vendorExtensions.put("x-go-base-type", "map[string]interface{}");
+                        continue;
+                    }
                     param.vendorExtensions.put("x-go-base-type", param.dataType);
-                    if (!param.isNullable || param.isMapContainer || param.isListContainer ||
-                            param.isFreeFormObject || param.isAnyType) {
+                    if (!param.isNullable || param.isMapContainer || param.isListContainer) {
                         continue;
                     }
                     if (param.isDateTime) {

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

@@ -143,6 +143,7 @@ public PythonClientCodegen() {
         // map uuid to string for the time being
         typeMapping.put("UUID", "str");
         typeMapping.put("URI", "str");
+        typeMapping.put("null", "none_type");
 
         // from https://docs.python.org/3/reference/lexical_analysis.html#keywords
         setReservedWordsLowerCase(

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

@@ -388,7 +388,9 @@ public Map<String, Object> postProcessAllModels(Map<String, Object> objs) {
                 composedSchemaSets.add(cm.oneOf);
                 for (Set<String> importSet : composedSchemaSets) {
                     for (String otherModelName : importSet) {
-                        cm.imports.add(otherModelName);
+                        if (!languageSpecificPrimitives.contains(otherModelName)) {
+                            cm.imports.add(otherModelName);
+                        }
                     }
                 }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/OneOfImplementorAdditionalData.java

@@ -75,9 +75,11 @@ public void addFromInterfaceModel(CodegenModel cm, List<Map<String, String>> mod
         // note that we can't just toAdd.removeAll(m.vars) for every interfaceModel,
         // as they might have different value of `hasMore` and thus are not equal
         List<String> omitAdding = new ArrayList<String>();
-        for (CodegenModel m : cm.interfaceModels) {
-            for (CodegenProperty v : m.vars) {
-                omitAdding.add(v.baseName);
+        if (cm.interfaceModels != null) {
+            for (CodegenModel m : cm.interfaceModels) {
+                for (CodegenProperty v : m.vars) {
+                    omitAdding.add(v.baseName);
+                }
             }
         }
         for (CodegenProperty v : toAdd) {

modules/openapi-generator/src/main/resources/go-experimental/model.mustache

@@ -129,7 +129,12 @@ func (o *{{classname}}) Get{{name}}() {{vendorExtensions.x-go-base-type}} {
 {{/vendorExtensions.x-golang-is-container}}
 {{/isNullable}}
 {{^isNullable}}
+{{#isFreeFormObject}}
+	return o.{{name}}.Get()
+{{/isFreeFormObject}}
+{{^isFreeFormObject}}
 	return o.{{name}}
+{{/isFreeFormObject}}
 {{/isNullable}}
 }
 
@@ -151,7 +156,12 @@ func (o *{{classname}}) Get{{name}}Ok() (*{{vendorExtensions.x-go-base-type}}, b
 {{/vendorExtensions.x-golang-is-container}}
 {{/isNullable}}
 {{^isNullable}}
+{{#isFreeFormObject}}
+	return &o.{{name}}.Get(), true
+{{/isFreeFormObject}}
+{{^isFreeFormObject}}
 	return &o.{{name}}, true
+{{/isFreeFormObject}}
 {{/isNullable}}
 }
 
@@ -187,7 +197,12 @@ func (o *{{classname}}) Get{{name}}() {{vendorExtensions.x-go-base-type}} {
 {{/vendorExtensions.x-golang-is-container}}
 {{/isNullable}}
 {{^isNullable}}
+{{#isFreeFormObject}}
+	return *o.{{name}}.Get()
+{{/isFreeFormObject}}
+{{^isFreeFormObject}}
 	return *o.{{name}}
+{{/isFreeFormObject}}
 {{/isNullable}}
 }
 
@@ -209,7 +224,12 @@ func (o *{{classname}}) Get{{name}}Ok() (*{{vendorExtensions.x-go-base-type}}, b
 {{/vendorExtensions.x-golang-is-container}}
 {{/isNullable}}
 {{^isNullable}}
+{{#isFreeFormObject}}
+	return o.{{name}}.Get(), true
+{{/isFreeFormObject}}
+{{^isFreeFormObject}}
 	return o.{{name}}, true
+{{/isFreeFormObject}}
 {{/isNullable}}
 }
 
@@ -233,7 +253,12 @@ func (o *{{classname}}) Set{{name}}(v {{vendorExtensions.x-go-base-type}}) {
 {{/vendorExtensions.x-golang-is-container}}
 {{/isNullable}}
 {{^isNullable}}
+{{#isFreeFormObject}}
+	o.{{name}}.Set(&v)
+{{/isFreeFormObject}}
+{{^isFreeFormObject}}
 	o.{{name}} = &v
+{{/isFreeFormObject}}
 {{/isNullable}}
 }
 {{#isNullable}}
@@ -326,6 +351,7 @@ func (s *{{classname}}) UnmarshalJSON(src []byte) error {
 	{{/discriminator}}
 	{{^discriminator}}
 	{{#oneOf}}
+	{{! TODO: validate the payload against the JSON schema. Relying on golang JSON unmarshaling is not sufficient to determine the payload validates against the schema}}
 	var unmarshaled{{{.}}} *{{{.}}} = &{{{.}}}{}
 	err = json.Unmarshal(src, unmarshaled{{{.}}})
 	if err == nil {

modules/openapi-generator/src/main/resources/go-experimental/utils.mustache

@@ -2,7 +2,9 @@
 package {{packageName}}
 
 import (
+	"bytes"
 	"encoding/json"
+	"errors"
 	"time"
 )
 
@@ -30,6 +32,117 @@ func PtrString(v string) *string { return &v }
 // PtrTime is helper routine that returns a pointer to given Time value.
 func PtrTime(v time.Time) *time.Time { return &v }
 
+var nullLiteral []byte = []byte("null")
+
+// NullType is a type whose only value can be the JSON 'null' value.
+type NullType struct{
+	isSet bool
+}
+
+func NewNullType() *NullType {
+	return nil
+}
+
+func (v NullType) Get() interface{} {
+	return nil
+}
+
+func (v *NullType) Set() {
+	v.isSet = true
+}
+
+func (v NullType) IsSet() bool {
+	return v.isSet
+}
+
+func (v *NullType) Unset() {
+	v.isSet = false
+}
+
+func (v NullType) MarshalJSON() ([]byte, error) {
+	return nullLiteral, nil
+}
+
+func (v *NullType) UnmarshalJSON(src []byte) error {
+	if bytes.Equal(bytes.TrimSpace(nullLiteral), src) {
+		v.isSet = true
+		return nil
+	}
+	return errors.New("Cannot unmarshal value into 'null' type")
+}
+
+// AnyType is a type whose value can anything.
+type AnyType struct{
+	value *interface{}
+	isSet bool
+}
+
+func NewAnyType(val *interface{}) *AnyType {
+	return &AnyType{value: val, isSet: true}
+}
+
+func (v AnyType) Get() *interface{} {
+	return v.value
+}
+
+func (v *AnyType) Set(val *interface{}) {
+	v.value = val
+	v.isSet = true
+}
+
+func (v AnyType) IsSet() bool {
+	return v.isSet
+}
+
+func (v *AnyType) Unset() {
+	v.isSet = false
+}
+
+func (v AnyType) MarshalJSON() ([]byte, error) {
+	return json.Marshal(v.value)
+}
+
+func (v *AnyType) UnmarshalJSON(src []byte) error {
+	v.isSet = true
+	return json.Unmarshal(src, &v.value)
+}
+
+// ObjectType is a type whose value can be an object with undeclared properties.
+type ObjectType struct{
+	value *map[string]interface{}
+	isSet bool
+}
+
+func NewObjectType(val *map[string]interface{}) *ObjectType {
+	return &ObjectType{value: val, isSet: true}
+}
+
+func (v ObjectType) Get() *map[string]interface{} {
+	return v.value
+}
+
+func (v *ObjectType) Set(val *map[string]interface{}) {
+	v.value = val
+	v.isSet = true
+}
+
+func (v ObjectType) IsSet() bool {
+	return v.isSet
+}
+
+func (v *ObjectType) Unset() {
+	v.isSet = false
+}
+
+func (v ObjectType) MarshalJSON() ([]byte, error) {
+	return json.Marshal(v.value)
+}
+
+func (v *ObjectType) UnmarshalJSON(src []byte) error {
+	v.isSet = true
+	return json.Unmarshal(src, &v.value)
+}
+
 type NullableBool struct {
 	value *bool
 	isSet bool

modules/openapi-generator/src/main/resources/python/python-experimental/model_utils.mustache

@@ -1032,7 +1032,7 @@ def get_oneof_instance(self, model_args, constant_args):
             and path to item.
 
     Returns
-        oneof_instance (instance/None)
+        oneof_instance (instance)
     """
     if len(self._composed_schemas['oneOf']) == 0:
         return None
@@ -1086,9 +1086,11 @@ def get_anyof_instances(self, model_args, constant_args):
     Args:
         self: the class we are handling
         model_args (dict): var_name to var_value
-            used to make instances
+            The input data, e.g. the payload that must match at least one
+            anyOf child schema in the OpenAPI document.
         constant_args (dict): var_name to var_value
-            used to make instances
+            args that every model requires, including configuration, server
+            and path to item.
 
     Returns
         anyof_instances (list)