[python-fastapi] dont inherit additionalProperties

Don't let models inherit the value type of additionalProperties and arrays.

This is to fix a bug where the `python-fastapi` server generator generated invalid models that inherited the value type specified within additionalProperties.

Author: mgoltzsche

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

@@ -140,6 +140,11 @@ public PythonFastAPIServerCodegen() {
                 .defaultValue(implPackage));
     }
 
+    @Override
+    protected void addParentFromContainer(CodegenModel model, Schema schema) {
+        // we do not want to inherit simply because additionalProperties is set
+    }
+
     @Override
     public void processOpts() {
         super.processOpts();

modules/openapi-generator/src/test/java/org/openapitools/codegen/python/PythonFastapiCodegenTest.java

@@ -1,9 +1,17 @@
 package org.openapitools.codegen.python;
 
+import com.google.common.collect.Sets;
+import io.swagger.v3.oas.models.OpenAPI;
+import io.swagger.v3.oas.models.media.ArraySchema;
+import io.swagger.v3.oas.models.media.Schema;
 import org.openapitools.codegen.CodegenConstants;
+import org.openapitools.codegen.CodegenModel;
+import org.openapitools.codegen.DefaultCodegen;
 import org.openapitools.codegen.DefaultGenerator;
 import org.openapitools.codegen.TestUtils;
 import org.openapitools.codegen.config.CodegenConfigurator;
+import org.openapitools.codegen.languages.PythonClientCodegen;
+import org.testng.Assert;
 import org.testng.annotations.Test;
 
 import java.io.File;
@@ -53,4 +61,24 @@ public void testEndpointSpecsWithoutDescription() throws IOException {
         TestUtils.assertFileContains(Paths.get(output + "/src/nodesc/apis/desc_api.py"),
                 "return await BaseDescApi.subclasses[0]().desc()\n");
     }
+
+    @Test(description = "additionalProperties should not let container type inherit their type")
+    public void additionalPropertiesModelTest() {
+        final Schema model = new ArraySchema()
+                //.description()
+                .items(new Schema().type("object").additionalProperties(new Schema().type("string")))
+                .description("model with additionalProperties");
+        final DefaultCodegen codegen = new PythonClientCodegen();
+        OpenAPI openAPI = TestUtils.createOpenAPIWithOneSchema("sample", model);
+        codegen.setOpenAPI(openAPI);
+        final CodegenModel cm = codegen.fromModel("sample", model);
+
+        Assert.assertEquals(cm.name, "sample");
+        Assert.assertEquals(cm.classname, "Sample");
+        Assert.assertEquals(cm.description, "model with additionalProperties");
+        Assert.assertEquals(cm.vars.size(), 0);
+        Assert.assertEquals(cm.parent, "null<Dict>");
+        Assert.assertEquals(cm.imports.size(), 0);
+        Assert.assertEquals(Sets.intersection(cm.imports, Sets.newHashSet()).size(), 0);
+    }
 }