fix: add validation for API property Model (#2340)

samtranslator/model/eventsources/push.py

@@ -5,7 +5,7 @@
 from samtranslator.model import ResourceMacro, PropertyType
 from samtranslator.model.eventsources import FUNCTION_EVETSOURCE_METRIC_PREFIX
 from samtranslator.model.types import is_type, list_of, dict_of, one_of, is_str
-from samtranslator.model.intrinsics import ref, fnGetAtt, fnSub, make_shorthand, make_conditional
+from samtranslator.model.intrinsics import is_intrinsic, ref, fnGetAtt, fnSub, make_shorthand, make_conditional
 from samtranslator.model.tags.resource_tagging import get_tag_list
 
 from samtranslator.model.s3 import S3Bucket
@@ -767,6 +767,14 @@ def _add_swagger_integration(self, api, function, intrinsics_resolver):
                             model=method_model, method=self.Method, path=self.Path
                         ),
                     )
+                if not is_intrinsic(api_models) and not isinstance(api_models, dict):
+                    raise InvalidEventException(
+                        self.relative_id,
+                        "Unable to set RequestModel [{model}] on API method [{method}] for path [{path}] "
+                        "because the related API Models defined is of invalid type.".format(
+                            model=method_model, method=self.Method, path=self.Path
+                        ),
+                    )
                 if not isinstance(method_model, str):
                     raise InvalidEventException(
                         self.relative_id,

tests/translator/input/error_api_with_models_of_invalid_type.yaml

@@ -0,0 +1,37 @@
+Resources:
+  MyApi:
+    Type: AWS::Serverless::Api
+    Properties:
+      StageName: Prod
+      Models:
+        - Invalid_value
+
+  MyFunction:
+    Type: AWS::Serverless::Function
+    Properties:
+      Handler: index.handler
+      Runtime: nodejs12.x
+      InlineCode: |
+        exports.handler = async (event, context, callback) => {
+          return {
+            statusCode: 200,
+            body: 'Success'
+          }
+        }
+      Events:
+        None:
+          Type: Api
+          Properties:
+            RequestModel:
+              Model: User
+              Required: true
+            RestApiId:
+              Ref: MyApi
+            Method: get
+            Path: /none
+
+Outputs:
+  ApiUrl:
+    Description: "API endpoint URL for Prod environment"
+    Value:
+      Fn::Sub: 'https://${MyApi}.execute-api.${AWS::Region}.${AWS::URLSuffix}/Prod/'

tests/translator/output/error_api_with_models_of_invalid_type.json

@@ -0,0 +1,3 @@
+{
+  "errorMessage": "Invalid Serverless Application Specification document. Number of errors found: 2. Resource with id [MyApi] is invalid. Type of property 'Models' is invalid. Resource with id [MyFunction] is invalid. Event with id [None] is invalid. Unable to set RequestModel [User] on API method [get] for path [/none] because the related API Models defined is of invalid type."
+}