fix: clearer error when a property that modifies an OpenApiDefinition is set and a DefinitionBody is defined (#3470)

Co-authored-by: GZ <[email protected]>

Author: Connor Robertson

samtranslator/swagger/swagger.py

@@ -62,7 +62,13 @@ def __init__(self, doc: Optional[Dict[str, Any]]) -> None:
         """
 
         if not doc or not SwaggerEditor.is_valid(doc):
-            raise InvalidDocumentException([InvalidTemplateException("Invalid Swagger document")])
+            raise InvalidDocumentException(
+                [
+                    InvalidTemplateException(
+                        "Invalid Swagger document or the Swagger document is not explicitly defined in 'DefinitionBody'."
+                    )
+                ]
+            )
 
         self._doc = _deepcopy(doc)
         self.paths = self._doc["paths"]

tests/translator/input/error_api_with_disable_api_endpoint_and_definition_body_with_swagger_definition_not_explicitly_in_template.yaml

@@ -0,0 +1,10 @@
+Resources:
+  LambdaApiDefinition:
+    Type: AWS::Serverless::Api
+    Properties:
+      StageName: MyStageName
+      DisableExecuteApiEndpoint: true
+      DefinitionBody:
+        Fn::If:
+        - FalseCondition
+        - swaggerdefinition.api.json

tests/translator/output/error_api_with_disable_api_endpoint_and_definition_body_with_swagger_definition_not_explicitly_in_template.json

@@ -0,0 +1,9 @@
+{
+  "_autoGeneratedBreakdownErrorMessage": [
+    "Invalid Serverless Application Specification document. ",
+    "Number of errors found: 1. ",
+    "Structure of the SAM template is invalid. ",
+    "Invalid Swagger document or the Swagger document is not explicitly defined in 'DefinitionBody'."
+  ],
+  "errorMessage": "Invalid Serverless Application Specification document. Number of errors found: 1. Structure of the SAM template is invalid. Invalid Swagger document or the Swagger document is not explicitly defined in 'DefinitionBody'."
+}