fix: enforcing unique function names

azure/functions/decorators/function_app.py

@@ -204,6 +204,8 @@ def __str__(self):
 
 
 class FunctionBuilder(object):
+    function_bindings: dict = {}
+
     def __init__(self, func, function_script_file):
         self._function = Function(func, function_script_file)
 
@@ -232,6 +234,12 @@ def _validate_function(self,
         """
         Validates the function information before building the function.
 
+        Functions with the same function name are not supported and should
+        fail indexing. If a function name is not defined, the default is the
+        method name. This also means that two functions with the same
+        method name will also fail indexing.
+        https://github.com/Azure/azure-functions-python-worker/issues/1489
+
         :param auth_level: Http auth level that will be set if http
         trigger function auth level is None.
         """
@@ -262,6 +270,16 @@ def _validate_function(self,
                         parse_singular_param_to_enum(auth_level, AuthLevel))
             self._function._is_http_function = True
 
+        # This dict contains the function name and its bindings for all
+        # functions in an app. If a previous function has the same name,
+        # indexing will fail here.
+        if self.function_bindings.get(function_name, None):
+            raise ValueError(
+                f"Function {function_name} does not have a unique"
+                f" function name. Please change @app.function_name() or"
+                f" the function method name to be unique.")
+        self.function_bindings[function_name] = bindings
+
     def build(self, auth_level: Optional[AuthLevel] = None) -> Function:
         """
         Validates and builds the function object.
@@ -3333,11 +3351,13 @@ class ExternalHttpFunctionApp(
     @abc.abstractmethod
     def _add_http_app(self,
                       http_middleware: Union[
-                          AsgiMiddleware, WsgiMiddleware]) -> None:
+                          AsgiMiddleware, WsgiMiddleware],
+                      function_name: str = 'http_app_func') -> None:
         """Add a Wsgi or Asgi app integrated http function.
 
         :param http_middleware: :class:`WsgiMiddleware`
                                 or class:`AsgiMiddleware` instance.
+        :param function_name: name for the function
 
         :return: None
         """
@@ -3346,17 +3366,18 @@ def _add_http_app(self,
 
 class AsgiFunctionApp(ExternalHttpFunctionApp):
     def __init__(self, app,
-                 http_auth_level: Union[AuthLevel, str] = AuthLevel.FUNCTION):
+                 http_auth_level: Union[AuthLevel, str] = AuthLevel.FUNCTION,
+                 function_name: str = 'http_app_func'):
         """Constructor of :class:`AsgiFunctionApp` object.
 
         :param app: asgi app object.
         :param http_auth_level: Determines what keys, if any, need to be
-        present
-        on the request in order to invoke the function.
+        present on the request in order to invoke the function.
+        :param function_name: function name
         """
         super().__init__(auth_level=http_auth_level)
         self.middleware = AsgiMiddleware(app)
-        self._add_http_app(self.middleware)
+        self._add_http_app(self.middleware, function_name)
         self.startup_task_done = False
 
     def __del__(self):
@@ -3365,7 +3386,8 @@ def __del__(self):
 
     def _add_http_app(self,
                       http_middleware: Union[
-                          AsgiMiddleware, WsgiMiddleware]) -> None:
+                          AsgiMiddleware, WsgiMiddleware],
+                      function_name: str = 'http_app_func') -> None:
         """Add an Asgi app integrated http function.
 
         :param http_middleware: :class:`WsgiMiddleware`
@@ -3379,6 +3401,7 @@ def _add_http_app(self,
 
         asgi_middleware: AsgiMiddleware = http_middleware
 
+        @self.function_name(name=function_name)
         @self.http_type(http_type='asgi')
         @self.route(methods=(method for method in HttpMethod),
                     auth_level=self.auth_level,
@@ -3395,21 +3418,25 @@ async def http_app_func(req: HttpRequest, context: Context):
 
 class WsgiFunctionApp(ExternalHttpFunctionApp):
     def __init__(self, app,
-                 http_auth_level: Union[AuthLevel, str] = AuthLevel.FUNCTION):
+                 http_auth_level: Union[AuthLevel, str] = AuthLevel.FUNCTION,
+                 function_name: str = 'http_app_func'):
         """Constructor of :class:`WsgiFunctionApp` object.
 
         :param app: wsgi app object.
+        :param function_name: function name
         """
         super().__init__(auth_level=http_auth_level)
-        self._add_http_app(WsgiMiddleware(app))
+        self._add_http_app(WsgiMiddleware(app), function_name)
 
     def _add_http_app(self,
                       http_middleware: Union[
-                          AsgiMiddleware, WsgiMiddleware]) -> None:
+                          AsgiMiddleware, WsgiMiddleware],
+                      function_name: str = 'http_app_func') -> None:
         """Add a Wsgi app integrated http function.
 
         :param http_middleware: :class:`WsgiMiddleware`
                                 or class:`AsgiMiddleware` instance.
+        :param function_name: name for the function
 
         :return: None
         """
@@ -3419,6 +3446,7 @@ def _add_http_app(self,
 
         wsgi_middleware: WsgiMiddleware = http_middleware
 
+        @self.function_name(function_name)
         @self.http_type(http_type='wsgi')
         @self.route(methods=(method for method in HttpMethod),
                     auth_level=self.auth_level,

tests/decorators/test_dapr.py

@@ -24,7 +24,7 @@ def test_dapr_service_invocation_trigger_default_args(self):
 
         @app.dapr_service_invocation_trigger(arg_name="req",
                                              method_name="dummy_method_name")
-        def dummy():
+        def test_dapr_service_invocation_trigger_default_args():
             pass
 
         func = self._get_user_function(app)
@@ -50,7 +50,7 @@ def test_dapr_binding_trigger_default_args(self):
 
         @app.dapr_binding_trigger(arg_name="req",
                                   binding_name="dummy_binding_name")
-        def dummy():
+        def test_dapr_binding_trigger_default_args():
             pass
 
         func = self._get_user_function(app)
@@ -73,7 +73,7 @@ def test_dapr_topic_trigger_default_args(self):
                                 pub_sub_name="dummy_pub_sub_name",
                                 topic="dummy_topic",
                                 route="/dummy_route")
-        def dummy():
+        def test_dapr_topic_trigger_default_args():
             pass
 
         func = self._get_user_function(app)
@@ -99,7 +99,7 @@ def test_dapr_state_input_binding(self):
         @app.dapr_state_input(arg_name="in",
                               state_store="dummy_state_store",
                               key="dummy_key")
-        def dummy():
+        def test_dapr_state_input_binding():
             pass
 
         func = self._get_user_function(app)
@@ -125,7 +125,7 @@ def test_dapr_secret_input_binding(self):
                                secret_store_name="dummy_secret_store_name",
                                key="dummy_key",
                                metadata="dummy_metadata")
-        def dummy():
+        def test_dapr_secret_input_binding():
             pass
 
         func = self._get_user_function(app)
@@ -151,7 +151,7 @@ def test_dapr_state_output_binding(self):
         @app.dapr_state_output(arg_name="out",
                                state_store="dummy_state_store",
                                key="dummy_key")
-        def dummy():
+        def test_dapr_state_output_binding():
             pass
 
         func = self._get_user_function(app)
@@ -177,7 +177,7 @@ def test_dapr_invoke_output_binding(self):
                                 app_id="dummy_app_id",
                                 method_name="dummy_method_name",
                                 http_verb="dummy_http_verb")
-        def dummy():
+        def test_dapr_invoke_output_binding():
             pass
 
         func = self._get_user_function(app)
@@ -203,7 +203,7 @@ def test_dapr_publish_output_binding(self):
         @app.dapr_publish_output(arg_name="out",
                                  pub_sub_name="dummy_pub_sub_name",
                                  topic="dummy_topic")
-        def dummy():
+        def test_dapr_publish_output_binding():
             pass
 
         func = self._get_user_function(app)
@@ -228,7 +228,7 @@ def test_dapr_binding_output_binding(self):
         @app.dapr_binding_output(arg_name="out",
                                  binding_name="dummy_binding_name",
                                  operation="dummy_operation")
-        def dummy():
+        def test_dapr_binding_output_binding():
             pass
 
         func = self._get_user_function(app)