FunctionRegister.get_functions is not idempotent

[akonovalov-epam]

Is your question related to a specific version? If so, please specify:

azure-functions==1.23.0

What binding does your question apply to, if any? (e.g. Blob Trigger, Event Hub Binding, etc)

It relates to azure.functions.decorators.function_app.FunctionRegister class, to be precise to its method get_functions

Question

Hello!
I recently found that azure.functions.decorators.function_app.FunctionRegister.get_functions method, if invoked twice, throws an error like "ValueError: Function DummyFunctionName does not have a unique function name. Please change @app.function_name() or the function method name to be unique.", even if function is truly unique. This happens because "validate_function_names" internally populates "functions_bindings", but doesn't cleanup before or after populating, therefore on second run it throws error that function name is not unique

    def validate_function_names(self, functions: List[Function]):
        if not self.functions_bindings:
            self.functions_bindings = {}  # HERE, but only if originally None
        for function in functions:
            function_name = function.get_function_name()
            if function_name in self.functions_bindings:
                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.functions_bindings[function_name] = True

and it looks like it supposed to be like

    def validate_function_names(self, functions: List[Function]):
        functions_bindings = {}  # HERE: list of already checked functions creates every time on invocation
        for function in functions:
            function_name = function.get_function_name()
            if function_name in functions_bindings:
                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.functions_bindings[function_name] = True   # NOTE: lookup remains same

However, I'm a bit confused if it is actual bug, and, if yes, how and where I can create PR to fix it?

Thank you!