From 8fa18cd61b6fc6192662f20890c2dd5bfd998eb0 Mon Sep 17 00:00:00 2001
From: xdrm-brackets <xdrm.brackets.dev@gmail.com>
Date: Sat, 4 Apr 2020 10:02:48 +0200
Subject: [PATCH] enforce dynamic signature check: no input struct allowed when
 no input is specified

---
 dynamic/errors.go    | 3 +++
 dynamic/spec.go      | 3 +++
 dynamic/spec_test.go | 4 ++--
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/dynamic/errors.go b/dynamic/errors.go
index f8260c3..9467bcf 100644
--- a/dynamic/errors.go
+++ b/dynamic/errors.go
@@ -17,6 +17,9 @@ const ErrNoServiceForHandler = cerr("no service found for this handler")
 // ErrMissingHandlerArgumentParam - missing params arguments for handler
 const ErrMissingHandlerArgumentParam = cerr("missing handler argument : parameter struct")
 
+// ErrUnexpectedInput - input argument is not expected
+const ErrUnexpectedInput = cerr("unexpected input struct")
+
 // ErrMissingHandlerOutput - missing output for handler
 const ErrMissingHandlerOutput = cerr("handler must have at least 1 output")
 
diff --git a/dynamic/spec.go b/dynamic/spec.go
index 9e0871e..ee6fd06 100644
--- a/dynamic/spec.go
+++ b/dynamic/spec.go
@@ -44,6 +44,9 @@ func (s spec) checkInput(fnv reflect.Value) error {
 
 	// no input -> ok
 	if len(s.Input) == 0 {
+		if fnt.NumIn() > 0 {
+			return ErrUnexpectedInput
+		}
 		return nil
 	}
 
diff --git a/dynamic/spec_test.go b/dynamic/spec_test.go
index 535d9e3..0ce92bc 100644
--- a/dynamic/spec_test.go
+++ b/dynamic/spec_test.go
@@ -21,11 +21,11 @@ func TestInputCheck(t *testing.T) {
 			Fn:    func() {},
 			Err:   nil,
 		},
-		// func can have any arguments if not specified
+		// func must have noarguments if none specified
 		{
 			Input: map[string]reflect.Type{},
 			Fn:    func(int, string) {},
-			Err:   nil,
+			Err:   ErrUnexpectedInput,
 		},
 		// missing input struct in func
 		{