Repository: Stewori/pytypes

Issue:
typechecked(string) should have more consistent return type
Currently if you call `typechecked` on a string module name, it has case-by-case behavior to sometimes return the original string and sometimes return the resolved module:
```python
typechecked('requests') → <module 'requests'>
typechecked('requests') → 'requests'
```

Could we simplify to make it unconditionally return the value that was passed in, str→str, module→module, class→class, etc?

Discussion:

Patch:
diff --git a/pytypes/typechecker.py b/pytypes/typechecker.py
index a0cd92b..b6b4342 100644
--- a/pytypes/typechecker.py
+++ b/pytypes/typechecker.py
@@ -964,15 +964,19 @@ def typechecked_module(md, force_recursive = False):
     """
     if not pytypes.checking_enabled:
         return md
+    # Save input to return original string if input was a string.
+    md_arg = md
     if isinstance(md, str):
         if md in sys.modules:
             md = sys.modules[md]
             if md is None:
-                return md
+                return md_arg
         elif md in _pending_modules:
             # if import is pending, we just store this call for later
             _pending_modules[md].append(lambda t: typechecked_module(t, True))
-            return md
+            return md_arg
+        else:
+            raise KeyError('Found no module {!r} to typecheck'.format(md))
     assert(ismodule(md))
     if md.__name__ in _pending_modules:
             # if import is pending, we just store this call for later
@@ -981,7 +985,7 @@ def typechecked_module(md, force_recursive = False):
             # todo: Issue warning here that not the whole module might be covered yet
     if md.__name__ in _fully_typechecked_modules and \
             _fully_typechecked_modules[md.__name__] == len(md.__dict__):
-        return md
+        return md_arg
     # To play it safe we avoid to modify the dict while iterating over it,
     # so we previously cache keys.
     # For this we don't use keys() because of Python 3.
@@ -997,7 +1001,7 @@ def typechecked_module(md, force_recursive = False):
                 typechecked_class(memb, force_recursive, force_recursive)
     if not md.__name__ in _pending_modules:
         _fully_typechecked_modules[md.__name__] = len(md.__dict__)
-    return md
+    return md_arg
 
 
 def typechecked(memb):


Test patch:
diff --git a/tests/test_typechecker.py b/tests/test_typechecker.py
index fc4483d..60546b5 100644
--- a/tests/test_typechecker.py
+++ b/tests/test_typechecker.py
@@ -2651,8 +2651,14 @@ class TestTypecheck_module(unittest.TestCase):
     def test_function_py2(self):
         from testhelpers import modulewide_typecheck_testhelper_py2 as mth
         self.assertEqual(mth.testfunc(3, 2.5, 'abcd'), (9, 7.5))
+        with self.assertRaises(KeyError):
+            pytypes.typechecked_module('nonexistent123')
         self.assertEqual(mth.testfunc(3, 2.5, 7), (9, 7.5)) # would normally fail
-        pytypes.typechecked_module(mth)
+        module_name = 'testhelpers.modulewide_typecheck_testhelper_py2'
+        returned_mth = pytypes.typechecked_module(module_name)
+        self.assertEqual(returned_mth, module_name)
+        returned_mth = pytypes.typechecked_module(mth)
+        self.assertEqual(returned_mth, mth)
         self.assertEqual(mth.testfunc(3, 2.5, 'abcd'), (9, 7.5))
         self.assertRaises(InputTypeError, lambda: mth.testfunc(3, 2.5, 7))
 
@@ -2662,7 +2668,8 @@ class TestTypecheck_module(unittest.TestCase):
         from testhelpers import modulewide_typecheck_testhelper as mth
         self.assertEqual(mth.testfunc(3, 2.5, 'abcd'), (9, 7.5))
         self.assertEqual(mth.testfunc(3, 2.5, 7), (9, 7.5)) # would normally fail
-        pytypes.typechecked_module(mth)
+        returned_mth = pytypes.typechecked_module(mth)
+        self.assertEqual(returned_mth, mth)
         self.assertEqual(mth.testfunc(3, 2.5, 'abcd'), (9, 7.5))
         self.assertRaises(InputTypeError, lambda: mth.testfunc(3, 2.5, 7))