[decorators] monkeypatch should build a method type closes #73920

3 files changed, 50 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index c4f87cb..8bc7f3e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,11 +1,10 @@
 ChangeLog for logilab.common
 ============================
 
-	--
-    * modutils: allow overriding of _getobj by suppressing mangling
-
 --
-    * daemon: call initgroups/setgid before setuid
+    * daemon: call initgroups/setgid before setuid (closes #74173)
+    * decorators: @monkeypatch should produce a method object (closes #73920)
+    * modutils: allow overriding of _getobj by suppressing mangling
 
 2011-08-05  --  0.56.1
     * clcommands: #72450 --rc-file option doesn't work
diff --git a/decorators.py b/decorators.py
index 39144d1..7bb08fc 100644
--- a/decorators.py
+++ b/decorators.py
@@ -209,7 +209,7 @@ def locked(acquire, release):
 
 
 def monkeypatch(klass, methodname=None):
-    """Decorator extending class with the decorated function
+    """Decorator extending class with the decorated callable
     >>> class A:
     ...     pass
     >>> @monkeypatch(A)
@@ -227,6 +227,17 @@ def monkeypatch(klass, methodname=None):
     12
     """
     def decorator(func):
-        setattr(klass, methodname or func.__name__, func)
+        try:
+            name = methodname or func.__name__
+        except AttributeError:
+            raise AttributeError('%s has no __name__ attribute: '
+                                 'you should provide an explicit `methodname`'
+                                 % func)
+        if callable(func):
+            setattr(klass, name, types.MethodType(func, None, klass))
+        else:
+            # likely a property
+            # this is quite borderline but usage already in the wild ...
+            setattr(klass, name, func)
         return func
     return decorator
diff --git a/test/unittest_decorators.py b/test/unittest_decorators.py
index 75261c9..355e934 100644
--- a/test/unittest_decorators.py
+++ b/test/unittest_decorators.py
@@ -17,12 +17,46 @@
 # with logilab-common.  If not, see <http://www.gnu.org/licenses/>.
 """unit tests for the decorators module
 """
+import types
 
 from logilab.common.testlib import TestCase, unittest_main
 from logilab.common.decorators import monkeypatch, cached, clear_cache, copy_cache
 
 class DecoratorsTC(TestCase):
 
+    def test_monkeypatch_instance_method(self):
+        class MyClass: pass
+        @monkeypatch(MyClass)
+        def meth1(self):
+            return 12
+        class XXX(object):
+            @monkeypatch(MyClass)
+            def meth2(self):
+                return 12
+        self.assertTrue(isinstance(MyClass.meth1, types.MethodType))
+        self.assertTrue(isinstance(MyClass.meth2, types.MethodType))
+
+    def test_monkeypatch_callable_non_callable(self):
+        tester = self
+        class MyClass: pass
+        @monkeypatch(MyClass, methodname='prop1')
+        @property
+        def meth1(self):
+            return 12
+        class XXX(object):
+            def __call__(self, other):
+                tester.assertTrue(isinstance(other, MyClass))
+                return 12
+        try:
+            monkeypatch(MyClass)(XXX())
+        except AttributeError, err:
+            self.assertTrue(str(err).endswith('has no __name__ attribute: you should provide an explicit `methodname`'))
+        monkeypatch(MyClass, 'foo')(XXX())
+        self.assertTrue(isinstance(MyClass.prop1, property))
+        self.assertTrue(callable(MyClass.foo))
+        self.assertEqual(MyClass().prop1, 12)
+        self.assertEqual(MyClass().foo(), 12)
+
     def test_monkeypatch_with_same_name(self):
         class MyClass: pass
         @monkeypatch(MyClass)