add deprecation.argument_removed

2 files changed, 38 insertions, 0 deletions

diff --git a/logilab/common/deprecation.py b/logilab/common/deprecation.py
index 577aee7..4aaeba3 100644
--- a/logilab/common/deprecation.py
+++ b/logilab/common/deprecation.py
@@ -268,6 +268,33 @@ def argument_renamed(old_name, new_name):
     return _wrap
 
 
+def argument_removed(old_argument_name):
+    """
+    callable decorator to allow getting backward compatibility for renamed keyword arguments.
+
+    >>> @argument_removed("old")
+    ... def some_function(new):
+    ...     return new
+    >>> some_function(old=42)
+    sample.py:15: DeprecationWarning: argument old of callable some_function has been renamed and is deprecated, use keyword argument new instead
+      some_function(old=42)
+    42
+    """
+    def _wrap(func):
+        @wraps(func)
+        def check_kwargs(*args, **kwargs):
+            if old_argument_name in kwargs:
+                warn(f"argument {old_argument_name} of callable {func.__name__} has been removed and is "
+                     f"deprecated", stacklevel=2)
+                del kwargs[old_argument_name]
+
+            return func(*args, **kwargs)
+
+        return check_kwargs
+
+    return _wrap
+
+
 def renamed(old_name, new_function):
     """use to tell that a callable has been renamed.
 
diff --git a/test/unittest_deprecation.py b/test/unittest_deprecation.py
index 7881252..60b10f4 100644
--- a/test/unittest_deprecation.py
+++ b/test/unittest_deprecation.py
@@ -107,6 +107,17 @@ class RawInputTC(TestCase):
         with self.assertRaises(ValueError):
             some_function(new=42, old=42)
 
+    def test_argument_removed(self):
+        @deprecation.argument_removed("old")
+        def some_function(new):
+            return new
+
+        self.assertEqual(some_function(new=42), 42)
+        self.assertEqual(some_function(new=10, old=20), 10)
+        self.assertEqual(self.messages,
+                         ['argument old of callable some_function has been removed and is '
+                          'deprecated'])
+
     def test_renamed(self):
         def any_func():
             pass