From a1a0e5b711e6838ee8a120d410cb512362faf131 Mon Sep 17 00:00:00 2001
From: Laurent Peuch <cortex@worlddomination.be>
Date: Wed, 26 Aug 2020 17:26:22 +0200
Subject: fix(deprecation): stacked decorators breaks getting the real callable
 __name__ attribute

---
 logilab/common/deprecation.py | 30 ++++++++++++++++++++++++------
 test/test_deprecation.py      | 25 +++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/logilab/common/deprecation.py b/logilab/common/deprecation.py
index af23f07..18027d7 100644
--- a/logilab/common/deprecation.py
+++ b/logilab/common/deprecation.py
@@ -25,6 +25,24 @@ from warnings import warn
 from functools import WRAPPER_ASSIGNMENTS, WRAPPER_UPDATES
 
 
+def get_real__name__(some_callable):
+    """
+    This is another super edge magic case which is needed because we uses
+    lazy_wraps because of logilab.common.modutils.LazyObject and because
+    __name__ has special behavior and doesn't work like a normal attribute and
+    that __getattribute__ of lazy_wraps is bypassed.
+
+    Therefor, to get the real callable name when several lazy_wrapped
+    decorator are used we need to travers the __wrapped__ attributes chain.
+    """
+
+    targeted_callable = some_callable
+    while hasattr(targeted_callable, "__wrapped__"):
+        targeted_callable = targeted_callable.__wrapped__  # type: ignore
+
+    return targeted_callable.__name__
+
+
 def lazy_wraps(wrapped):
     """
     This is the equivalent of the @wraps decorator of functools except it won't
@@ -142,8 +160,8 @@ def callable_renamed(old_name, new_function, version=None):
     def wrapped(*args, **kwargs):
         send_warning(
             (
-                f"{old_name} has been renamed and is deprecated, uses {new_function.__name__} "
-                f"instead"
+                f"{old_name} has been renamed and is deprecated, uses "
+                f"{get_real__name__(new_function)} instead"
             ),
             stacklevel=3,
             version=version,
@@ -175,7 +193,7 @@ def argument_removed(old_argument_name, version=None):
         def check_kwargs(*args, **kwargs):
             if old_argument_name in kwargs:
                 send_warning(
-                    f"argument {old_argument_name} of callable {func.__name__} has been "
+                    f"argument {old_argument_name} of callable {get_real__name__(func)} has been "
                     f"removed and is deprecated",
                     stacklevel=3,
                     version=version,
@@ -202,7 +220,7 @@ def callable_deprecated(reason=None, version=None, stacklevel=2):
         def wrapped(*args, **kwargs):
             message = reason or 'The function "%s" is deprecated'
             if "%s" in message:
-                message %= func.__name__
+                message %= get_real__name__(func)
 
             send_warning(message, version, stacklevel + 1, module_name=func.__module__)
             return func(*args, **kwargs)
@@ -306,14 +324,14 @@ def argument_renamed(old_name, new_name, version=None):
         def check_kwargs(*args, **kwargs):
             if old_name in kwargs and new_name in kwargs:
                 raise ValueError(
-                    f"argument {old_name} of callable {func.__name__} has been "
+                    f"argument {old_name} of callable {get_real__name__(func)} has been "
                     f"renamed to {new_name} but you are both using {old_name} and "
                     f"{new_name} has keyword arguments, only uses {new_name}"
                 )
 
             if old_name in kwargs:
                 send_warning(
-                    f"argument {old_name} of callable {func.__name__} has been renamed "
+                    f"argument {old_name} of callable {get_real__name__(func)} has been renamed "
                     f"and is deprecated, use keyword argument {new_name} instead",
                     stacklevel=3,
                     version=version,
diff --git a/test/test_deprecation.py b/test/test_deprecation.py
index 3cbce9c..2508208 100644
--- a/test/test_deprecation.py
+++ b/test/test_deprecation.py
@@ -143,6 +143,31 @@ class RawInputTC(TestCase):
         # by default.
         # See: https://forge.extranet.logilab.fr/cubicweb/cubicweb/blob/3.24.0/cubicweb/schemas/__init__.py#L51 # noqa
 
+    def test_lazy_wraps_function_name(self):
+        """
+        Avoid conflict from lazy_wraps where __name__ isn't correctly set on
+        the wrapper from the wrapped and we end up with the name of the wrapper
+        instead of the wrapped.
+
+        Like here it would fail if "check_kwargs" is the name of the new
+        function instead of new_function_name, this is because the wrapper in
+        argument_renamed is called check_kwargs and doesn't transmit the
+        __name__ of the wrapped (new_function_name) correctly.
+        """
+
+        @deprecation.argument_renamed(old_name="a", new_name="b")
+        def new_function_name(b):
+            pass
+
+        old_function_name = deprecation.callable_renamed(
+            old_name="old_function_name", new_function=new_function_name
+        )
+        old_function_name(None)
+
+        assert "old_function_name" in self.messages[0]
+        assert "new_function_name" in self.messages[0]
+        assert "check_kwargs" not in self.messages[0]
+
     def test_attribute_renamed(self):
         @deprecation.attribute_renamed(old_name="old", new_name="new")
         class SomeClass:
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