[Python-checkins] bpo-41403: Improve error message for invalid mock target (GH-30833) (GH-30834)

[iritkatriel]

https://github.com/python/cpython/commit/e3ade66ec575e0cb4882cfdff155ef962e67c837
commit: e3ade66ec575e0cb4882cfdff155ef962e67c837
branch: 3.10
author: Irit Katriel <1055913+iritkatriel at users.noreply.github.com>
committer: iritkatriel <1055913+iritkatriel at users.noreply.github.com>
date: 2022-01-23T19:34:43Z
summary:

bpo-41403: Improve error message for invalid mock target (GH-30833) (GH-30834)

(cherry picked from commit f7955a82e36d4c32ebdd7b7707cdf0e6ffa7a418)

files:
A Misc/NEWS.d/next/Library/2022-01-23-18-04-45.bpo-41403.SgoHqV.rst
M Lib/unittest/mock.py
M Lib/unittest/test/testmock/testpatch.py

diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py
index 6226bd4bc0c19..7152f86ed9694 100644
--- a/Lib/unittest/mock.py
+++ b/Lib/unittest/mock.py
@@ -1602,9 +1602,9 @@ def stop(self):
 def _get_target(target):
     try:
         target, attribute = target.rsplit('.', 1)
-    except (TypeError, ValueError):
-        raise TypeError("Need a valid target to patch. You supplied: %r" %
-                        (target,))
+    except (TypeError, ValueError, AttributeError):
+        raise TypeError(
+            f"Need a valid target to patch. You supplied: {target!r}")
     getter = lambda: _importer(target)
     return getter, attribute
 
diff --git a/Lib/unittest/test/testmock/testpatch.py b/Lib/unittest/test/testmock/testpatch.py
index 233a5afffaed4..8ab63a1317d3d 100644
--- a/Lib/unittest/test/testmock/testpatch.py
+++ b/Lib/unittest/test/testmock/testpatch.py
@@ -1933,8 +1933,13 @@ def test(mock):
 
 
     def test_invalid_target(self):
-        with self.assertRaises(TypeError):
-            patch('')
+        class Foo:
+            pass
+
+        for target in ['', 12, Foo()]:
+            with self.subTest(target=target):
+                with self.assertRaises(TypeError):
+                    patch(target)
 
 
     def test_cant_set_kwargs_when_passing_a_mock(self):
diff --git a/Misc/NEWS.d/next/Library/2022-01-23-18-04-45.bpo-41403.SgoHqV.rst b/Misc/NEWS.d/next/Library/2022-01-23-18-04-45.bpo-41403.SgoHqV.rst
new file mode 100644
index 0000000000000..ede159b25641f
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-01-23-18-04-45.bpo-41403.SgoHqV.rst
@@ -0,0 +1,3 @@
+Make :meth:`mock.patch` raise a :exc:`TypeError` with a relevant error
+message on invalid arg. Previously it allowed a cryptic
+:exc:`AttributeError` to escape.