From: Ethan Furman <ethan@stoneleaf.us>
Date: Fri, 25 Oct 2024 23:03:52 +0000 (-0700)
Subject: [3.12] gh-125259: Fix error notes removal in enum initialization (GH-125647) (GH... 
X-Git-Tag: v3.12.8~168
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=d0b2fa4804eb7edf08fd6d97fa615e190d679d81;p=thirdparty%2FPython%2Fcpython.git

[3.12] gh-125259: Fix error notes removal in enum initialization (GH-125647) (GH-125953)

(cherry picked from commit 34653bba644aa5481613f398153757d7357e39ea)

Co-authored-by: Mario Šaško <mariosasko777@gmail.com>
---

diff --git a/Lib/enum.py b/Lib/enum.py
index d9859b3c0a9f..eaa517e2fbc3 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -592,19 +592,13 @@ class EnumType(type):
         classdict['_all_bits_'] = 0
         classdict['_inverted_'] = None
         try:
-            exc = None
             enum_class = super().__new__(metacls, cls, bases, classdict, **kwds)
         except Exception as e:
-            # since 3.12 the line "Error calling __set_name__ on '_proto_member' instance ..."
-            # is tacked on to the error instead of raising a RuntimeError
-            # recreate the exception to discard
-            exc = type(e)(str(e))
-            exc.__cause__ = e.__cause__
-            exc.__context__ = e.__context__
-            tb = e.__traceback__
-        if exc is not None:
-            raise exc.with_traceback(tb)
-        #
+            # since 3.12 the note "Error calling __set_name__ on '_proto_member' instance ..."
+            # is tacked on to the error instead of raising a RuntimeError, so discard it
+            if hasattr(e, '__notes__'):
+                del e.__notes__
+            raise
         # update classdict with any changes made by __init_subclass__
         classdict.update(enum_class.__dict__)
         #
diff --git a/Lib/test/test_enum.py b/Lib/test/test_enum.py
index aff5b7f68f01..2e50ae0fe965 100644
--- a/Lib/test/test_enum.py
+++ b/Lib/test/test_enum.py
@@ -1852,6 +1852,25 @@ class TestSpecial(unittest.TestCase):
             class Wrong(Enum, str):
                 NotHere = 'error before this point'
 
+    def test_raise_custom_error_on_creation(self):
+        class InvalidRgbColorError(ValueError):
+            def __init__(self, r, g, b):
+                self.r = r
+                self.g = g
+                self.b = b
+                super().__init__(f'({r}, {g}, {b}) is not a valid RGB color')
+
+        with self.assertRaises(InvalidRgbColorError):
+            class RgbColor(Enum):
+                RED = (255, 0, 0)
+                GREEN = (0, 255, 0)
+                BLUE = (0, 0, 255)
+                INVALID = (256, 0, 0)
+
+                def __init__(self, r, g, b):
+                    if not all(0 <= val <= 255 for val in (r, g, b)):
+                        raise InvalidRgbColorError(r, g, b)
+
     def test_intenum_transitivity(self):
         class number(IntEnum):
             one = 1
diff --git a/Misc/NEWS.d/next/Library/2024-10-17-16-10-29.gh-issue-125259.oMew0c.rst b/Misc/NEWS.d/next/Library/2024-10-17-16-10-29.gh-issue-125259.oMew0c.rst
new file mode 100644
index 000000000000..4fa6330abea5
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-10-17-16-10-29.gh-issue-125259.oMew0c.rst
@@ -0,0 +1 @@
+Fix the notes removal logic for errors thrown in enum initialization.