Skip to content

gh-116040: [Enum] fix by-value calls when second value is falsey; e.g. Cardinal(1, 0) #116072

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Mar 7, 2024
+35 −4
Merged

gh-116040: [Enum] fix by-value calls when second value is falsey; e.g. Cardinal(1, 0) #116072

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
a5828a6
fix by-value calls when second value is falsey; e.g. Cardinal(1, 0)
ethanfurman Feb 28, 2024
f04a765
Merge branch 'main' into enum-zero_not_none
ethanfurman Feb 28, 2024
248bd2c
address review comments
ethanfurman Mar 4, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 11 additions & 4 deletions Lib/enum.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -162,6 +162,13 @@ def _dedent(text):
lines[j] = l[i:]
return '\n'.join(lines)

class _not_given:
def __repr__(self):
return('<not given>')
def __bool__(self):
return False
Comment on lines +168 to +169
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is it needed?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yes, or the or None at line 730 will fail.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Perhaps it should not take the boolean value there at first place, but use is not _not_given? I suspected that it can produce weird results if the second value is false and type is given.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm not sure what you mean -- is "second value" the names parameter? If it's falsey and a type is given, a new empty enum is created (which is appropriate).

_not_given = _not_given()

class _auto_null:
def __repr__(self):
return '_auto_null'
Expand Down Expand Up @@ -680,7 +687,7 @@ def __bool__(cls):
"""
return True

def __call__(cls, value, names=None, *values, module=None, qualname=None, type=None, start=1, boundary=None):
def __call__(cls, value, names=_not_given, *values, module=None, qualname=None, type=None, start=1, boundary=None):
"""
Either returns an existing member, or creates a new enum class.

Expand Down Expand Up @@ -709,18 +716,18 @@ def __call__(cls, value, names=None, *values, module=None, qualname=None, type=N
"""
if cls._member_map_:
# simple value lookup if members exist
if names:
if names is not _not_given:
value = (value, names) + values
return cls.__new__(cls, value)
# otherwise, functional API: we're creating a new Enum type
if names is None and type is None:
if names is _not_given and type is None:
# no body? no data-type? possibly wrong usage
raise TypeError(
f"{cls} has no members; specify `names=()` if you meant to create a new, empty, enum"
)
return cls._create_(
class_name=value,
names=names,
names=names or None,
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Add tests for something like:

  • Enum('empty_enum', '')
  • Enum('empty_enum', [])
  • Enum('empty_enum', {})
  • Enum('empty_enum', '', type=int)
  • Enum('empty_enum', [], type=int)
  • Enum('empty_enum', {}, type=int)

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Done.

module=module,
qualname=qualname,
type=type,
Expand Down
23 changes: 23 additions & 0 deletions Lib/test/test_enum.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3409,6 +3409,15 @@ def __new__(cls, int_value, *value_aliases):
self.assertIs(Types(2), Types.NetList)
self.assertIs(Types('nl'), Types.NetList)

def test_second_tuple_item_is_falsey(self):
class Cardinal(Enum):
RIGHT = (1, 0)
UP = (0, 1)
LEFT = (-1, 0)
DOWN = (0, -1)
self.assertIs(Cardinal(1, 0), Cardinal.RIGHT)
self.assertIs(Cardinal(-1, 0), Cardinal.LEFT)

def test_no_members(self):
with self.assertRaisesRegex(
TypeError,
Expand All @@ -3421,6 +3430,20 @@ def test_no_members(self):
):
Flag(7)

def test_empty_names(self):
for nothing, e_type in (
('', None),
('', int),
([], None),
([], int),
({}, None),
({}, int),
):
Comment on lines +3434 to +3441
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It could perhaps be clearer with nested loops.

for nothing in '', [], {}:
    for e_type in None, int:
        ...

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Good point.

empty_enum = Enum('empty_enum', nothing, type=e_type)
self.assertEqual(len(empty_enum), 0)
self.assertRaises(TypeError, 'has no members', empty_enum, 0)
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It raises a TypeError because you try to call 'has no members'(empty_enum, 0).

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Gah. Changed to assertRaisesRegex.



class TestOrder(unittest.TestCase):
"test usage of the `_order_` attribute"

Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2024-02-28-13-10-17.gh-issue-116040.wDidHd.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
[Enum] fix by-value calls when second value is falsey; e.g. Cardinal(1, 0)