[Python-checkins] gh-100039: enhance __signature__ to work with str and callables (GH-100168)
ethanfurman
webhook-mailer at python.org
Fri Dec 16 15:30:53 EST 2022
https://github.com/python/cpython/commit/a5a7cea202d34ca699d9594d428ba527ef7ff2ce
commit: a5a7cea202d34ca699d9594d428ba527ef7ff2ce
branch: main
author: Ethan Furman <ethan at stoneleaf.us>
committer: ethanfurman <ethan at stoneleaf.us>
date: 2022-12-16T12:30:47-08:00
summary:
gh-100039: enhance __signature__ to work with str and callables (GH-100168)
Callables should be either class- or static-methods.
Enum now uses the classmethod version to greatly improve the help
given for enums and flags.
files:
A Misc/NEWS.d/next/Library/2022-12-10-20-52-28.gh-issue-100039.zDqjT4.rst
M Lib/enum.py
M Lib/inspect.py
M Lib/test/test_enum.py
M Lib/test/test_inspect.py
diff --git a/Lib/enum.py b/Lib/enum.py
index a0cad066dc23..21f63881d78d 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -685,7 +685,7 @@ def __new__(metacls, cls, bases, classdict, *, boundary=None, _simple=False, **k
'member order does not match _order_:\n %r\n %r'
% (enum_class._member_names_, _order_)
)
-
+ #
return enum_class
def __bool__(cls):
@@ -1083,6 +1083,13 @@ class Enum(metaclass=EnumType):
attributes -- see the documentation for details.
"""
+ @classmethod
+ def __signature__(cls):
+ if cls._member_names_:
+ return '(*values)'
+ else:
+ return '(new_class_name, /, names, *, module=None, qualname=None, type=None, start=1, boundary=None)'
+
def __new__(cls, value):
# all enum instances are actually created during class construction
# without calling this method; this method is called by the metaclass'
diff --git a/Lib/inspect.py b/Lib/inspect.py
index e165937e448a..e92c355220fd 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -2443,10 +2443,18 @@ def _signature_from_callable(obj, *,
pass
else:
if sig is not None:
+ # since __text_signature__ is not writable on classes, __signature__
+ # may contain text (or be a callable that returns text);
+ # if so, convert it
+ o_sig = sig
+ if not isinstance(sig, (Signature, str)) and callable(sig):
+ sig = sig()
+ if isinstance(sig, str):
+ sig = _signature_fromstr(sigcls, obj, sig)
if not isinstance(sig, Signature):
raise TypeError(
'unexpected object {!r} in __signature__ '
- 'attribute'.format(sig))
+ 'attribute'.format(o_sig))
return sig
try:
diff --git a/Lib/test/test_enum.py b/Lib/test/test_enum.py
index d876c8e5fb77..1e653e94f6b5 100644
--- a/Lib/test/test_enum.py
+++ b/Lib/test/test_enum.py
@@ -4259,7 +4259,7 @@ class TestEnumTypeSubclassing(unittest.TestCase):
Help on class Color in module %s:
class Color(enum.Enum)
- | Color(value, names=None, *values, module=None, qualname=None, type=None, start=1, boundary=None)
+ | Color(*values)
|
| Method resolution order:
| Color
@@ -4315,7 +4315,7 @@ class Color(enum.Enum)
Help on class Color in module %s:
class Color(enum.Enum)
- | Color(value, names=None, *values, module=None, qualname=None, type=None, start=1)
+ | Color(*values)
|
| Method resolution order:
| Color
@@ -4462,6 +4462,27 @@ def test_inspect_classify_class_attrs(self):
if failed:
self.fail("result does not equal expected, see print above")
+ def test_inspect_signatures(self):
+ from inspect import signature, Signature, Parameter
+ self.assertEqual(
+ signature(Enum),
+ Signature([
+ Parameter('new_class_name', Parameter.POSITIONAL_ONLY),
+ Parameter('names', Parameter.POSITIONAL_OR_KEYWORD),
+ Parameter('module', Parameter.KEYWORD_ONLY, default=None),
+ Parameter('qualname', Parameter.KEYWORD_ONLY, default=None),
+ Parameter('type', Parameter.KEYWORD_ONLY, default=None),
+ Parameter('start', Parameter.KEYWORD_ONLY, default=1),
+ Parameter('boundary', Parameter.KEYWORD_ONLY, default=None),
+ ]),
+ )
+ self.assertEqual(
+ signature(enum.FlagBoundary),
+ Signature([
+ Parameter('values', Parameter.VAR_POSITIONAL),
+ ]),
+ )
+
def test_test_simple_enum(self):
@_simple_enum(Enum)
class SimpleColor:
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 2b7977b1648f..0f8217ba3b75 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -3614,6 +3614,38 @@ def foo(): pass
self.assertEqual(signature_func(foo), inspect.Signature())
self.assertEqual(inspect.get_annotations(foo), {})
+ def test_signature_as_str(self):
+ self.maxDiff = None
+ class S:
+ __signature__ = '(a, b=2)'
+
+ self.assertEqual(self.signature(S),
+ ((('a', ..., ..., 'positional_or_keyword'),
+ ('b', 2, ..., 'positional_or_keyword')),
+ ...))
+
+ def test_signature_as_callable(self):
+ # __signature__ should be either a staticmethod or a bound classmethod
+ class S:
+ @classmethod
+ def __signature__(cls):
+ return '(a, b=2)'
+
+ self.assertEqual(self.signature(S),
+ ((('a', ..., ..., 'positional_or_keyword'),
+ ('b', 2, ..., 'positional_or_keyword')),
+ ...))
+
+ class S:
+ @staticmethod
+ def __signature__():
+ return '(a, b=2)'
+
+ self.assertEqual(self.signature(S),
+ ((('a', ..., ..., 'positional_or_keyword'),
+ ('b', 2, ..., 'positional_or_keyword')),
+ ...))
+
class TestParameterObject(unittest.TestCase):
def test_signature_parameter_kinds(self):
diff --git a/Misc/NEWS.d/next/Library/2022-12-10-20-52-28.gh-issue-100039.zDqjT4.rst b/Misc/NEWS.d/next/Library/2022-12-10-20-52-28.gh-issue-100039.zDqjT4.rst
new file mode 100644
index 000000000000..d56643f7e871
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-12-10-20-52-28.gh-issue-100039.zDqjT4.rst
@@ -0,0 +1 @@
+Improve signatures for enums and flags.
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