Movatterモバイル変換


[0]ホーム

URL:


Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

Sign up
Appearance settings

gh-143715: Deprecate incomplete initialization of struct.Struct()#145580

Open
serhiy-storchaka wants to merge 29 commits intopython:mainfrom
serhiy-storchaka:deprecate-struct-init
Open

gh-143715: Deprecate incomplete initialization of struct.Struct()#145580
serhiy-storchaka wants to merge 29 commits intopython:mainfrom
serhiy-storchaka:deprecate-struct-init

Conversation

@serhiy-storchaka
Copy link
Member

@serhiy-storchakaserhiy-storchaka commentedMar 6, 2026
edited by github-actionsbot
Loading

  • Struct.__new__() will require a mandatory argument (format)
  • Calls of__init__() method on initialized Struct are deprecated

This is an evolution of#143659, but since virtually all code and test were rewritten I created a new PR.


📚 Documentation preview 📚:https://cpython-previews--145580.org.readthedocs.build/

skirpichevand others added29 commitsJanuary 10, 2026 16:37
* ``Struct.__new__()`` will require a mandatory argument (format)* Calls of ``__init__()`` method on initialized Struct are deprecated
This make format argument in the __init__() - optional.  If it'smissing, the object must be already initialized in __new__().
Co-authored-by: Victor Stinner <vstinner@python.org>
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
This catch current pattern for Struct's subclassing likeclass MyStruct(Struct):    def __init__(self):        super().__init__('>h')
:meth:`~object.__init__` method on initialized:class:`~struct.Struct`
objects is deprecated and will be removed in Python 3.20.

(Contributed by Sergey B Kirpichev in:gh:`143715`.)
Copy link
Member

Choose a reason for hiding this comment

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

Suggested change
(Contributed bySergey B Kirpichev in:gh:`143715`.)
(Contributed bySerhiy Storchaka in:gh:`143715`.)

:meth:`~object.__init__` method on initialized :class:`~struct.Struct`
objects is deprecated and will be removed in Python 3.20.

(Contributed by Sergey B Kirpichev in :gh:`143715`.)
Copy link
Member

Choose a reason for hiding this comment

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

Suggested change
(Contributed bySergey B Kirpichev in:gh:`143715`.)
(Contributed bySerhiy Storchaka in:gh:`143715`.)

def check_sizeof(self, format_str, number_of_codes):
# The size of 'PyStructObject'
totalsize = support.calcobjsize('2n3P')
totalsize = support.calcobjsize('2n3P1?')
Copy link
Member

Choose a reason for hiding this comment

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

Suggested change
totalsize=support.calcobjsize('2n3P1?')
totalsize=support.calcobjsize('2n3P?')

super().__init__('>h')

my_struct = MyStruct('>h')
self.assertEqual(my_struct.pack(12345), b'\x30\x39')
Copy link
Member

Choose a reason for hiding this comment

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

I think this will be more clear, per Victor's suggestion:

Suggested change
self.assertEqual(my_struct.pack(12345),b'\x30\x39')
self.assertEqual(my_struct.format,'>h')

(and in all cases below too)

def __init__(self, *args, **kwargs):
super().__init__('>h')

my_struct = MyStruct('>h')
Copy link
Member

Choose a reason for hiding this comment

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

Why this not raises a warning? I think we should warn in all cases, whereStruct.__init__() was explicitly called. //#143659 (comment)


my_struct = MyStruct('>h')
self.assertEqual(my_struct.pack(12345), b'\x30\x39')
my_struct = MyStruct(format='>h')
Copy link
Member

Choose a reason for hiding this comment

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

Ah, I entirely forgot thatformat is a positional or keyword argument in the master. I'll fix my patch.

But again, this should emit a warning.

Comment on lines +880 to +888
# New way, no warnings:
class MyStruct(struct.Struct):
def __new__(cls, newargs, initargs):
return super().__new__(cls, *newargs)
def __init__(self, newargs, initargs):
if initargs is not None:
super().__init__(*initargs)

my_struct = MyStruct(('>h',), ('>h',))
Copy link
Member

Choose a reason for hiding this comment

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

Again, why no warnings here?

BTW, I doubt this usage pattern come from reality ;-)

Sign up for freeto join this conversation on GitHub. Already have an account?Sign in to comment

Reviewers

@skirpichevskirpichevskirpichev left review comments

@vstinnervstinnerAwaiting requested review from vstinner

@AA-TurnerAA-TurnerAwaiting requested review from AA-TurnerAA-Turner is a code owner

Assignees

No one assigned

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

2 participants

@serhiy-storchaka@skirpichev

[8]ページ先頭

©2009-2026 Movatter.jp