Skip to content

gh-89529: disallow default_factory for fields in dataclasses without __init__ #123070

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

Draft
wants to merge 5 commits into
base: main
Choose a base branch
from
+82 −0
Draft

gh-89529: disallow default_factory for fields in dataclasses without __init__ #123070

Changes from 1 commit
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
9c8ffe0
disallow `default_factory` for dataclasses without `__init__`
picnixz Aug 16, 2024
204ec65
blurb
picnixz Aug 16, 2024
c55ec4e
add test case with `init=True` and user-defined `__init__`
picnixz Aug 17, 2024
72adf72
Merge branch 'main' into 89529-dataclasses-default-factory-and-init
picnixz Oct 24, 2024
d3abe77
Merge branch 'main' into 89529-dataclasses-default-factory-and-init
picnixz Nov 15, 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
Prev Previous commit
Next Next commit
add test case with init=True and user-defined __init__
  • Loading branch information
@picnixz
picnixz committed Aug 17, 2024
commit c55ec4e4bc03f6f987e5b7c6c8bfd4fcefc1d3cc
16 changes: 13 additions & 3 deletions Lib/test/test_dataclasses/__init__.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1413,7 +1413,7 @@ class C:
C().x
self.assertEqual(factory.call_count, 2)

def test_default_factory_with_no_init_method(self):
def test_default_factory_and_init_method_interaction(self):
# See https://github.com/python/cpython/issues/89529.

@dataclass
Expand Down Expand Up @@ -1452,8 +1452,8 @@ class C(base_class):
self.assertListEqual(C().x, [])

with self.subTest('user-defined __init__', base_class=base_class,
init=False, slots=slots, field_init=field_init):
@dataclass(init=False, slots=slots)
init=True, slots=slots, field_init=field_init):
@dataclass(init=True, slots=slots)
class C(base_class):
x: list = field(init=field_init, default_factory=list)
def __init__(self, *a, **kw):
Expand All @@ -1468,6 +1468,16 @@ def __init__(self, *a, **kw):
class C(base_class):
x: list = field(init=field_init, default_factory=list)

with self.subTest('user-defined __init__', base_class=base_class,
init=False, slots=slots, field_init=field_init):
@dataclass(init=False, slots=slots)
class C(base_class):
x: list = field(init=field_init, default_factory=list)
def __init__(self, *a, **kw):
# deliberately use something else
self.x = 'world'
self.assertEqual(C().x, 'world')

def test_default_factory_not_called_if_value_given(self):
# We need a factory that we can test if it's been called.
factory = Mock()
Expand Down
Loading