Drop Python 3.7 (#1340)

* Drop Python 3.7

* Add news fragment

* update Ruff

.github/workflows/ci.yml

@@ -63,7 +63,7 @@ jobs:
           V=${{ matrix.python-version }}
           DO_MYPY=1
 
-          if [[ "$V" == "3.7" || "$V" == "3.8" ]]; then
+          if [[ "$V" == "3.8" ]]; then
             DO_MYPY=0
           fi
 
@@ -73,7 +73,6 @@ jobs:
           uv pip install --system tox
 
       - run: uv pip install --system tox-uv
-        if: matrix.python-version != '3.7'
 
       - run: python -Im tox run -e ${{ env.TOX_PYTHON }}-mypy
         if: env.DO_MYPY == '1'

.pre-commit-config.yaml

@@ -9,7 +9,7 @@ repos:
       - id: black
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.6.2
+    rev: v0.6.3
     hooks:
       - id: ruff
         args: [--fix, --exit-non-zero-on-fix]

changelog.d/1340.breaking.md

@@ -0,0 +1 @@
+Python 3.7 has been dropped.

pyproject.toml

@@ -9,13 +9,12 @@ build-backend = "hatchling.build"
 name = "attrs"
 authors = [{ name = "Hynek Schlawack", email = "hs@ox.cx" }]
 license = { text = "MIT" }
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 description = "Classes Without Boilerplate"
 keywords = ["class", "attribute", "boilerplate"]
 classifiers = [
   "Development Status :: 5 - Production/Stable",
   "License :: OSI Approved :: MIT License",
-  "Programming Language :: Python :: 3.7",
   "Programming Language :: Python :: 3.8",
   "Programming Language :: Python :: 3.9",
   "Programming Language :: Python :: 3.10",
@@ -26,7 +25,7 @@ classifiers = [
   "Programming Language :: Python :: Implementation :: PyPy",
   "Typing :: Typed",
 ]
-dependencies = ["importlib_metadata;python_version<'3.8'"]
+dependencies = []
 dynamic = ["version", "readme"]
 
 [project.optional-dependencies]

src/attr/__init__.py

@@ -5,11 +5,10 @@ Classes Without Boilerplate
 """
 
 from functools import partial
-from typing import Callable
+from typing import Callable, Protocol
 
 from . import converters, exceptions, filters, setters, validators
 from ._cmp import cmp_using
-from ._compat import Protocol
 from ._config import get_run_validators, set_run_validators
 from ._funcs import asdict, assoc, astuple, evolve, has, resolve_types
 from ._make import (
@@ -85,10 +84,7 @@ def _make_getattr(mod_name: str) -> Callable:
             msg = f"module {mod_name} has no attribute {name}"
             raise AttributeError(msg)
 
-        try:
+        from importlib.metadata import metadata
-            from importlib.metadata import metadata
-        except ImportError:
-            from importlib_metadata import metadata
 
         meta = metadata("attrs")
 

src/attr/__init__.pyi

@@ -76,29 +76,20 @@ NOTHING = _Nothing.NOTHING
 # NOTE: Factory lies about its return type to make this possible:
 # `x: List[int] # = Factory(list)`
 # Work around mypy issue #4554 in the common case by using an overload.
-if sys.version_info >= (3, 8):
+from typing import Literal
-    from typing import Literal
-    @overload
-    def Factory(factory: Callable[[], _T]) -> _T: ...
-    @overload
-    def Factory(
-        factory: Callable[[Any], _T],
-        takes_self: Literal[True],
-    ) -> _T: ...
-    @overload
-    def Factory(
-        factory: Callable[[], _T],
-        takes_self: Literal[False],
-    ) -> _T: ...
 
-else:
+@overload
-    @overload
+def Factory(factory: Callable[[], _T]) -> _T: ...
-    def Factory(factory: Callable[[], _T]) -> _T: ...
+@overload
-    @overload
+def Factory(
-    def Factory(
+    factory: Callable[[Any], _T],
-        factory: Union[Callable[[Any], _T], Callable[[], _T]],
+    takes_self: Literal[True],
-        takes_self: bool = ...,
+) -> _T: ...
-    ) -> _T: ...
+@overload
+def Factory(
+    factory: Callable[[], _T],
+    takes_self: Literal[False],
+) -> _T: ...
 
 In = TypeVar("In")
 Out = TypeVar("Out")

src/attr/_compat.py

@@ -10,7 +10,6 @@ from typing import _GenericAlias
 
 
 PYPY = platform.python_implementation() == "PyPy"
-PY_3_8_PLUS = sys.version_info[:2] >= (3, 8)
 PY_3_9_PLUS = sys.version_info[:2] >= (3, 9)
 PY_3_10_PLUS = sys.version_info[:2] >= (3, 10)
 PY_3_11_PLUS = sys.version_info[:2] >= (3, 11)
@@ -19,14 +18,6 @@ PY_3_13_PLUS = sys.version_info[:2] >= (3, 13)
 PY_3_14_PLUS = sys.version_info[:2] >= (3, 14)
 
 
-if sys.version_info < (3, 8):
-    try:
-        from typing_extensions import Protocol
-    except ImportError:  # pragma: no cover
-        Protocol = object
-else:
-    from typing import Protocol  # noqa: F401
-
 if PY_3_14_PLUS:  # pragma: no cover
     import annotationlib
 

src/attr/_make.py

@@ -20,7 +20,6 @@ from operator import itemgetter
 # having the thread-local in the globals here.
 from . import _compat, _config, setters
 from ._compat import (
-    PY_3_8_PLUS,
     PY_3_10_PLUS,
     PY_3_11_PLUS,
     _AnnotationExtractor,
@@ -790,16 +789,11 @@ class _ClassBuilder:
         ):
             names += ("__weakref__",)
 
-        if PY_3_8_PLUS:
+        cached_properties = {
-            cached_properties = {
+            name: cached_property.func
-                name: cached_property.func
+            for name, cached_property in cd.items()
-                for name, cached_property in cd.items()
+            if isinstance(cached_property, functools.cached_property)
-                if isinstance(cached_property, functools.cached_property)
+        }
-            }
-        else:
-            # `functools.cached_property` was introduced in 3.8.
-            # So can't be used before this.
-            cached_properties = {}
 
         # Collect methods with a `__class__` reference that are shadowed in the new class.
         # To know to update them.
@@ -2213,7 +2207,7 @@ def _attrs_to_init_script(
         # If pre init method has arguments, pass same arguments as `__init__`.
         lines[0] = f"self.__attrs_pre_init__({pre_init_args})"
 
-    # Python 3.7 doesn't allow backslashes in f strings.
+    # Python <3.12 doesn't allow backslashes in f-strings.
     NL = "\n    "
     return (
         f"""def {method_name}(self, {args}):

tests/strategies.py

@@ -13,8 +13,6 @@ from hypothesis import strategies as st
 
 import attr
 
-from attr._compat import PY_3_8_PLUS
-
 from .utils import make_class
 
 
@@ -189,9 +187,7 @@ def simple_classes(
         cls_dict["__init__"] = init
 
     bases = (object,)
-    if cached_property or (
+    if cached_property or (cached_property is None and cached_property_flag):
-        PY_3_8_PLUS and cached_property is None and cached_property_flag
-    ):
 
         class BaseWithCachedProperty:
             @functools.cached_property

tests/test_compat.py

@@ -2,6 +2,8 @@
 
 import types
 
+from typing import Protocol
+
 import pytest
 
 import attr
@@ -59,5 +61,5 @@ def test_attrsinstance_subclass_protocol():
     It's possible to subclass AttrsInstance and Protocol at once.
     """
 
-    class Foo(attr.AttrsInstance, attr._compat.Protocol):
+    class Foo(attr.AttrsInstance, Protocol):
         def attribute(self) -> int: ...

tests/test_make.py

@@ -21,7 +21,7 @@ from hypothesis.strategies import booleans, integers, lists, sampled_from, text
 import attr
 
 from attr import _config
-from attr._compat import PY_3_8_PLUS, PY_3_10_PLUS, PY_3_14_PLUS
+from attr._compat import PY_3_10_PLUS, PY_3_14_PLUS
 from attr._make import (
     Attribute,
     Factory,
@@ -1837,7 +1837,6 @@ class TestClassBuilder:
 
         assert [C2] == C.__subclasses__()
 
-    @pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
     @pytest.mark.xfail(PY_3_14_PLUS, reason="Currently broken on nightly.")
     def test_no_references_to_original_when_using_cached_property(self):
         """

tests/test_packaging.py

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: MIT
 
-import sys
+
+from importlib import metadata
 
 import pytest
 
@@ -8,12 +9,6 @@ import attr
 import attrs
 
 
-if sys.version_info < (3, 8):
-    import importlib_metadata as metadata
-else:
-    from importlib import metadata
-
-
 @pytest.fixture(name="mod", params=(attr, attrs))
 def _mod(request):
     return request.param

tests/test_slots.py

@@ -15,7 +15,7 @@ import pytest
 import attr
 import attrs
 
-from attr._compat import PY_3_8_PLUS, PY_3_14_PLUS, PYPY
+from attr._compat import PY_3_14_PLUS, PYPY
 
 
 # Pympler doesn't work on PyPy.
@@ -722,7 +722,6 @@ def test_slots_super_property_get_shortcut():
     assert B(17).f == 289
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_property_allows_call():
     """
     cached_property in slotted class allows call.
@@ -739,7 +738,6 @@ def test_slots_cached_property_allows_call():
     assert A(11).f == 11
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_property_class_does_not_have__dict__():
     """
     slotted class with cached property has no __dict__ attribute.
@@ -757,7 +755,6 @@ def test_slots_cached_property_class_does_not_have__dict__():
     assert "__dict__" not in dir(A)
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_property_works_on_frozen_isntances():
     """
     Infers type of cached property.
@@ -774,7 +771,6 @@ def test_slots_cached_property_works_on_frozen_isntances():
     assert A(x=1).f == 1
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 @pytest.mark.xfail(
     PY_3_14_PLUS, reason="3.14 returns weird annotation for cached_properies"
 )
@@ -794,7 +790,6 @@ def test_slots_cached_property_infers_type():
     assert A.__annotations__ == {"x": int, "f": int}
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_property_with_empty_getattr_raises_attribute_error_of_requested():
     """
     Ensures error information is not lost.
@@ -815,7 +810,6 @@ def test_slots_cached_property_with_empty_getattr_raises_attribute_error_of_requ
         a.z
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_property_raising_attributeerror():
     """
     Ensures AttributeError raised by a property is preserved by __getattr__()
@@ -854,7 +848,6 @@ def test_slots_cached_property_raising_attributeerror():
     assert a.q == 2
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_property_with_getattr_calls_getattr_for_missing_attributes():
     """
     Ensure __getattr__ implementation is maintained for non cached_properties.
@@ -876,7 +869,6 @@ def test_slots_cached_property_with_getattr_calls_getattr_for_missing_attributes
     assert a.z == "z"
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_getattr_in_superclass__is_called_for_missing_attributes_when_cached_property_present():
     """
     Ensure __getattr__ implementation is maintained in subclass.
@@ -900,7 +892,6 @@ def test_slots_getattr_in_superclass__is_called_for_missing_attributes_when_cach
     assert b.z == "z"
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_getattr_in_subclass_gets_superclass_cached_property():
     """
     Ensure super() in __getattr__ is not broken through cached_property re-write.
@@ -931,7 +922,6 @@ def test_slots_getattr_in_subclass_gets_superclass_cached_property():
     assert b.z == "z"
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_sub_class_with_independent_cached_properties_both_work():
     """
     Subclassing shouldn't break cached properties.
@@ -955,7 +945,6 @@ def test_slots_sub_class_with_independent_cached_properties_both_work():
     assert B(1).g == 2
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_with_multiple_cached_property_subclasses_works():
     """
     Multiple sub-classes shouldn't break cached properties.
@@ -991,7 +980,6 @@ def test_slots_with_multiple_cached_property_subclasses_works():
     assert ab.h == "h"
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slotted_cached_property_can_access_super():
     """
     Multiple sub-classes shouldn't break cached properties.
@@ -1010,7 +998,6 @@ def test_slotted_cached_property_can_access_super():
     assert B(x=1).f == 2
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_sub_class_avoids_duplicated_slots():
     """
     Duplicating the slots is a waste of memory.
@@ -1034,7 +1021,6 @@ def test_slots_sub_class_avoids_duplicated_slots():
     assert B.__slots__ == ()
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_sub_class_with_actual_slot():
     """
     A sub-class can have an explicit attrs field that replaces a cached property.
@@ -1056,7 +1042,6 @@ def test_slots_sub_class_with_actual_slot():
     assert B.__slots__ == ()
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_property_is_not_called_at_construction():
     """
     A cached property function should only be called at property access point.
@@ -1077,7 +1062,6 @@ def test_slots_cached_property_is_not_called_at_construction():
     assert call_count == 0
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_property_repeat_call_only_once():
     """
     A cached property function should be called only once, on repeated attribute access.
@@ -1100,7 +1084,6 @@ def test_slots_cached_property_repeat_call_only_once():
     assert call_count == 1
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_property_called_independent_across_instances():
     """
     A cached property value should be specific to the given instance.
@@ -1121,7 +1104,6 @@ def test_slots_cached_property_called_independent_across_instances():
     assert obj_2.f == 2
 
 
-@pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_properties_work_independently():
     """
     Multiple cached properties should work independently.

tox.ini

@@ -2,7 +2,7 @@
 min_version = 4
 env_list =
     pre-commit,
-    py3{7,8,9,10,11,12,13}-tests,
+    py3{8,9,10,11,12,13}-tests,
     py3{9,10,11,12,13}-mypy,
     pypy3,
     pyright,
@@ -26,7 +26,7 @@ commands =
     mypy: mypy tests/typing_example.py
     mypy: mypy src/attrs/__init__.pyi src/attr/__init__.pyi src/attr/_typing_compat.pyi src/attr/_version_info.pyi src/attr/converters.pyi src/attr/exceptions.pyi src/attr/filters.pyi src/attr/setters.pyi src/attr/validators.pyi
 
-[testenv:py3{7,10,12}-tests]
+[testenv:py3{8,10,12}-tests]
 extras = cov
 # Python 3.6+ has a number of compile-time warnings on invalid string escapes.
 # PYTHONWARNINGS=d makes them visible during the tox run.
@@ -41,7 +41,7 @@ commands = coverage run -m pytest {posargs:-n auto --dist loadfile}
 # Keep base_python in-sync with .python-version-default
 base_python = py312
 # Keep depends in-sync with testenv above that has cov extra.
-depends = py3{7,10,12}
+depends = py3{8,10,12}
 skip_install = true
 deps = coverage[toml]>=5.3
 commands =