No longer support checking Python 2 (#13135)

Linking #12237

Author: hauntsaninja

mypy/main.py

@@ -955,6 +955,11 @@ def set_strict_flags() -> None:
     # The python_version is either the default, which can be overridden via a config file,
     # or stored in special_opts and is passed via the command line.
     options.python_version = special_opts.python_version or options.python_version
+    if options.python_version < (3,):
+        parser.error(
+            "Mypy no longer supports checking Python 2 code. "
+            "Consider pinning to mypy<0.980 if you need to check Python 2 code."
+        )
     try:
         infer_python_executable(options, special_opts)
     except PythonExecutableInferenceError as e:

mypy/test/helpers.py

@@ -286,16 +286,15 @@ def num_skipped_suffix_lines(a1: List[str], a2: List[str]) -> int:
 
 
 def testfile_pyversion(path: str) -> Tuple[int, int]:
-    if path.endswith('python2.test'):
-        return defaults.PYTHON2_VERSION
-    elif path.endswith('python310.test'):
+    if path.endswith('python310.test'):
         return 3, 10
     else:
         return defaults.PYTHON3_VERSION
 
 
 def testcase_pyversion(path: str, testcase_name: str) -> Tuple[int, int]:
     if testcase_name.endswith('python2'):
+        raise ValueError(testcase_name)
         return defaults.PYTHON2_VERSION
     else:
         return testfile_pyversion(path)

mypy/test/testdeps.py

@@ -6,7 +6,7 @@
 from typing import List, Tuple, Dict, Optional, Set
 from typing_extensions import DefaultDict
 
-from mypy import build, defaults
+from mypy import build
 from mypy.modulefinder import BuildSource
 from mypy.errors import CompileError
 from mypy.nodes import MypyFile, Expression
@@ -29,8 +29,6 @@ def run_case(self, testcase: DataDrivenTestCase) -> None:
         src = '\n'.join(testcase.input)
         dump_all = '# __dump_all__' in src
         options = parse_options(src, testcase, incremental_step=1)
-        if testcase.name.endswith('python2'):
-            options.python_version = defaults.PYTHON2_VERSION
         options.use_builtins_fixtures = True
         options.show_traceback = True
         options.cache_dir = os.devnull

mypy/test/testparse.py

@@ -31,9 +31,7 @@ def test_parser(testcase: DataDrivenTestCase) -> None:
     """
     options = Options()
 
-    if testcase.file.endswith('python2.test'):
-        options.python_version = defaults.PYTHON2_VERSION
-    elif testcase.file.endswith('python310.test'):
+    if testcase.file.endswith('python310.test'):
         options.python_version = (3, 10)
     else:
         options.python_version = defaults.PYTHON3_VERSION

mypy/test/testpythoneval.py

@@ -18,15 +18,12 @@
 import sys
 from tempfile import TemporaryDirectory
 
-import pytest
-
 from typing import List
 
 from mypy.defaults import PYTHON3_VERSION
 from mypy.test.config import test_temp_dir
 from mypy.test.data import DataDrivenTestCase, DataSuite
 from mypy.test.helpers import assert_string_arrays_equal, split_lines
-from mypy.util import try_find_python2_interpreter
 from mypy import api
 
 # Path to Python 3 interpreter
@@ -36,7 +33,6 @@
 
 class PythonEvaluationSuite(DataSuite):
     files = ['pythoneval.test',
-             'python2eval.test',
              'pythoneval-asyncio.test']
     cache_dir = TemporaryDirectory()
 
@@ -59,18 +55,8 @@ def test_python_evaluation(testcase: DataDrivenTestCase, cache_dir: str) -> None
         '--no-silence-site-packages',
         '--no-error-summary',
     ]
-    py2 = testcase.name.lower().endswith('python2')
-    if py2:
-        mypy_cmdline.append('--py2')
-        interpreter = try_find_python2_interpreter()
-        if interpreter is None:
-            # Skip, can't find a Python 2 interpreter.
-            pytest.skip()
-            # placate the type checker
-            return
-    else:
-        interpreter = python3_path
-        mypy_cmdline.append(f"--python-version={'.'.join(map(str, PYTHON3_VERSION))}")
+    interpreter = python3_path
+    mypy_cmdline.append(f"--python-version={'.'.join(map(str, PYTHON3_VERSION))}")
 
     m = re.search('# flags: (.*)$', '\n'.join(testcase.input), re.MULTILINE)
     if m:

mypy/test/testtransform.py

@@ -22,8 +22,7 @@ class TransformSuite(DataSuite):
              'semanal-types.test',
              'semanal-modules.test',
              'semanal-statements.test',
-             'semanal-abstractclasses.test',
-             'semanal-python2.test']
+             'semanal-abstractclasses.test']
     native_sep = True
 
     def run_case(self, testcase: DataDrivenTestCase) -> None:

test-data/unit/check-async-await.test

@@ -362,11 +362,6 @@ async def g():
 main:3: error: "yield from" in async function
 main:5: error: "yield from" in async function
 
-[case testNoAsyncDefInPY2_python2]
-
-async def f():  # E: invalid syntax
-    pass
-
 [case testYieldFromNoAwaitable]
 
 from typing import Any, Generator

test-data/unit/check-attr.test

@@ -35,7 +35,7 @@ A(1, 2, 3, 4)  # E: Argument 2 to "A" has incompatible type "int"; expected "Lis
 A(1, [2], '3', 4, 5)  # E: Too many arguments for "A"
 [builtins fixtures/list.pyi]
 
-[case testAttrsPython2Annotations]
+[case testAttrsTypeComments]
 import attr
 from typing import List, ClassVar
 @attr.s
@@ -1032,28 +1032,6 @@ class C:
 reveal_type(C)  # N: Revealed type is "def (a: builtins.int, b: builtins.int) -> __main__.C"
 [builtins fixtures/bool.pyi]
 
-[case testAttrsNewStyleClassPy2]
-# flags: --py2
-import attr
-@attr.s
-class Good(object):
-    pass
-@attr.s
-class Bad:  # E: attrs only works with new-style classes
-    pass
-@attr.s
-class SubclassOfBad(Bad):
-    pass
-[builtins_py2 fixtures/bool.pyi]
-
-[case testAttrsAutoAttribsPy2]
-# flags: --py2
-import attr
-@attr.s(auto_attribs=True)  # E: auto_attribs is not supported in Python 2
-class A(object):
-    x = attr.ib()
-[builtins_py2 fixtures/bool.pyi]
-
 [case testAttrsFrozenSubclass]
 import attr
 
@@ -1291,17 +1269,6 @@ class C:
 
 [builtins fixtures/attr.pyi]
 
-[case testAttrsKwOnlyPy2]
-# flags: --py2
-import attr
-@attr.s(kw_only=True)  # E: kw_only is not supported in Python 2
-class A(object):
-    x = attr.ib()
-@attr.s
-class B(object):
-    x = attr.ib(kw_only=True)  # E: kw_only is not supported in Python 2
-[builtins_py2 fixtures/bool.pyi]
-
 [case testAttrsDisallowUntypedWorksForward]
 # flags: --disallow-untyped-defs
 import attr

test-data/unit/check-classes.test

@@ -2207,7 +2207,7 @@ reveal_type(Num3() + Num1())  # N: Revealed type is "__main__.Num3"
 reveal_type(Num2() + Num3())  # N: Revealed type is "__main__.Num2"
 reveal_type(Num3() + Num2())  # N: Revealed type is "__main__.Num3"
 
-[case testDivReverseOperatorPython3]
+[case testDivReverseOperator]
 # No error: __div__ has no special meaning in Python 3
 class A1:
     def __div__(self, x: B1) -> int: ...
@@ -2222,37 +2222,6 @@ class B2:
 A1() / B1()                 # E: Unsupported left operand type for / ("A1")
 reveal_type(A2() / B2())    # N: Revealed type is "builtins.int"
 
-[case testDivReverseOperatorPython2]
-# flags: --python-version 2.7
-
-# Note: if 'from __future__ import division' is called, we use
-# __truediv__. Otherwise, we use __div__. So, we check both:
-class A1:
-    def __div__(self, x):
-        # type: (B1) -> int
-        pass
-class B1:
-    def __rdiv__(self, x):   # E: Signatures of "__rdiv__" of "B1" and "__div__" of "A1" are unsafely overlapping
-        # type: (A1) -> str
-        pass
-
-class A2:
-    def __truediv__(self, x):
-        # type: (B2) -> int
-        pass
-class B2:
-    def __rtruediv__(self, x):  # E: Signatures of "__rtruediv__" of "B2" and "__truediv__" of "A2" are unsafely overlapping
-        # type: (A2) -> str
-        pass
-
-# That said, mypy currently doesn't handle the actual division operation very
-# gracefully -- it doesn't correctly switch to using __truediv__ when
-# 'from __future__ import division' is included, it doesn't display a very
-# graceful error if __div__ is missing but __truediv__ is present...
-# Also see https://github.com/python/mypy/issues/2048
-reveal_type(A1() / B1())        # N: Revealed type is "builtins.int"
-A2() / B2()                     # E: "A2" has no attribute "__div__"
-
 [case testReverseOperatorMethodForwardIsAny]
 from typing import Any
 def deco(f: Any) -> Any: return f
@@ -2502,17 +2471,7 @@ reveal_type(B() + y)  # N: Revealed type is "Union[__main__.Out2, __main__.Out4]
 reveal_type(x + C())  # N: Revealed type is "Union[__main__.Out3, __main__.Out2]"
 reveal_type(x + D())  # N: Revealed type is "Union[__main__.Out1, __main__.Out4]"
 
-[case testOperatorDoubleUnionDivisionPython2]
-# flags: --python-version 2.7
-from typing import Union
-def f(a):
-    # type: (Union[int, float]) -> None
-    a /= 1.1
-    b = a / 1.1
-    reveal_type(b)  # N: Revealed type is "builtins.float"
-[builtins_py2 fixtures/ops.pyi]
-
-[case testOperatorDoubleUnionDivisionPython3]
+[case testOperatorDoubleUnionDivision]
 from typing import Union
 def f(a):
     # type: (Union[int, float]) -> None
@@ -5084,16 +5043,6 @@ reveal_type(type(A).x)  # N: Revealed type is "builtins.int"
 reveal_type(type(B).x)  # N: Revealed type is "builtins.int"
 [builtins fixtures/tuple.pyi]
 
-[case testSixMetaclass_python2]
-import six
-class M(type):
-    x = 5
-class A(six.with_metaclass(M)): pass
-@six.add_metaclass(M)
-class B: pass
-reveal_type(type(A).x)  # N: Revealed type is "builtins.int"
-reveal_type(type(B).x)  # N: Revealed type is "builtins.int"
-
 [case testFromSixMetaclass]
 from six import with_metaclass, add_metaclass
 class M(type):
@@ -5217,13 +5166,6 @@ class CQA(Q1): pass  # E: Inconsistent metaclass structure for "CQA"
 class CQW(six.with_metaclass(M, Q1)): pass  # E: Inconsistent metaclass structure for "CQW"
 [builtins fixtures/tuple.pyi]
 
-[case testSixMetaclassErrors_python2]
-# flags: --python-version 2.7
-import six
-class M(type): pass
-class C4(six.with_metaclass(M)):  # E: Multiple metaclass definitions
-    __metaclass__ = M
-
 [case testSixMetaclassAny]
 import t  # type: ignore
 import six
@@ -5244,13 +5186,6 @@ class A(future.utils.with_metaclass(M)): pass
 reveal_type(type(A).x)  # N: Revealed type is "builtins.int"
 [builtins fixtures/tuple.pyi]
 
-[case testFutureMetaclass_python2]
-import future.utils
-class M(type):
-    x = 5
-class A(future.utils.with_metaclass(M)): pass
-reveal_type(type(A).x)  # N: Revealed type is "builtins.int"
-
 [case testFromFutureMetaclass]
 from future.utils import with_metaclass
 class M(type):
@@ -5336,13 +5271,6 @@ class Q1(metaclass=M1): pass
 class CQW(future.utils.with_metaclass(M, Q1)): pass  # E: Inconsistent metaclass structure for "CQW"
 [builtins fixtures/tuple.pyi]
 
-[case testFutureMetaclassErrors_python2]
-# flags: --python-version 2.7
-import future.utils
-class M(type): pass
-class C4(future.utils.with_metaclass(M)):  # E: Multiple metaclass definitions
-    __metaclass__ = M
-
 [case testFutureMetaclassAny]
 import t  # type: ignore
 import future.utils
@@ -7323,7 +7251,7 @@ def foo(self: Any) -> str:
 from typing import Any, Callable, TypeVar
 
 class Parent:
-    foo = Callable[..., int] 
+    foo = Callable[..., int]
     class bar:
         pass
     import typing as baz

test-data/unit/check-columns.test

@@ -170,22 +170,6 @@ z: Iterable[bad] # E:13: Variable "__main__.bad" is not valid as a type \
 h: bad[int] # E:4: Variable "__main__.bad" is not valid as a type \
             # N:4: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
 
-[case testColumnInvalidType_python2]
-
-from typing import Iterable
-
-bad = 0
-
-if int():
-    def g(x): # E:5: Variable "__main__.bad" is not valid as a type \
-              # N:5: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
-        # type: (bad) -> None
-        y = 0  # type: bad  # E:9: Variable "__main__.bad" is not valid as a type \
-                            # N:9: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
-
-    z = ()  # type: Iterable[bad] # E:5: Variable "__main__.bad" is not valid as a type \
-                                  # N:5: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
-
 [case testColumnFunctionMissingTypeAnnotation]
 # flags: --disallow-untyped-defs
 if int():
@@ -216,14 +200,6 @@ def f(x, y): pass
 (f()) # E:2: Missing positional arguments "x", "y" in call to "f"
 (f(y=1)) # E:2: Missing positional argument "x" in call to "f"
 
-[case testColumnTooFewSuperArgs_python2]
-class A:
-    def f(self):
-        pass
-class B(A):
-    def f(self):   # type: () -> None
-        super().f()  # E:9: Too few arguments for "super"
-
 [case testColumnListOrDictItemHasIncompatibleType]
 from typing import List, Dict
 x: List[int] = [
@@ -316,12 +292,6 @@ if int():
         # type: (int) -> None
         pass
 
-[case testColumnTypeSignatureHasTooFewArguments_python2]
-if int():
-    def f(x, y): # E:5: Type signature has too few arguments
-        # type: (int) -> None
-        pass
-
 [case testColumnRevealedType]
 if int():
     reveal_type(1) # N:17: Revealed type is "Literal[1]?"
@@ -373,22 +343,6 @@ class B(A):
     def x(self) -> int: pass
 [builtins fixtures/property.pyi]
 
-[case testColumnProperty_python2]
-class A:
-    @property
-    def x(self): # type: () -> int
-        pass
-
-    @x.setter
-    def x(self, x): # type: (int) -> None
-        pass
-
-class B(A):
-    @property  # E:5: Read-only property cannot override read-write property
-    def x(self): # type: () -> int
-        pass
-[builtins_py2 fixtures/property_py2.pyi]
-
 [case testColumnOverloaded]
 from typing import overload, Any
 class A: