Drop support for running with Python 3.8

.github/workflows/docs.yml

@@ -36,7 +36,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: '3.8'
+          python-version: '3.9'
       - name: Install tox
         run: pip install --upgrade 'setuptools!=50' tox==4.11.0
       - name: Setup tox environment

.github/workflows/test.yml

@@ -31,24 +31,18 @@ jobs:
         include:
         # Make sure to run mypyc compiled unit tests for both
         # the oldest and newest supported Python versions
-        - name: Test suite with py38-ubuntu, mypyc-compiled
-          python: '3.8'
+        - name: Test suite with py39-ubuntu, mypyc-compiled
+          python: '3.9'
           arch: x64
           os: ubuntu-latest
           toxenv: py
           tox_extra_args: "-n 4"
           test_mypyc: true
-        - name: Test suite with py38-windows-64
-          python: '3.8'
-          arch: x64
-          os: windows-latest
-          toxenv: py38
-          tox_extra_args: "-n 4"
-        - name: Test suite with py39-ubuntu
+        - name: Test suite with py39-windows-64
           python: '3.9'
           arch: x64
-          os: ubuntu-latest
-          toxenv: py
+          os: windows-latest
+          toxenv: py39
           tox_extra_args: "-n 4"
         - name: Test suite with py310-ubuntu
           python: '3.10'
@@ -72,27 +66,27 @@ jobs:
           test_mypyc: true
 
         - name: mypyc runtime tests with py39-macos
-          python: '3.9.18'
+          python: '3.9.19'
           arch: x64
           # TODO: macos-13 is the last one to support Python 3.9, change it to macos-latest when updating the Python version
           os: macos-13
           toxenv: py
           tox_extra_args: "-n 3 mypyc/test/test_run.py mypyc/test/test_external.py"
-        - name: mypyc runtime tests with py38-debug-build-ubuntu
-          python: '3.8.17'
+        - name: mypyc runtime tests with py39-debug-build-ubuntu
+          python: '3.9.19'
           arch: x64
           os: ubuntu-latest
           toxenv: py
           tox_extra_args: "-n 4 mypyc/test/test_run.py mypyc/test/test_external.py"
           debug_build: true
 
-        - name: Type check our own code (py38-ubuntu)
-          python: '3.8'
+        - name: Type check our own code (py39-ubuntu)
+          python: '3.9'
           arch: x64
           os: ubuntu-latest
           toxenv: type
-        - name: Type check our own code (py38-windows-64)
-          python: '3.8'
+        - name: Type check our own code (py39-windows-64)
+          python: '3.9'
           arch: x64
           os: windows-latest
           toxenv: type

.github/workflows/test_stubgenc.yml

@@ -29,10 +29,10 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - name: Setup 🐍 3.8
+    - name: Setup 🐍 3.9
       uses: actions/setup-python@v5
       with:
-        python-version: 3.8
+        python-version: 3.9
 
     - name: Test stubgenc
       run: misc/test-stubgenc.sh

CONTRIBUTING.md

@@ -51,7 +51,7 @@ hash -r  # This resets shell PATH cache, not necessary on Windows
 ```
 
 > **Note**
-> You'll need Python 3.8 or higher to install all requirements listed in
+> You'll need Python 3.9 or higher to install all requirements listed in
 > test-requirements.txt
 
 ### Running tests

mypy/defaults.py

@@ -6,7 +6,7 @@
 # Earliest fully supported Python 3.x version. Used as the default Python
 # version in tests. Mypy wheels should be built starting with this version,
 # and CI tests should be run on this version (and later versions).
-PYTHON3_VERSION: Final = (3, 8)
+PYTHON3_VERSION: Final = (3, 9)
 
 # Earliest Python 3.x version supported via --python-version 3.x. To run
 # mypy, at least version PYTHON3_VERSION is needed.

mypy/test/meta/test_parse_data.py

@@ -50,13 +50,13 @@ def test_bad_ge_version_check(self) -> None:
             """
             [case abc]
             s: str
-            [out version>=3.8]
+            [out version>=3.9]
             abc
             """
         )
 
         # Assert
-        assert "version>=3.8 always true since minimum runtime version is (3, 8)" in actual.stdout
+        assert "version>=3.9 always true since minimum runtime version is (3, 9)" in actual.stdout
 
     def test_bad_eq_version_check(self) -> None:
         # Act
@@ -70,4 +70,4 @@ def test_bad_eq_version_check(self) -> None:
         )
 
         # Assert
-        assert "version==3.7 always false since minimum runtime version is (3, 8)" in actual.stdout
+        assert "version==3.7 always false since minimum runtime version is (3, 9)" in actual.stdout

mypy/util.py

@@ -451,10 +451,10 @@ def get_unique_redefinition_name(name: str, existing: Container[str]) -> str:
 def check_python_version(program: str) -> None:
     """Report issues with the Python used to run mypy, dmypy, or stubgen"""
     # Check for known bad Python versions.
-    if sys.version_info[:2] < (3, 8):  # noqa: UP036
+    if sys.version_info[:2] < (3, 9):
         sys.exit(
-            "Running {name} with Python 3.7 or lower is not supported; "
-            "please upgrade to 3.8 or newer".format(name=program)
+            "Running {name} with Python 3.8 or lower is not supported; "
+            "please upgrade to 3.9 or newer".format(name=program)
         )
 
 

mypy_self_check.ini

@@ -6,7 +6,7 @@ show_traceback = True
 pretty = True
 always_false = MYPYC
 plugins = mypy.plugins.proper_plugin
-python_version = 3.8
+python_version = 3.9
 exclude = mypy/typeshed/|mypyc/test-data/|mypyc/lib-rt/
 enable_error_code = ignore-without-code,redundant-expr
 enable_incomplete_feature = PreciseTupleTypes

mypyc/doc/getting_started.rst

@@ -38,7 +38,7 @@ Installation
 ------------
 
 Mypyc is shipped as part of the mypy distribution. Install mypy like
-this (you need Python 3.8 or later):
+this (you need Python 3.9 or later):
 
 .. code-block::
 

setup.py

@@ -8,8 +8,8 @@
 import sys
 from typing import TYPE_CHECKING, Any
 
-if sys.version_info < (3, 8, 0):  # noqa: UP036
-    sys.stderr.write("ERROR: You need Python 3.8 or later to use mypy.\n")
+if sys.version_info < (3, 9, 0):
+    sys.stderr.write("ERROR: You need Python 3.9 or later to use mypy.\n")
     exit(1)
 
 # we'll import stuff from the source tree, let's ensure is on the sys path
@@ -185,7 +185,6 @@ def run(self):
     "Intended Audience :: Developers",
     "License :: OSI Approved :: MIT License",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
@@ -232,7 +231,7 @@ def run(self):
         "reports": "lxml",
         "install-types": "pip",
     },
-    python_requires=">=3.8",
+    python_requires=">=3.9",
     include_package_data=True,
     project_urls={
         "Documentation": "https://mypy.readthedocs.io/en/stable/index.html",

test-data/unit/check-columns.test

@@ -250,7 +250,7 @@ class D(A):
                               # N:5:          def f(self) -> None
 
 [case testColumnMissingTypeParameters]
-# flags: --disallow-any-generics
+# flags: --python-version 3.8 --disallow-any-generics
 from typing import List, Callable
 def f(x: List) -> None: pass # E:10: Missing type parameters for generic type "List"
 def g(x: list) -> None: pass # E:10: Implicit generic "Any". Use "typing.List" and specify generic parameters

test-data/unit/check-errorcodes.test

@@ -328,7 +328,7 @@ a: A
 a.x = ''  # E: Incompatible types in assignment (expression has type "str", variable has type "int")  [assignment]
 
 [case testErrorCodeMissingTypeArg]
-# flags: --disallow-any-generics
+# flags: --python-version 3.8 --disallow-any-generics
 from typing import List, TypeVar
 x: List  # E: Missing type parameters for generic type "List"  [type-arg]
 y: list  # E: Implicit generic "Any". Use "typing.List" and specify generic parameters  [type-arg]

test-data/unit/check-functools.test

@@ -287,6 +287,7 @@ p1("a", "b")  # TODO: false negative
 [builtins fixtures/dict.pyi]
 
 [case testFunctoolsPartialTypeGuard]
+# flags: --python-version 3.8
 import functools
 from typing_extensions import TypeGuard
 

test-data/unit/check-generics.test

@@ -515,6 +515,7 @@ Alias[int]("a")  # E: Argument 1 to "Node" has incompatible type "str"; expected
 [out]
 
 [case testTypeApplicationCrash]
+# flags: --python-version 3.8
 import types
 type[int] # this was crashing, see #2302 (comment)  # E: The type "Type[type]" is not generic and not indexable
 [builtins fixtures/tuple.pyi]
@@ -1130,6 +1131,7 @@ reveal_type(Bad) # N: Revealed type is "Any"
 [out]
 
 [case testNoSubscriptionOfBuiltinAliases]
+# flags: --python-version 3.8
 from typing import List, TypeVar
 
 list[int]() # E: "list" is not subscriptable

test-data/unit/check-incremental.test

@@ -3753,7 +3753,7 @@ import b
 [file b.py]
 -- This is a heinous hack, but we simulate having a invalid cache by clobbering
 -- the proto deps file with something with mtime mismatches.
-[file ../.mypy_cache/3.8/@deps.meta.json.2]
+[file ../.mypy_cache/3.9/@deps.meta.json.2]
 {"snapshot": {"__main__": "a7c958b001a45bd6a2a320f4e53c4c16", "a": "d41d8cd98f00b204e9800998ecf8427e", "b": "d41d8cd98f00b204e9800998ecf8427e", "builtins": "c532c89da517a4b779bcf7a964478d67"}, "deps_meta": {"@root": {"path": "@root.deps.json", "mtime": 0}, "__main__": {"path": "__main__.deps.json", "mtime": 0}, "a": {"path": "a.deps.json", "mtime": 0}, "b": {"path": "b.deps.json", "mtime": 0}, "builtins": {"path": "builtins.deps.json", "mtime": 0}}}
 [file ../.mypy_cache/.gitignore]
 # Another hack to not trigger a .gitignore creation failure "false positive"
@@ -3788,7 +3788,7 @@ import b
 [file b.py]
 -- This is a heinous hack, but we simulate having a invalid cache by deleting
 -- the proto deps file.
-[delete ../.mypy_cache/3.8/@deps.meta.json.2]
+[delete ../.mypy_cache/3.9/@deps.meta.json.2]
 [file b.py.2]
 # uh
 -- Every file should get reloaded, since the cache was invalidated

test-data/unit/fine-grained-cache-incremental.test

@@ -202,7 +202,7 @@ a.py:8: note:     x: expected "int", got "str"
 [file b.py]
 -- This is a heinous hack, but we simulate having a invalid cache by clobbering
 -- the proto deps file with something with mtime mismatches.
-[file ../.mypy_cache/3.8/@deps.meta.json.2]
+[file ../.mypy_cache/3.9/@deps.meta.json.2]
 {"snapshot": {"__main__": "a7c958b001a45bd6a2a320f4e53c4c16", "a": "d41d8cd98f00b204e9800998ecf8427e", "b": "d41d8cd98f00b204e9800998ecf8427e", "builtins": "c532c89da517a4b779bcf7a964478d67"}, "deps_meta": {"@root": {"path": "@root.deps.json", "mtime": 0}, "__main__": {"path": "__main__.deps.json", "mtime": 0}, "a": {"path": "a.deps.json", "mtime": 0}, "b": {"path": "b.deps.json", "mtime": 0}, "builtins": {"path": "builtins.deps.json", "mtime": 0}}}
 
 [file b.py.2]
@@ -234,8 +234,8 @@ x = 10
 [file p/c.py]
 class C: pass
 
-[delete ../.mypy_cache/3.8/b.meta.json.2]
-[delete ../.mypy_cache/3.8/p/c.meta.json.2]
+[delete ../.mypy_cache/3.9/b.meta.json.2]
+[delete ../.mypy_cache/3.9/p/c.meta.json.2]
 
 [out]
 ==

test-data/unit/fine-grained.test

@@ -10192,7 +10192,7 @@ class Base(Protocol):
 main:5: error: Call to abstract method "meth" of "Base" with trivial body via super() is unsafe
 
 [case testPrettyMessageSorting]
-# flags: --pretty
+# flags: --python-version 3.8 --pretty
 import a
 
 [file a.py]

test-requirements.in

@@ -16,4 +16,4 @@ pytest-xdist>=1.34.0
 pytest-cov>=2.10.0
 ruff==0.2.0  # must match version in .pre-commit-config.yaml
 setuptools>=65.5.1
-tomli>=1.1.0  # needed even on py311+ so the self check passes with --python-version 3.8
+tomli>=1.1.0  # needed even on py311+ so the self check passes with --python-version 3.9