Drop 3.8 support

.github/workflows/autodeps.yml

@@ -24,13 +24,13 @@ jobs:
       - name: Setup python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.8"
+          python-version: "3.9"
 
       - name: Bump dependencies
         run: |
           python -m pip install -U pip pre-commit
           python -m pip install -r test-requirements.txt
-          uv pip compile --universal --python-version=3.8 --upgrade test-requirements.in -o test-requirements.txt
+          uv pip compile --universal --python-version=3.9 --upgrade test-requirements.in -o test-requirements.txt
           uv pip compile --universal --python-version=3.11 --upgrade docs-requirements.in -o docs-requirements.txt
           pre-commit autoupdate --jobs 0
 
@@ -43,7 +43,7 @@ jobs:
 
       - name: uv
         run: |
-          uv pip compile --universal --python-version=3.8 test-requirements.in -o test-requirements.txt
+          uv pip compile --universal --python-version=3.9 test-requirements.in -o test-requirements.txt
           uv pip compile --universal --python-version=3.11 docs-requirements.in -o docs-requirements.txt
 
       - name: Commit changes and create automerge PR

.github/workflows/ci.yml

@@ -18,23 +18,23 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['pypy-3.10', '3.8', '3.9', '3.10', '3.11', '3.12']
+        python: ['pypy-3.10', '3.9', '3.10', '3.11', '3.12', '3.13']
         arch: ['x86', 'x64']
         lsp: ['']
         lsp_extract_file: ['']
         extra_name: ['']
         include:
-          - python: '3.8'
+          - python: '3.9'
             arch: 'x64'
             lsp: 'https://raw.githubusercontent.com/python-trio/trio-ci-assets/master/komodia-based-vpn-setup.zip'
             lsp_extract_file: 'komodia-based-vpn-setup.exe'
             extra_name: ', with Komodia LSP'
-          - python: '3.8'
+          - python: '3.9'
             arch: 'x64'
             lsp: 'https://www.proxifier.com/download/legacy/ProxifierSetup342.exe'
             lsp_extract_file: ''
             extra_name: ', with IFS LSP'
-          #- python: '3.8'
+          #- python: '3.9'
           #  arch: 'x64'
           #  lsp: 'http://download.pctools.com/mirror/updates/9.0.0.2308-SDavfree-lite_en.exe'
           #  lsp_extract_file: ''
@@ -87,16 +87,16 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['pypy-3.10', '3.8', '3.9', '3.10', '3.11', '3.12', '3.13']
+        python: ['pypy-3.10', '3.9', '3.10', '3.11', '3.12', '3.13']
         check_formatting: ['0']
         no_test_requirements: ['0']
         extra_name: ['']
         include:
-          - python: '3.12'
+          - python: '3.13'
             check_formatting: '1'
             extra_name: ', check formatting'
           # separate test run that doesn't install test-requirements.txt
-          - python: '3.8'
+          - python: '3.9'
             no_test_requirements: '1'
             extra_name: ', no test-requirements'
     continue-on-error: >-
@@ -143,7 +143,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['pypy-3.10', '3.8', '3.9', '3.10', '3.11', '3.12']
+        python: ['pypy-3.10', '3.9', '3.10', '3.11', '3.12', '3.13']
     continue-on-error: >-
       ${{
         (
@@ -203,7 +203,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.8', '3.12']
+        include:
+          - python: '3.9'  # We support running on cython 2 and 3 for 3.9
+            cython: '<3'   # cython 2
+          - python: '3.9'
+            cython: '>=3'  # cython 3 (or greater)
+          - python: '3.11' # 3.11 is the last version Cy2 supports
+            cython: '<3'   # cython 2
+          - python: '3.13' # We support running cython3 on 3.13
+            cython: '>=3'  # cython 3 (or greater)
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -216,18 +224,11 @@ jobs:
       - name: install trio and setuptools
         run: python -m pip install --upgrade pip . setuptools
 
-      - name: install cython<3
-        run: python -m pip install "cython<3"
-      - name: compile pyx file
-        run: cythonize -i tests/cython/test_cython.pyx
-      - name: import & run module
-        run: python -c 'import tests.cython.test_cython'
+      - name: install cython & compile pyx file
+        run: |
+          python -m pip install "cython${{ matrix.cython }}"
+          cythonize --inplace tests/cython/test_cython.pyx
 
-      - name: install cython>=3
-        run: python -m pip install "cython>=3"
-      - name: compile pyx file
-        # different cython version should trigger a re-compile, but --force just in case
-        run: cythonize --inplace --force tests/cython/test_cython.pyx
       - name: import & run module
         run: python -c 'import tests.cython.test_cython'
 

.github/workflows/release.yml

@@ -12,7 +12,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.8"
+          python-version: "3.9"
       - run: python -m pip install build
       - run: python -m build
 

README.rst

@@ -92,7 +92,7 @@ demonstration of implementing the "Happy Eyeballs" algorithm in an
 older library versus Trio.
 
 **Cool, but will it work on my system?** Probably! As long as you have
-some kind of Python 3.8-or-better (CPython or `currently maintained versions of
+some kind of Python 3.9-or-better (CPython or `currently maintained versions of
 PyPy3 <https://doc.pypy.org/en/latest/faq.html#which-python-versions-does-pypy-implement>`__
 are both fine), and are using Linux, macOS, Windows, or FreeBSD, then Trio
 will work. Other environments might work too, but those

check.sh

@@ -78,7 +78,7 @@ fi
 
 # Check pip compile is consistent
 echo "::group::Pip Compile - Tests"
-uv pip compile --universal --python-version=3.8 test-requirements.in -o test-requirements.txt
+uv pip compile --universal --python-version=3.9 test-requirements.in -o test-requirements.txt
 echo "::endgroup::"
 echo "::group::Pip Compile - Docs"
 uv pip compile --universal --python-version=3.11 docs-requirements.in -o docs-requirements.txt

docs/source/index.rst

@@ -45,7 +45,7 @@ Vital statistics:
 
 * Supported environments: We test on
 
-  - Python: 3.8+ (CPython and PyPy)
+  - Python: 3.9+ (CPython and PyPy)
   - Windows, macOS, Linux (glibc and musl), FreeBSD
 
   Other environments might also work; give it a try and see.

docs/source/tutorial.rst

@@ -88,7 +88,7 @@ Okay, ready? Let's get started.
 Before you begin
 ----------------
 
-1. Make sure you're using Python 3.8 or newer.
+1. Make sure you're using Python 3.9 or newer.
 
 2. ``python3 -m pip install --upgrade trio`` (or on Windows, maybe
    ``py -3 -m pip install --upgrade trio`` – `details

newsfragments/3106.removal.rst

@@ -0,0 +1 @@
+Drop support for Python 3.8. (`#3104 <https://github.com/python-trio/trio/issues/3104>`__)

pyproject.toml

@@ -26,7 +26,6 @@ classifiers = [
     "Programming Language :: Python :: Implementation :: CPython",
     "Programming Language :: Python :: Implementation :: PyPy",
     "Programming Language :: Python :: 3 :: Only",
-    "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
@@ -35,7 +34,7 @@ classifiers = [
     "Topic :: System :: Networking",
     "Typing :: Typed",
 ]
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 dependencies = [
     # attrs 19.2.0 adds `eq` option to decorators
     # attrs 20.1.0 adds @frozen
@@ -75,7 +74,6 @@ include-package-data = true
 version = {attr = "trio._version.__version__"}
 
 [tool.black]
-target-version = ['py38']
 force-exclude = '''
 (
   ^/docs/source/reference-.*
@@ -170,7 +168,7 @@ combine-as-imports = true
 fixture-parentheses = false
 
 [tool.mypy]
-python_version = "3.8"
+python_version = "3.9"
 files = ["src/trio/", "docs/source/*.py"]
 
 # Be flexible about dependencies that don't have stubs yet (like pytest)
@@ -195,7 +193,7 @@ disallow_untyped_defs = true
 check_untyped_defs = true
 
 [tool.pyright]
-pythonVersion = "3.8"
+pythonVersion = "3.9"
 reportUnnecessaryTypeIgnoreComment = true
 typeCheckingMode = "strict"
 

src/trio/_channel.py

@@ -5,7 +5,6 @@
 from typing import (
     TYPE_CHECKING,
     Generic,
-    Tuple,  # only needed for typechecking on <3.9
 )
 
 import attrs
@@ -93,8 +92,7 @@ def _open_memory_channel(
 # it could replace the normal function header
 if TYPE_CHECKING:
     # written as a class so you can say open_memory_channel[int](5)
-    # Need to use Tuple instead of tuple due to CI check running on 3.8
-    class open_memory_channel(Tuple["MemorySendChannel[T]", "MemoryReceiveChannel[T]"]):
+    class open_memory_channel(tuple["MemorySendChannel[T]", "MemoryReceiveChannel[T]"]):
         def __new__(  # type: ignore[misc]  # "must return a subtype"
             cls,
             max_buffer_size: int | float,  # noqa: PYI041

src/trio/_core/_asyncgens.py

@@ -17,10 +17,9 @@
 
 if TYPE_CHECKING:
     from types import AsyncGeneratorType
-    from typing import Set
 
     _WEAK_ASYNC_GEN_SET = weakref.WeakSet[AsyncGeneratorType[object, NoReturn]]
-    _ASYNC_GEN_SET = Set[AsyncGeneratorType[object, NoReturn]]
+    _ASYNC_GEN_SET = set[AsyncGeneratorType[object, NoReturn]]
 else:
     _WEAK_ASYNC_GEN_SET = weakref.WeakSet
     _ASYNC_GEN_SET = set

src/trio/_core/_entry_queue.py

@@ -2,7 +2,8 @@
 
 import threading
 from collections import deque
-from typing import TYPE_CHECKING, Callable, NoReturn, Tuple
+from collections.abc import Callable
+from typing import TYPE_CHECKING, NoReturn
 
 import attrs
 
@@ -16,7 +17,7 @@
     PosArgsT = TypeVarTuple("PosArgsT")
 
 Function = Callable[..., object]
-Job = Tuple[Function, Tuple[object, ...]]
+Job = tuple[Function, tuple[object, ...]]
 
 
 @attrs.define

src/trio/_core/_generated_io_kqueue.py

@@ -4,13 +4,15 @@
 from __future__ import annotations
 
 import sys
-from typing import TYPE_CHECKING, Callable, ContextManager
+from typing import TYPE_CHECKING
 
 from ._ki import LOCALS_KEY_KI_PROTECTION_ENABLED
 from ._run import GLOBAL_RUN_CONTEXT
 
 if TYPE_CHECKING:
     import select
+    from collections.abc import Callable
+    from contextlib import AbstractContextManager
 
     from .. import _core
     from .._file_io import _HasFileNo
@@ -44,7 +46,7 @@ def current_kqueue() -> select.kqueue:
 def monitor_kevent(
     ident: int,
     filter: int,
-) -> ContextManager[_core.UnboundedQueue[select.kevent]]:
+) -> AbstractContextManager[_core.UnboundedQueue[select.kevent]]:
     """TODO: these are implemented, but are currently more of a sketch than
     anything real. See `#26
     <https://github.com/python-trio/trio/issues/26>`__.

src/trio/_core/_generated_io_windows.py

@@ -4,12 +4,14 @@
 from __future__ import annotations
 
 import sys
-from typing import TYPE_CHECKING, ContextManager
+from typing import TYPE_CHECKING
 
 from ._ki import LOCALS_KEY_KI_PROTECTION_ENABLED
 from ._run import GLOBAL_RUN_CONTEXT
 
 if TYPE_CHECKING:
+    from contextlib import AbstractContextManager
+
     from typing_extensions import Buffer
 
     from .._file_io import _HasFileNo
@@ -196,7 +198,9 @@ def current_iocp() -> int:
         raise RuntimeError("must be called from async context") from None
 
 
-def monitor_completion_key() -> ContextManager[tuple[int, UnboundedQueue[object]]]:
+def monitor_completion_key() -> (
+    AbstractContextManager[tuple[int, UnboundedQueue[object]]]
+):
     """TODO: these are implemented, but are currently more of a sketch than
     anything real. See `#26
     <https://github.com/python-trio/trio/issues/26>`__ and `#52

src/trio/_core/_instrumentation.py

@@ -1,6 +1,9 @@
+from __future__ import annotations
+
 import logging
 import types
-from typing import Any, Callable, Dict, Sequence, TypeVar
+from collections.abc import Callable, Sequence
+from typing import Any, TypeVar
 
 from .._abc import Instrument
 
@@ -17,7 +20,7 @@ def _public(fn: F) -> F:
     return fn
 
 
-class Instruments(Dict[str, Dict[Instrument, None]]):
+class Instruments(dict[str, dict[Instrument, None]]):
     """A collection of `trio.abc.Instrument` organized by hook.
 
     Instrumentation calls are rather expensive, and we don't want a

src/trio/_core/_io_kqueue.py

@@ -4,7 +4,7 @@
 import select
 import sys
 from contextlib import contextmanager
-from typing import TYPE_CHECKING, Callable, Iterator, Literal
+from typing import TYPE_CHECKING, Literal
 
 import attrs
 import outcome
@@ -14,6 +14,8 @@
 from ._wakeup_socketpair import WakeupSocketpair
 
 if TYPE_CHECKING:
+    from collections.abc import Callable, Iterator
+
     from typing_extensions import TypeAlias
 
     from .._core import Abort, RaiseCancelT, Task, UnboundedQueue

src/trio/_core/_io_windows.py

@@ -8,8 +8,6 @@
 from typing import (
     TYPE_CHECKING,
     Any,
-    Callable,
-    Iterator,
     Literal,
     TypeVar,
     cast,
@@ -41,6 +39,8 @@
 )
 
 if TYPE_CHECKING:
+    from collections.abc import Callable, Iterator
+
     from typing_extensions import Buffer, TypeAlias
 
     from .._file_io import _HasFileNo

src/trio/_core/_tests/test_guest_mode.py

@@ -11,14 +11,12 @@
 import time
 import traceback
 import warnings
+from collections.abc import AsyncGenerator, Awaitable, Callable
 from functools import partial
 from math import inf
 from typing import (
     TYPE_CHECKING,
     Any,
-    AsyncGenerator,
-    Awaitable,
-    Callable,
     NoReturn,
     TypeVar,
 )