Drop Python 3.5 (third take)

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.5', '3.6', '3.7', '3.8']
+        python: ['3.6', '3.7', '3.8']
         arch: ['x86', 'x64']
         lsp: ['']
         extra_name: ['']
@@ -46,7 +46,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.5', '3.6', '3.7', '3.8']
+        python: ['3.6', '3.7', '3.8']
         check_docs: ['0']
         check_formatting: ['0']
         extra_name: ['']
@@ -79,7 +79,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.5', '3.6', '3.7', '3.8']
+        python: ['3.6', '3.7', '3.8']
     steps:
       - name: Checkout
         uses: actions/checkout@v2

.travis.yml

@@ -21,13 +21,7 @@ jobs:
       env:
         - "JOB_NAME='Ubuntu 19.10, full VM'"
         - "VM_IMAGE=https://cloud-images.ubuntu.com/eoan/current/eoan-server-cloudimg-amd64.img"
-    # 3.5.0 and 3.5.1 have different __aiter__ semantics than all
-    # other versions, so we need to test them specially. Travis's
-    # newer images only provide 3.5.2+, so we have to request the old
-    # 'trusty' images.
-    - python: 3.5.0
-      dist: trusty
-    - python: 3.5-dev
+    - python: 3.6.1  # earliest 3.6 version available on Travis
     - python: 3.6-dev
     - python: 3.7-dev
     - python: 3.8-dev

README.rst

@@ -102,7 +102,7 @@ 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 3.5-or-better (CPython or the latest PyPy3 are
+some kind of Python 3.6-or-better (CPython or the latest PyPy3 are
 both fine), and are using Linux, macOS, or Windows, then Trio should
 absolutely work. *BSD and illumos likely work too, but we don't have
 testing infrastructure for them. And all of our dependencies are pure

ci.sh

@@ -55,10 +55,6 @@ if [ "$AGENT_OS" = "Windows_NT" ]; then
 
     pydir="$PWD/pyinstall/${PYTHON_PKG}"
     export PATH="${pydir}/tools:${pydir}/tools/scripts:$PATH"
-
-    # Fix an issue with the nuget python 3.5 packages
-    # https://github.com/python-trio/trio/pull/827#issuecomment-457433940
-    rm -f "${pydir}/tools/pyvenv.cfg" || true
 fi
 
 ### Travis + macOS ###

docs/source/index.rst

@@ -44,7 +44,7 @@ chance to give feedback about any compatibility-breaking changes.
 Vital statistics:
 
 * Supported environments: Linux, macOS, or Windows running some kind of Python
-  3.5-or-better (either CPython or PyPy3 is fine). \*BSD and
+  3.6-or-better (either CPython or PyPy3 is fine). \*BSD and
   illumos likely work too, but are untested.
 
 * Install: ``python3 -m pip install -U trio`` (or on Windows, maybe

docs/source/tutorial.rst

@@ -94,7 +94,7 @@ Okay, ready? Let's get started.
 Before you begin
 ----------------
 
-1. Make sure you're using Python 3.5 or newer.
+1. Make sure you're using Python 3.6 or newer.
 
 2. ``python3 -m pip install --upgrade trio`` (or on Windows, maybe
    ``py -3 -m pip install --upgrade trio`` – `details
@@ -312,7 +312,7 @@ runs:
    >>>> # but forcing a garbage collection gives us a warning:
    >>>> import gc
    >>>> gc.collect()
-   /home/njs/pypy-3.5-nightly/lib-python/3/importlib/_bootstrap.py:191: RuntimeWarning: coroutine 'sleep' was never awaited
+   /home/njs/pypy-3.8-nightly/lib-python/3/importlib/_bootstrap.py:191: RuntimeWarning: coroutine 'sleep' was never awaited
    if _module_locks.get(name) is wr:    # XXX PyPy fix?
    0
    >>>>

newsfragments/75.removal.rst

@@ -0,0 +1 @@
+Remove support for Python 3.5.

setup.cfg

@@ -3,3 +3,4 @@ xfail_strict = true
 faulthandler_timeout=60
 markers =
     redistributors_should_skip: tests that should be skipped by downstream redistributors
+junit_family = xunit2

setup.py

@@ -44,7 +44,7 @@
 Vital statistics:
 
 * Supported environments: Linux, macOS, or Windows running some kind of Python
-  3.5-or-better (either CPython or PyPy3 is fine). \\*BSD and illumos likely
+  3.6-or-better (either CPython or PyPy3 is fine). \\*BSD and illumos likely
   work too, but are not tested.
 
 * Install: ``python3 -m pip install -U trio`` (or on Windows, maybe
@@ -93,7 +93,7 @@
     # This means, just install *everything* you see under trio/, even if it
     # doesn't look like a source file, so long as it appears in MANIFEST.in:
     include_package_data=True,
-    python_requires=">=3.5",
+    python_requires=">=3.6",
     keywords=["async", "io", "networking", "trio"],
     classifiers=[
         "Development Status :: 3 - Alpha",
@@ -107,8 +107,9 @@
         "Programming Language :: Python :: Implementation :: CPython",
         "Programming Language :: Python :: Implementation :: PyPy",
         "Programming Language :: Python :: 3 :: Only",
-        "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
         "Topic :: System :: Networking",
         "Framework :: Trio",
     ],

trio/__init__.py

@@ -169,10 +169,3 @@
     __name__ + ".subprocess", _deprecated_subprocess_reexports.__dict__
 )
 del fixup_module_metadata
-
-import sys
-if sys.version_info < (3, 6):
-    _deprecate.warn_deprecated(
-        "Support for Python 3.5", "0.14", issue=75, instead="Python 3.6+"
-    )
-del sys

trio/_abc.py

@@ -1,6 +1,5 @@
 from abc import ABCMeta, abstractmethod
 from typing import Generic, TypeVar
-from ._util import aiter_compat
 import trio
 
 
@@ -414,7 +413,6 @@ async def receive_some(self, max_bytes=None):
 
         """
 
-    @aiter_compat
     def __aiter__(self):
         return self
 
@@ -629,7 +627,6 @@ async def receive(self) -> ReceiveType:
 
         """
 
-    @aiter_compat
     def __aiter__(self):
         return self
 

trio/_core/_entry_queue.py

@@ -178,9 +178,7 @@ def run_sync_soon(self, sync_fn, *args, idempotent=False):
         If ``idempotent=True``, then ``sync_fn`` and ``args`` must be
         hashable, and Trio will make a best-effort attempt to discard any
         call submission which is equal to an already-pending call. Trio
-        will make an attempt to process these in first-in first-out order,
-        but no guarantees. (Currently processing is FIFO on CPython 3.6 and
-        PyPy, but not CPython 3.5.)
+        will process these in first-in first-out order.
 
         Any ordering guarantees apply separately to ``idempotent=False``
         and ``idempotent=True`` calls; there's no rule for how calls in the

trio/_core/_run.py

@@ -60,7 +60,7 @@ def _public(fn):
 
 
 # On 3.7+, Context.run() is implemented in C and doesn't show up in
-# tracebacks. On 3.6 and earlier, we use the contextvars backport, which is
+# tracebacks. On 3.6, we use the contextvars backport, which is
 # currently implemented in Python and adds 1 frame to tracebacks. So this
 # function is a super-overkill version of "0 if sys.version_info >= (3, 7)
 # else 1". But if Context.run ever changes, we'll be ready!
@@ -1256,12 +1256,9 @@ def _return_value_looks_like_wrong_library(value):
             # The protocol for detecting an asyncio Future-like object
             if getattr(value, "_asyncio_future_blocking", None) is not None:
                 return True
-            # asyncio.Future doesn't have _asyncio_future_blocking until
-            # 3.5.3. We don't want to import asyncio, but this janky check
-            # should work well enough for our purposes. And it also catches
-            # tornado Futures and twisted Deferreds. By the time we're calling
-            # this function, we already know something has gone wrong, so a
-            # heuristic is pretty safe.
+            # This janky check catches tornado Futures and twisted Deferreds.
+            # By the time we're calling this function, we already know
+            # something has gone wrong, so a heuristic is pretty safe.
             if value.__class__.__name__ in ("Future", "Deferred"):
                 return True
             return False
@@ -1909,7 +1906,7 @@ def run_impl(runner, async_fn, args):
             try:
                 # We used to unwrap the Outcome object here and send/throw its
                 # contents in directly, but it turns out that .throw() is
-                # buggy, at least on CPython 3.6 and earlier:
+                # buggy, at least on CPython 3.6:
                 #   https://bugs.python.org/issue29587
                 #   https://bugs.python.org/issue29590
                 # So now we send in the Outcome object and unwrap it on the

trio/_core/_unbounded_queue.py

@@ -1,7 +1,6 @@
 import attr
 
 from .. import _core
-from .._util import aiter_compat
 from .._deprecate import deprecated
 
 __all__ = ["UnboundedQueue"]
@@ -146,7 +145,6 @@ def statistics(self):
             tasks_waiting=self._lot.statistics().tasks_waiting
         )
 
-    @aiter_compat
     def __aiter__(self):
         return self
 

trio/_core/_windows_cffi.py

@@ -1,10 +1,6 @@
 import cffi
 import re
 import enum
-try:
-    from enum import IntFlag
-except ImportError:  # python 3.5
-    from enum import IntEnum as IntFlag
 
 ################################################################
 # Functions and types
@@ -264,7 +260,7 @@ class FileFlags(enum.IntEnum):
     TRUNCATE_EXISTING = 5
 
 
-class AFDPollFlags(IntFlag):
+class AFDPollFlags(enum.IntFlag):
     # These are drawn from a combination of:
     #   https://github.com/piscisaureus/wepoll/blob/master/src/afd.h
     #   https://github.com/reactos/reactos/blob/master/sdk/include/reactos/drivers/afd/shared.h
@@ -289,7 +285,7 @@ class WSAIoctls(enum.IntEnum):
     SIO_BSP_HANDLE_SELECT = 0x4800001C
 
 
-class CompletionModes(IntFlag):
+class CompletionModes(enum.IntFlag):
     FILE_SKIP_COMPLETION_PORT_ON_SUCCESS = 0x1
     FILE_SKIP_SET_EVENT_ON_HANDLE = 0x2
 

trio/_core/tests/test_ki.py

@@ -176,11 +176,30 @@ async def agen_unprotected2():
         finally:
             assert not _core.currently_ki_protected()
 
+    # Native async generators
+    @_core.enable_ki_protection
+    async def agen_protected3():
+        assert _core.currently_ki_protected()
+        try:
+            yield
+        finally:
+            assert _core.currently_ki_protected()
+
+    @_core.disable_ki_protection
+    async def agen_unprotected3():
+        assert not _core.currently_ki_protected()
+        try:
+            yield
+        finally:
+            assert not _core.currently_ki_protected()
+
     for agen_fn in [
         agen_protected1,
         agen_protected2,
+        agen_protected3,
         agen_unprotected1,
         agen_unprotected2,
+        agen_unprotected3,
     ]:
         async for _ in agen_fn():  # noqa
             assert not _core.currently_ki_protected()
@@ -504,9 +523,7 @@ def test_ki_wakes_us_up():
     #
     # which contains the desired sequence.
     #
-    # Affected version of CPython include:
-    # - all versions of 3.5 (fix will not be backported)
-    # - 3.6.1 and earlier
+    # Affected version of CPython include 3.6.1 and earlier.
     # It's fixed in 3.6.2 and 3.7+
     #
     # PyPy was never affected.

trio/_core/tests/test_run.py

@@ -14,13 +14,11 @@
 import outcome
 import sniffio
 import pytest
-from async_generator import async_generator
 
 from .tutil import slow, check_sequence_matches, gc_collect_harder
 from ... import _core
 from ..._threads import to_thread_run_sync
 from ..._timeouts import sleep, fail_after
-from ..._util import aiter_compat
 from ...testing import (
     wait_all_tasks_blocked,
     Sequencer,
@@ -38,9 +36,7 @@ async def sleep_forever():
 # Some of our tests need to leak coroutines, and thus trigger the
 # "RuntimeWarning: coroutine '...' was never awaited" message. This context
 # manager should be used anywhere this happens to hide those messages, because
-# (a) when expected they're clutter, (b) on CPython 3.5.x where x < 3, this
-# warning can trigger a segfault if we run with warnings turned into errors:
-#   https://bugs.python.org/issue27811
+# when expected they're clutter.
 @contextmanager
 def ignore_coroutine_never_awaited_warnings():
     with warnings.catch_warnings():
@@ -1380,13 +1376,7 @@ def cb(x):
         for i in range(100):
             token.run_sync_soon(cb, i, idempotent=True)
     await wait_all_tasks_blocked()
-    if (
-        sys.version_info < (3, 6)
-        and platform.python_implementation() == "CPython"
-    ):
-        # no order guarantees
-        record.sort()
-    # Otherwise, we guarantee FIFO
+    # We guarantee FIFO
     assert record == list(range(100))
 
 
@@ -1762,9 +1752,8 @@ def generator_based_coro():  # pragma: no cover
                 bad_call(len, [1, 2, 3])
             assert "appears to be synchronous" in str(excinfo.value)
 
-            @async_generator
             async def async_gen(arg):  # pragma: no cover
-                pass
+                yield
 
             with pytest.raises(TypeError) as excinfo:
                 bad_call(async_gen, 0)
@@ -2049,7 +2038,6 @@ def __init__(self, *largs):
         async def _accumulate(self, f, items, i):
             items[i] = await f()
 
-        @aiter_compat
         def __aiter__(self):
             return self
 
@@ -2389,23 +2377,10 @@ def test_async_function_implemented_in_C():
     # These used to crash because we'd try to mutate the coroutine object's
     # cr_frame, but C functions don't have Python frames.
 
-    ns = {"_core": _core}
-    try:
-        exec(
-            dedent(
-                """
-                async def agen_fn(record):
-                    assert not _core.currently_ki_protected()
-                    record.append("the generator ran")
-                    yield
-                """
-            ),
-            ns,
-        )
-    except SyntaxError:
-        pytest.skip("Requires Python 3.6+")
-    else:
-        agen_fn = ns["agen_fn"]
+    async def agen_fn(record):
+        assert not _core.currently_ki_protected()
+        record.append("the generator ran")
+        yield
 
     run_record = []
     agen = agen_fn(run_record)

trio/_deprecated_ssl_reexports.py

@@ -15,15 +15,10 @@
     cert_time_to_seconds, CertificateError, create_default_context,
     DER_cert_to_PEM_cert, get_default_verify_paths, match_hostname,
     PEM_cert_to_DER_cert, Purpose, SSLEOFError, SSLError, SSLSyscallError,
-    SSLZeroReturnError
+    SSLZeroReturnError, AlertDescription, SSLErrorNumber, SSLSession,
+    VerifyFlags, VerifyMode, Options
 )
 
-# Added in python 3.6
-try:
-    from ssl import AlertDescription, SSLErrorNumber, SSLSession, VerifyFlags, VerifyMode, Options  # noqa
-except ImportError:
-    pass
-
 # Added in python 3.7
 try:
     from ssl import SSLCertVerificationError, TLSVersion  # noqa