WIP: Always pass errno argument for OSError subclasses

Include/internal/pycore_pyerrors.h

@@ -136,6 +136,16 @@ PyAPI_FUNC(void) _PyErr_SetString(
     PyObject *exception,
     const char *string);
 
+/*
+ * Raise an OSError subclass with an explicit errno value, so that the
+ * resulting exception has a meaningful errno attribute.  msg is used as
+ * strerror.  Prefer PyErr_SetFromErrno() when the C errno is already set.
+ */
+PyAPI_FUNC(void) _PyErr_SetOSErrorWithMessage(
+    PyObject *exception,
+    int err,
+    const char *msg);
+
 /*
  * Set an exception with the error message decoded from the current locale
  * encoding (LC_CTYPE).

Lib/_pyio.py

@@ -2626,7 +2626,7 @@ def read(self, size=None):
         if size < 0:
             chunk = self.buffer.read()
             if chunk is None:
-                raise BlockingIOError("Read returned None.")
+                raise BlockingIOError(errno.EAGAIN, "Read returned None.")
             # Read everything.
             result = (self._get_decoded_chars() +
                       decoder.decode(chunk, final=True))

Lib/asyncio/base_events.py

@@ -1183,7 +1183,8 @@ async def create_connection(
                             ', '.join(str(exc) for exc in exceptions)))
                     else:
                         # No exceptions were collected, raise a timeout error
-                        raise TimeoutError('create_connection failed')
+                        raise TimeoutError(errno.ETIMEDOUT,
+                                           'create_connection failed')
                 finally:
                     exceptions = None
 

Lib/asyncio/base_subprocess.py

@@ -1,4 +1,6 @@
 import collections
+import errno
+import os
 import subprocess
 import warnings
 import os
@@ -148,7 +150,7 @@ def get_pipe_transport(self, fd):
 
     def _check_proc(self):
         if self._proc is None:
-            raise ProcessLookupError()
+            raise ProcessLookupError(errno.ESRCH, os.strerror(errno.ESRCH))
 
     if sys.platform == 'win32':
         def send_signal(self, signal):

Lib/asyncio/proactor_events.py

@@ -6,6 +6,7 @@
 
 __all__ = 'BaseProactorEventLoop',
 
+import errno
 import io
 import os
 import socket
@@ -449,7 +450,7 @@ def _pipe_closed(self, fut):
         assert fut is self._read_fut, (fut, self._read_fut)
         self._read_fut = None
         if self._write_fut is not None:
-            self._force_close(BrokenPipeError())
+            self._force_close(BrokenPipeError(errno.EPIPE, os.strerror(errno.EPIPE)))
         else:
             self.close()
 

Lib/asyncio/sslproto.py

@@ -4,6 +4,8 @@
 
 import collections
 import enum
+import errno
+import os
 import warnings
 try:
     import ssl
@@ -464,7 +466,7 @@ def eof_received(self):
                 logger.debug("%r received EOF", self)
 
             if self._state == SSLProtocolState.DO_HANDSHAKE:
-                self._on_handshake_complete(ConnectionResetError)
+                self._on_handshake_complete(ConnectionResetError(errno.ECONNRESET, os.strerror(errno.ECONNRESET)))
 
             elif self._state == SSLProtocolState.WRAPPED:
                 self._set_state(SSLProtocolState.FLUSHING)
@@ -556,7 +558,7 @@ def _check_handshake_timeout(self):
                 f"{self._ssl_handshake_timeout} seconds: "
                 f"aborting the connection"
             )
-            self._fatal_error(ConnectionAbortedError(msg))
+            self._fatal_error(ConnectionAbortedError(errno.ECONNABORTED, msg))
 
     def _do_handshake(self):
         try:
@@ -644,7 +646,8 @@ def _check_shutdown_timeout(self):
             )
         ):
             self._transport._force_close(
-                exceptions.TimeoutError('SSL shutdown timed out'))
+                exceptions.TimeoutError(errno.ETIMEDOUT,
+                                        'SSL shutdown timed out'))
 
     def _do_flush(self):
         self._do_read()

Lib/asyncio/streams.py

@@ -3,6 +3,7 @@
     'open_connection', 'start_server')
 
 import collections
+import errno
 import socket
 import sys
 import warnings
@@ -163,7 +164,7 @@ def connection_lost(self, exc):
 
     async def _drain_helper(self):
         if self._connection_lost:
-            raise ConnectionResetError('Connection lost')
+            raise ConnectionResetError(errno.ECONNRESET, 'Connection lost')
         if not self._paused:
             return
         waiter = self._loop.create_future()

Lib/asyncio/tasks.py

@@ -12,10 +12,12 @@
 
 import concurrent.futures
 import contextvars
+import errno
 import functools
 import inspect
 import itertools
 import math
+import os
 import types
 import weakref
 from types import GenericAlias
@@ -480,7 +482,7 @@ async def wait_for(fut, timeout):
         try:
             return fut.result()
         except exceptions.CancelledError as exc:
-            raise TimeoutError from exc
+            raise TimeoutError(errno.ETIMEDOUT, os.strerror(errno.ETIMEDOUT)) from exc
 
     async with timeouts.timeout(timeout):
         return await fut
@@ -613,7 +615,8 @@ async def _wait_for_one(self, resolve=False):
         f = await self._done.get()
         if f is None:
             # Dummy value from _handle_timeout().
-            raise exceptions.TimeoutError
+            raise exceptions.TimeoutError(errno.ETIMEDOUT,
+                                          os.strerror(errno.ETIMEDOUT))
         return f.result() if resolve else f
 
 

Lib/asyncio/timeouts.py

@@ -1,4 +1,5 @@
 import enum
+import errno
 
 from types import TracebackType
 
@@ -112,7 +113,7 @@ async def __aexit__(
                 # Since there are no new cancel requests, we're
                 # handling this.
                 if issubclass(exc_type, exceptions.CancelledError):
-                    raise TimeoutError from exc_val
+                    raise TimeoutError(errno.ETIMEDOUT, 'timed out') from exc_val
                 elif exc_val is not None:
                     self._insert_timeout_error(exc_val)
                     if isinstance(exc_val, ExceptionGroup):
@@ -134,7 +135,7 @@ def _on_timeout(self) -> None:
     def _insert_timeout_error(exc_val: BaseException) -> None:
         while exc_val.__context__ is not None:
             if isinstance(exc_val.__context__, exceptions.CancelledError):
-                te = TimeoutError()
+                te = TimeoutError(errno.ETIMEDOUT, 'timed out')
                 te.__context__ = te.__cause__ = exc_val.__context__
                 exc_val.__context__ = te
                 break

Lib/asyncio/unix_events.py

@@ -730,7 +730,7 @@ def _read_ready(self):
         if self._loop.get_debug():
             logger.info("%r was closed by peer", self)
         if self._buffer:
-            self._close(BrokenPipeError())
+            self._close(BrokenPipeError(errno.EPIPE, os.strerror(errno.EPIPE)))
         else:
             self._close()
 

Lib/concurrent/futures/_base.py

@@ -4,7 +4,9 @@
 __author__ = 'Brian Quinlan (brian@sweetapp.com)'
 
 import collections
+import errno
 import logging
+import os
 import threading
 import time
 import types
@@ -231,6 +233,7 @@ def as_completed(fs, timeout=None):
                 wait_timeout = end_time - time.monotonic()
                 if wait_timeout < 0:
                     raise TimeoutError(
+                            errno.ETIMEDOUT,
                             '%d (of %d) futures unfinished' % (
                             len(pending), total_futures))
 
@@ -460,7 +463,7 @@ def result(self, timeout=None):
                 elif self._state == FINISHED:
                     return self.__get_result()
                 else:
-                    raise TimeoutError()
+                    raise TimeoutError(errno.ETIMEDOUT, os.strerror(errno.ETIMEDOUT))
         finally:
             # Break a reference cycle with the exception in self._exception
             self = None
@@ -496,7 +499,7 @@ def exception(self, timeout=None):
             elif self._state == FINISHED:
                 return self._exception
             else:
-                raise TimeoutError()
+                raise TimeoutError(errno.ETIMEDOUT, os.strerror(errno.ETIMEDOUT))
 
     # The following methods should only be used by Executors and in tests.
     def set_running_or_notify_cancel(self):

Lib/hashlib.py

@@ -53,6 +53,8 @@
     '031edd7d41651593c5fe5c006fa5752b37fddff7bc4e843aa6af0c950f4b9406'
 """
 
+import errno
+
 # This tuple and __get_builtin_constructor() must be modified if a new
 # always available algorithm is added.
 __always_supported = ('md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512',
@@ -253,7 +255,8 @@ def file_digest(fileobj, digest, /, *, _bufsize=2**18):
     while True:
         size = fileobj.readinto(buf)
         if size is None:
-            raise BlockingIOError("I/O operation would block.")
+            raise BlockingIOError(errno.EAGAIN,
+                                  "I/O operation would block.")
         if size == 0:
             break  # EOF
         digestobj.update(view[:size])

Lib/importlib/resources/_adapters.py

@@ -1,3 +1,4 @@
+import errno
 from contextlib import suppress
 from io import TextIOWrapper
 
@@ -136,7 +137,7 @@ def name(self):
             return self._path[-1]
 
         def open(self, mode='r', *args, **kwargs):
-            raise FileNotFoundError("Can't open orphan path")
+            raise FileNotFoundError(errno.ENOENT, "Can't open orphan path")
 
     def __init__(self, spec):
         self.spec = spec

Lib/importlib/resources/abc.py

@@ -1,4 +1,5 @@
 import abc
+import errno
 import itertools
 import os
 import pathlib
@@ -34,7 +35,7 @@ def open_resource(self, resource: Text) -> BinaryIO:
         # This deliberately raises FileNotFoundError instead of
         # NotImplementedError so that if this method is accidentally called,
         # it'll still do the right thing.
-        raise FileNotFoundError
+        raise FileNotFoundError(errno.ENOENT, 'No such resource')
 
     @abc.abstractmethod
     def resource_path(self, resource: Text) -> Text:
@@ -47,20 +48,20 @@ def resource_path(self, resource: Text) -> Text:
         # This deliberately raises FileNotFoundError instead of
         # NotImplementedError so that if this method is accidentally called,
         # it'll still do the right thing.
-        raise FileNotFoundError
+        raise FileNotFoundError(errno.ENOENT, 'No such resource')
 
     @abc.abstractmethod
     def is_resource(self, path: Text) -> bool:
         """Return True if the named 'path' is a resource.
 
         Files are resources, directories are not.
         """
-        raise FileNotFoundError
+        raise FileNotFoundError(errno.ENOENT, 'No such resource')
 
     @abc.abstractmethod
     def contents(self) -> Iterable[str]:
         """Return an iterable of entries in `package`."""
-        raise FileNotFoundError
+        raise FileNotFoundError(errno.ENOENT, 'No such resource')
 
 
 class TraversalError(Exception):
@@ -180,7 +181,7 @@ def open_resource(self, resource: StrPath) -> BinaryIO:
         return self.files().joinpath(resource).open('rb')
 
     def resource_path(self, resource: Any) -> NoReturn:
-        raise FileNotFoundError(resource)
+        raise FileNotFoundError(errno.ENOENT, 'No such resource', resource)
 
     def is_resource(self, path: StrPath) -> bool:
         return self.files().joinpath(path).is_file()

Lib/importlib/resources/readers.py

@@ -2,6 +2,7 @@
 
 import collections
 import contextlib
+import errno
 import itertools
 import operator
 import pathlib
@@ -46,7 +47,10 @@ def open_resource(self, resource):
         try:
             return super().open_resource(resource)
         except KeyError as exc:
-            raise FileNotFoundError(exc.args[0])
+            if resource == exc.args[0]:
+                raise FileNotFoundError(errno.ENOENT, 'No such resource', resource)
+            else:
+                raise FileNotFoundError(errno.ENOENT, exc.args[0])
 
     def is_resource(self, path):
         """
@@ -72,9 +76,11 @@ def __init__(self, *paths):
         self._paths = list(map(_ensure_traversable, remove_duplicates(paths)))
         if not self._paths:
             message = 'MultiplexedPath must contain at least one path'
-            raise FileNotFoundError(message)
-        if not all(path.is_dir() for path in self._paths):
-            raise NotADirectoryError('MultiplexedPath only supports directories')
+            raise FileNotFoundError(errno.ENOENT, message)
+        for path in self._paths:
+            if not path.is_dir():
+                message = 'MultiplexedPath only supports directories'
+                raise NotADirectoryError(errno.ENOTDIR, message, path)
 
     def iterdir(self):
         children = (child for path in self._paths for child in path.iterdir())
@@ -83,10 +89,10 @@ def iterdir(self):
         return map(self._follow, (locs for name, locs in groups))
 
     def read_bytes(self):
-        raise FileNotFoundError(f'{self} is not a file')
+        raise FileNotFoundError(errno.ENOENT, f'{self} is not a file')
 
     def read_text(self, *args, **kwargs):
-        raise FileNotFoundError(f'{self} is not a file')
+        raise FileNotFoundError(errno.ENOENT, f'{self} is not a file')
 
     def is_dir(self):
         return True
@@ -122,7 +128,7 @@ def _follow(cls, children):
                 return next(one_file)
 
     def open(self, *args, **kwargs):
-        raise FileNotFoundError(f'{self} is not a file')
+        raise FileNotFoundError(errno.ENOENT, f'{self} is not a file')
 
     @property
     def name(self):

Lib/importlib/resources/simple.py

@@ -3,8 +3,10 @@
 """
 
 import abc
+import errno
 import io
 import itertools
+import os
 from typing import BinaryIO
 
 from .abc import Traversable, TraversableResources
@@ -67,7 +69,7 @@ def iterdir(self):
         return itertools.chain(files, dirs)
 
     def open(self, *args, **kwargs):
-        raise IsADirectoryError()
+        raise IsADirectoryError(errno.EISDIR, os.strerror(errno.EISDIR))
 
 
 class ResourceHandle(Traversable):

Lib/logging/config.py

@@ -65,7 +65,7 @@ def fileConfig(fname, defaults=None, disable_existing_loggers=True, encoding=Non
 
     if isinstance(fname, str):
         if not os.path.exists(fname):
-            raise FileNotFoundError(f"{fname} doesn't exist")
+            raise FileNotFoundError(errno.ENOENT, 'No such file', fname)
         elif not os.path.getsize(fname):
             raise RuntimeError(f'{fname} is an empty file')