gh-109714: Pass the file name and a message when raising OSError subclasses

* Pass the file name as the filename argument instead of interpolating it
  into the message, so that it is available as the filename attribute:
  in shutil, logging.config, turtle, zipfile.Path and importlib.resources.
* Give an explicit message where the one derived from errno would be
  misleading: "timed out" for timeouts which are not connection timeouts,
  and "No such resource" in importlib.resources.
* In Tools, which is run with older Pythons too, pass errno explicitly.
* Add _PyErr_SetOSErrorWithMessage() for raising an OSError subclass with
  an errno which is not the default one of the class.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: serhiy-storchaka

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/asyncio/tasks.py

@@ -480,7 +480,7 @@ async def wait_for(fut, timeout):
         try:
             return fut.result()
         except exceptions.CancelledError as exc:
-            raise TimeoutError from exc
+            raise TimeoutError('timed out') from exc
 
     async with timeouts.timeout(timeout):
         return await fut
@@ -613,7 +613,7 @@ 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('timed out')
         return f.result() if resolve else f
 
 

Lib/asyncio/timeouts.py

@@ -112,7 +112,7 @@ 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('timed out') from exc_val
                 elif exc_val is not None:
                     self._insert_timeout_error(exc_val)
                     if isinstance(exc_val, ExceptionGroup):
@@ -134,7 +134,7 @@ 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('timed out')
                 te.__context__ = te.__cause__ = exc_val.__context__
                 exc_val.__context__ = te
                 break

Lib/concurrent/futures/_base.py

@@ -460,7 +460,7 @@ def result(self, timeout=None):
                 elif self._state == FINISHED:
                     return self.__get_result()
                 else:
-                    raise TimeoutError()
+                    raise TimeoutError('timed out')
         finally:
             # Break a reference cycle with the exception in self._exception
             self = None
@@ -496,7 +496,7 @@ def exception(self, timeout=None):
             elif self._state == FINISHED:
                 return self._exception
             else:
-                raise TimeoutError()
+                raise TimeoutError('timed out')
 
     # The following methods should only be used by Executors and in tests.
     def set_running_or_notify_cancel(self):

Lib/importlib/resources/abc.py

@@ -34,7 +34,7 @@ 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('No such resource')
 
     @abc.abstractmethod
     def resource_path(self, resource: Text) -> Text:
@@ -47,20 +47,20 @@ 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('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('No such resource')
 
     @abc.abstractmethod
     def contents(self) -> Iterable[str]:
         """Return an iterable of entries in `package`."""
-        raise FileNotFoundError
+        raise FileNotFoundError('No such resource')
 
 
 class TraversalError(Exception):
@@ -180,7 +180,7 @@ 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('No such resource', filename=resource)
 
     def is_resource(self, path: StrPath) -> bool:
         return self.files().joinpath(path).is_file()

Lib/importlib/resources/readers.py

@@ -46,7 +46,10 @@ 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('No such resource', filename=resource)
+            else:
+                raise FileNotFoundError(exc.args[0])
 
     def is_resource(self, path):
         """
@@ -73,8 +76,10 @@ def __init__(self, *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')
+        for path in self._paths:
+            if not path.is_dir():
+                message = 'MultiplexedPath only supports directories'
+                raise NotADirectoryError(message, filename=path)
 
     def iterdir(self):
         children = (child for path in self._paths for child in path.iterdir())

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('No such file', filename=fname)
         elif not os.path.getsize(fname):
             raise RuntimeError(f'{fname} is an empty file')
 

Lib/multiprocessing/pool.py

@@ -792,7 +792,7 @@ def wait(self, timeout=None):
     def get(self, timeout=None):
         self.wait(timeout)
         if not self.ready():
-            raise TimeoutError
+            raise TimeoutError('timed out')
         if self._success:
             return self._value
         else:
@@ -893,7 +893,7 @@ def next(self, timeout=None):
                 except IndexError:
                     if self._index == self._length:
                         self._stop_iterator()
-                    raise TimeoutError from None
+                    raise TimeoutError('timed out') from None
 
         if self._buffersize_sema is not None:
             self._buffersize_sema.release()

Lib/shutil.py

@@ -362,7 +362,8 @@ def copyfile(src, dst, *, follow_symlinks=True):
             # Issue 43219, raise a less confusing exception
             except IsADirectoryError as e:
                 if not os.path.exists(dst):
-                    raise FileNotFoundError(f'Directory does not exist: {dst}') from e
+                    raise FileNotFoundError('Directory does not exist',
+                                            filename=dst) from e
                 else:
                     raise
 
@@ -948,9 +949,8 @@ def move(src, dst, copy_function=copy2):
             if (_is_immutable(src)
                     or (not os.access(src, os.W_OK) and os.listdir(src)
                         and sys.platform == 'darwin')):
-                raise PermissionError("Cannot move the non-empty directory "
-                                      "'%s': Lacking write permission to '%s'."
-                                      % (src, src))
+                raise PermissionError("Cannot move the non-empty directory: "
+                                      "Lacking write permission", filename=src)
             copytree(src, real_dst, copy_function=copy_function,
                      symlinks=True)
             rmtree(src)

Lib/test/test_turtle.py

@@ -510,7 +510,8 @@ def test_save_raises_if_parent_not_found(self) -> None:
 
         with tempfile.TemporaryDirectory() as tmpdir:
             parent = os.path.join(tmpdir, "unknown_parent")
-            msg = f"The directory '{parent}' does not exist. Cannot save to it"
+            msg = ("The directory does not exist. Cannot save to it: "
+                   f"'{parent}'")
 
             with self.assertRaisesRegex(FileNotFoundError, re.escape(msg)):
                 turtle.TurtleScreen.save(screen, os.path.join(parent, "a.ps"))
@@ -524,8 +525,9 @@ def test_save_raises_if_file_found(self) -> None:
                 f.write("some text")
 
             msg = (
-                f"The file '{file_path}' already exists. To overwrite it use"
-                " the 'overwrite=True' argument of the save function."
+                "The file already exists. To overwrite it use"
+                " the 'overwrite=True' argument of the save function: "
+                f"'{file_path}'"
             )
             with self.assertRaisesRegex(FileExistsError, re.escape(msg)):
                 turtle.TurtleScreen.save(screen, file_path)