Fail renaming a file to or from a path with a trailing separator

CHANGES.md

@@ -23,6 +23,8 @@ The released versions correspond to PyPI releases.
 * fixed `os.rename` failing for the root user in a directory owned by
   another user
   (see [#1341](https://github.com/pytest-dev/pyfakefs/issues/1341))
+* fixed `os.rename` and `os.replace` succeeding under Posix when renaming
+  a file to a path with a trailing separator, or from `file/`
 
 ## [Version 6.2.0](https://pypi.python.org/pypi/pyfakefs/6.2.0) (2026-04-12)
 

pyfakefs/fake_filesystem.py

@@ -2005,6 +2005,7 @@ def rename(
         old_path = make_string_path(old_file_path)
         new_path = make_string_path(new_file_path)
         ends_with_sep = self.ends_with_path_separator(old_path)
+        new_ends_with_sep = self.ends_with_path_separator(new_path)
         old_path = self.absnormpath(old_path)
         new_path = self.absnormpath(new_path)
         if not self.exists(old_path, check_link=True):
@@ -2013,6 +2014,10 @@ def rename(
             self._handle_broken_link_with_trailing_sep(old_path)
 
         old_object = self.lresolve(old_path)
+        if not self.is_windows_fs and not S_ISDIR(old_object.st_mode):
+            self._handle_posix_non_dir_with_trailing_sep(
+                old_path, new_path, old_object, ends_with_sep, new_ends_with_sep
+            )
         if not self.is_windows_fs:
             self._handle_posix_dir_link_errors(new_path, old_path, ends_with_sep)
 
@@ -2066,6 +2071,27 @@ def _do_rename(self, old_dir_object, old_name, new_dir_object, new_name):
             old_dir_object.add_entry(object_to_rename)
             raise
 
+    def _handle_posix_non_dir_with_trailing_sep(
+        self,
+        old_path: AnyStr,
+        new_path: AnyStr,
+        old_object: AnyFile,
+        old_ends_with_sep: bool,
+        new_ends_with_sep: bool,
+    ) -> None:
+        # a trailing separator requires a directory, so renaming a file
+        # (or a symlink) from or to such a path fails
+        if old_ends_with_sep and S_ISREG(old_object.st_mode):
+            self.raise_os_error(errno.ENOTDIR, old_path)
+        if new_ends_with_sep and self.exists(self.splitpath(new_path)[0]):
+            error = errno.ENOTDIR
+            if self.is_macos:
+                if not self.exists(new_path):
+                    error = errno.ENOENT
+                elif self.isdir(new_path):
+                    error = errno.EISDIR
+            self.raise_os_error(error, new_path)
+
     def _handle_broken_link_with_trailing_sep(self, path: AnyStr) -> None:
         # note that the check for trailing sep has to be done earlier
         if self.islink(path) and not self.exists(path):

pyfakefs/tests/fake_os_test.py

@@ -2608,6 +2608,41 @@ def test_rename_to_path_ending_with_sep(self):
                 errno.ENOTDIR, self.os.rename, file_path + self.os.sep, file_path
             )
 
+    def check_rename_file_to_path_ending_with_sep(self, errors):
+        file_path = self.make_path("foo")
+        self.create_file(file_path)
+        self.create_dir(self.make_path("dir"))
+        for name, error in zip(("bar", "foo", "dir"), errors):
+            new_path = self.make_path(name) + self.os.sep
+            self.assert_raises_os_error(error, self.os.rename, file_path, new_path)
+            self.assert_raises_os_error(error, self.os.replace, file_path, new_path)
+        self.assertTrue(self.os.path.isfile(file_path))
+        self.assertFalse(self.os.path.exists(self.make_path("bar")))
+
+    def test_rename_file_to_path_ending_with_sep_linux(self):
+        self.check_linux_only()
+        self.check_rename_file_to_path_ending_with_sep(
+            (errno.ENOTDIR, errno.ENOTDIR, errno.ENOTDIR)
+        )
+
+    def test_rename_file_to_path_ending_with_sep_macos(self):
+        self.check_macos_only()
+        self.check_rename_file_to_path_ending_with_sep(
+            (errno.ENOENT, errno.ENOTDIR, errno.EISDIR)
+        )
+
+    def test_rename_file_with_trailing_sep_posix(self):
+        self.check_posix_only()
+        file_path = self.make_path("foo")
+        self.create_file(file_path)
+        self.assert_raises_os_error(
+            errno.ENOTDIR,
+            self.os.rename,
+            file_path + self.os.sep,
+            self.make_path("bar"),
+        )
+        self.assertTrue(self.os.path.isfile(file_path))
+
     def test_rmdir_link_with_trailing_sep_linux(self):
         self.check_linux_only()
         dir_path = self.make_path("foo")