Add missing follow_symlink argument to os.link

- fixes pytest-dev#973

CHANGES.md

@@ -21,6 +21,7 @@ The released versions correspond to PyPI releases.
 * fixed creation of the temp directory in the fake file system after a filesystem reset
   (see [#965](../../issues/965))
 * fixed handling of `dirfd` in `os.symlink` (see [#968](../../issues/968))
+* add missing `follow_symlink` argument to `os.link` (see [#973](../../issues/973))
 
 ## [Version 5.3.5](https://pypi.python.org/pypi/pyfakefs/5.3.5) (2024-01-30)
 Fixes a regression.

pyfakefs/fake_os.py

@@ -1185,6 +1185,7 @@ def link(
         *,
         src_dir_fd: Optional[int] = None,
         dst_dir_fd: Optional[int] = None,
+        follow_symlinks: Optional[bool] = None,
     ) -> None:
         """Create a hard link at dst, pointing at src.
 
@@ -1195,14 +1196,21 @@ def link(
                 with `src` being relative to this directory.
             dst_dir_fd: If not `None`, the file descriptor of a directory,
                 with `dst` being relative to this directory.
+            follow_symlinks: (bool) If True (the default), symlinks in the
+                path are traversed.
 
         Raises:
             OSError:  if something already exists at new_path.
             OSError:  if the parent directory doesn't exist.
         """
+        if IS_PYPY and follow_symlinks is not None:
+            raise OSError(errno.EINVAL, "Invalid argument: follow_symlinks")
+        if follow_symlinks is None:
+            follow_symlinks = True
+
         src = self._path_with_dir_fd(src, self.link, src_dir_fd)
         dst = self._path_with_dir_fd(dst, self.link, dst_dir_fd)
-        self.filesystem.link(src, dst)
+        self.filesystem.link(src, dst, follow_symlinks=follow_symlinks)
 
     def fsync(self, fd: int) -> None:
         """Perform fsync for a fake file (in other words, do nothing).

pyfakefs/tests/fake_os_test.py

@@ -2705,6 +2705,29 @@ def test_link_count1(self):
         self.os.unlink(file1_path)
         self.assertEqual(self.os.stat(file2_path).st_nlink, 1)
 
+    @unittest.skipIf(IS_PYPY, "follow_symlinks not supported in PyPi")
+    def test_link_no_follow_symlink(self):
+        self.skip_if_symlink_not_supported()
+        target_path = self.make_path("target_path")
+        self.create_file(target_path, contents="foo")
+        symlink_path = self.make_path("symlink_to_file")
+        self.create_symlink(symlink_path, target_path)
+        link_path = self.make_path("link_to_symlink")
+        self.os.link(symlink_path, link_path, follow_symlinks=False)
+        self.assertTrue(self.os.path.islink(link_path))
+
+    @unittest.skipIf(not IS_PYPY, "follow_symlinks only not supported in PyPi")
+    def test_link_follow_symlink_not_supported_inPypy(self):
+        self.skip_if_symlink_not_supported()
+        target_path = self.make_path("target_path")
+        self.create_file(target_path, contents="foo")
+        symlink_path = self.make_path("symlink_to_file")
+        self.create_symlink(symlink_path, target_path)
+        link_path = self.make_path("link_to_symlink")
+        with self.assertRaises(OSError) as cm:
+            self.os.link(symlink_path, link_path, follow_symlinks=False)
+        self.assertEqual(errno.EINVAL, cm.exception.errno)
+
     def test_nlink_for_directories(self):
         self.skip_real_fs()
         self.create_dir(self.make_path("foo", "bar"))