Issue #28353: os.fwalk() no longer fails on broken links.

Lib/os.py

@@ -537,13 +537,13 @@ if {open, stat} <= supports_dir_fd and {listdir, stat} <= supports_fd:
                     dirs.append(name)
                 else:
                     nondirs.append(name)
-            except FileNotFoundError:
+            except OSError:
                 try:
                     # Add dangling symlinks, ignore disappeared files
                     if st.S_ISLNK(stat(name, dir_fd=topfd, follow_symlinks=False)
                                 .st_mode):
                         nondirs.append(name)
-                except FileNotFoundError:
+                except OSError:
                     continue
 
         if topdown:

Lib/test/test_os.py

@@ -830,39 +830,53 @@ class WalkTests(unittest.TestCase):
         #           SUB11/          no kids
         #         SUB2/             a file kid and a dirsymlink kid
         #           tmp3
+        #           SUB21/          not readable
+        #             tmp5
         #           link/           a symlink to TESTFN.2
         #           broken_link
+        #           broken_link2
+        #           broken_link3
         #       TEST2/
         #         tmp4              a lone file
         self.walk_path = join(support.TESTFN, "TEST1")
         self.sub1_path = join(self.walk_path, "SUB1")
         self.sub11_path = join(self.sub1_path, "SUB11")
         sub2_path = join(self.walk_path, "SUB2")
+        self.sub21_path = join(sub2_path, "SUB21")
         tmp1_path = join(self.walk_path, "tmp1")
         tmp2_path = join(self.sub1_path, "tmp2")
         tmp3_path = join(sub2_path, "tmp3")
+        tmp5_path = join(self.sub21_path, "tmp3")
         self.link_path = join(sub2_path, "link")
         t2_path = join(support.TESTFN, "TEST2")
         tmp4_path = join(support.TESTFN, "TEST2", "tmp4")
         broken_link_path = join(sub2_path, "broken_link")
+        broken_link2_path = join(sub2_path, "broken_link2")
+        broken_link3_path = join(sub2_path, "broken_link3")
 
         # Create stuff.
         os.makedirs(self.sub11_path)
         os.makedirs(sub2_path)
+        os.makedirs(self.sub21_path)
         os.makedirs(t2_path)
 
-        for path in tmp1_path, tmp2_path, tmp3_path, tmp4_path:
-            f = open(path, "w")
-            f.write("I'm " + path + " and proud of it.  Blame test_os.\n")
-            f.close()
+        for path in tmp1_path, tmp2_path, tmp3_path, tmp4_path, tmp5_path:
+            with open(path, "x") as f:
+                f.write("I'm " + path + " and proud of it.  Blame test_os.\n")
 
         if support.can_symlink():
             os.symlink(os.path.abspath(t2_path), self.link_path)
             os.symlink('broken', broken_link_path, True)
-            self.sub2_tree = (sub2_path, ["link"], ["broken_link", "tmp3"])
+            os.symlink(join('tmp3', 'broken'), broken_link2_path, True)
+            os.symlink(join('SUB21', 'tmp5'), broken_link3_path, True)
+            self.sub2_tree = (sub2_path, ["link", "SUB21"],
+                              ["broken_link", "broken_link2", "broken_link3",
+                               "tmp3"])
         else:
             self.sub2_tree = (sub2_path, [], ["tmp3"])
 
+        os.chmod(self.sub21_path, 0)
+
     def test_walk_topdown(self):
         # Walk top-down.
         all = list(self.walk(self.walk_path))
@@ -935,6 +949,7 @@ class WalkTests(unittest.TestCase):
         # Windows, which doesn't have a recursive delete command.  The
         # (not so) subtlety is that rmdir will fail unless the dir's
         # kids are removed first, so bottom up is essential.
+        os.chmod(self.sub21_path, stat.S_IRWXU)
         for root, dirs, files in os.walk(support.TESTFN, topdown=False):
             for name in files:
                 os.remove(os.path.join(root, name))
@@ -1030,6 +1045,7 @@ class FwalkTests(WalkTests):
 
     def tearDown(self):
         # cleanup
+        os.chmod(self.sub21_path, stat.S_IRWXU)
         for root, dirs, files, rootfd in os.fwalk(support.TESTFN, topdown=False):
             for name in files:
                 os.unlink(name, dir_fd=rootfd)

Misc/NEWS

@@ -113,6 +113,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #28353: os.fwalk() no longer fails on broken links.
+
 - Issue #25464: Fixed HList.header_exists() in tkinter.tix module by addin
   a workaround to Tix library bug.