Bug #1048941: shutil.rmtree error handling was always broken

Rewrite rmtree again, this time without os.walk(). Error handling had been
broken since Python 2.3, and the os.walk() version inherited this.

Lib/shutil.py

@@ -127,39 +127,45 @@ def copytree(src, dst, symlinks=False):
     if errors:
         raise Error, errors
 
-def _raise_err(err):
-    raise err
-
 def rmtree(path, ignore_errors=False, onerror=None):
     """Recursively delete a directory tree.
 
-    If ignore_errors is set, errors are ignored; otherwise, if
-    onerror is set, it is called to handle the error; otherwise, an
-    exception is raised.
+    If ignore_errors is set, errors are ignored; otherwise, if onerror
+    is set, it is called to handle the error with arguments (func,
+    path, exc_info) where func is os.listdir, os.remove, or os.rmdir;
+    path is the argument to that function that caused it to fail; and
+    exc_info is a tuple returned by sys.exc_info().  If ignore_errors
+    is false and onerror is None, an exception is raised.
+
     """
-    # This strange way of calling functions is necessary to keep the onerror
-    # argument working. Maybe sys._getframe hackery would work as well, but
-    # this is simple.
-    func = os.listdir
-    arg = path
-    try:
-        for (dirpath, dirnames, filenames) in os.walk(path, topdown=False,
-                                                      onerror=_raise_err):
-            for filename in filenames:
-                func = os.remove
-                arg = os.path.join(dirpath, filename)
-                func(arg)
-            func = os.rmdir
-            arg = dirpath
-            func(arg)
-    except OSError:
-        exc = sys.exc_info()
-        if ignore_errors:
+    if ignore_errors:
+        def onerror(*args):
             pass
-        elif onerror is not None:
-            onerror(func, arg, exc)
+    elif onerror is None:
+        def onerror(*args):
+            raise
+    names = []
+    try:
+        names = os.listdir(path)
+    except os.error, err:
+        onerror(os.listdir, path, sys.exc_info())
+    for name in names:
+        fullname = os.path.join(path, name)
+        try:
+            mode = os.lstat(fullname).st_mode
+        except os.error:
+            mode = 0
+        if stat.S_ISDIR(mode):
+            rmtree(fullname, ignore_errors, onerror)
         else:
-            raise exc[0], (exc[1][0], exc[1][1] + ' removing '+arg)
+            try:
+                os.remove(fullname)
+            except os.error, err:
+                onerror(os.remove, fullname, sys.exc_info())
+    try:
+        os.rmdir(path)
+    except os.error:
+        onerror(os.rmdir, path, sys.exc_info())
 
 def move(src, dst):
     """Recursively move a file or directory to another location.

Lib/test/test_shutil.py

@@ -1,8 +1,10 @@
+
 # Copyright (C) 2003 Python Software Foundation
 
 import unittest
 import shutil
 import tempfile
+import stat
 import os
 import os.path
 from test import test_support
@@ -13,8 +15,32 @@ class TestShutil(unittest.TestCase):
         # filename is guaranteed not to exist
         filename = tempfile.mktemp()
         self.assertRaises(OSError, shutil.rmtree, filename)
-        self.assertEqual(shutil.rmtree(filename, True), None)
-        shutil.rmtree(filename, False, lambda func, arg, exc: None)
+
+    if hasattr(os, 'chmod'):
+        def test_on_error(self):
+            self.errorState = 0
+            os.mkdir(TESTFN)
+            f = open(os.path.join(TESTFN, 'a'), 'w')
+            f.close()
+            # Make TESTFN unwritable.
+            os.chmod(TESTFN, stat.S_IRUSR)
+
+            shutil.rmtree(TESTFN, onerror=self.check_args_to_onerror)
+
+            # Make TESTFN writable again.
+            os.chmod(TESTFN, stat.S_IRWXU)
+            shutil.rmtree(TESTFN)
+
+    def check_args_to_onerror(self, func, arg, exc):
+        if self.errorState == 0:
+            self.assertEqual(func, os.remove)
+            self.assertEqual(arg, os.path.join(TESTFN, 'a'))
+            self.assertEqual(exc[0], OSError)
+            self.errorState = 1
+        else:
+            self.assertEqual(func, os.rmdir)
+            self.assertEqual(arg, TESTFN)
+            self.assertEqual(exc[0], OSError)
 
     def test_rmtree_dont_delete_file(self):
         # When called on a file instead of a directory, don't delete it.
@@ -63,7 +89,6 @@ class TestShutil(unittest.TestCase):
                 except OSError:
                     pass
 
-
 def test_main():
     test_support.run_unittest(TestShutil)