[Python-checkins] cpython (merge 3.3 -> default): Issue #16601: Restarting iteration over tarfile no more continues from where

[serhiy.storchaka]

http://hg.python.org/cpython/rev/1c6a1427353b
changeset:   83694:1c6a1427353b
parent:      83690:375d4fed4cf2
parent:      83693:9ed127d8ad61
user:        Serhiy Storchaka <storchaka at gmail.com>
date:        Thu May 09 14:36:58 2013 +0300
summary:
  Issue #16601: Restarting iteration over tarfile no more continues from where
it left off.  Patch by Michael Birtwell.

files:
  Lib/tarfile.py           |  12 +++++++-----
  Lib/test/test_tarfile.py |   8 ++++++++
  Misc/ACKS                |   1 +
  Misc/NEWS                |   3 +++
  4 files changed, 19 insertions(+), 5 deletions(-)


diff --git a/Lib/tarfile.py b/Lib/tarfile.py
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -2397,16 +2397,18 @@
         # Fix for SF #1100429: Under rare circumstances it can
         # happen that getmembers() is called during iteration,
         # which will cause TarIter to stop prematurely.
-        if not self.tarfile._loaded:
+
+        if self.index == 0 and self.tarfile.firstmember is not None:
+            tarinfo = self.tarfile.next()
+        elif self.index < len(self.tarfile.members):
+            tarinfo = self.tarfile.members[self.index]
+        elif not self.tarfile._loaded:
             tarinfo = self.tarfile.next()
             if not tarinfo:
                 self.tarfile._loaded = True
                 raise StopIteration
         else:
-            try:
-                tarinfo = self.tarfile.members[self.index]
-            except IndexError:
-                raise StopIteration
+            raise StopIteration
         self.index += 1
         return tarinfo
 
diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py
--- a/Lib/test/test_tarfile.py
+++ b/Lib/test/test_tarfile.py
@@ -415,6 +415,14 @@
         finally:
             support.unlink(empty)
 
+    def test_parallel_iteration(self):
+        # Issue #16601: Restarting iteration over tarfile continued
+        # from where it left off.
+        with tarfile.open(self.tarname) as tar:
+            for m1, m2 in zip(tar, tar):
+                self.assertEqual(m1.offset, m2.offset)
+                self.assertEqual(m1.get_info(), m2.get_info())
+
 
 class StreamReadTest(CommonReadTest):
 
diff --git a/Misc/ACKS b/Misc/ACKS
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -118,6 +118,7 @@
 David Binger
 Dominic Binks
 Philippe Biondi
+Michael Birtwell
 Stuart Bishop
 Roy Bixler
 Daniel Black
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -86,6 +86,9 @@
 Library
 -------
 
+- Issue #16601: Restarting iteration over tarfile no more continues from where
+  it left off.  Patch by Michael Birtwell.
+
 - Issue #17289: The readline module now plays nicer with external modules
   or applications changing the rl_completer_word_break_characters global
   variable.  Initial patch by Bradley Froehle.

-- 
Repository URL: http://hg.python.org/cpython