Merged revisions 77895-77896 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k

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  r77895 | antoine.pitrou | 2010-01-31 23:47:27 +0100 (dim., 31 janv. 2010) | 12 lines

  Merged revisions 77890 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

  ........
    r77890 | antoine.pitrou | 2010-01-31 23:26:04 +0100 (dim., 31 janv. 2010) | 7 lines

    - Issue #6939: Fix file I/O objects in the `io` module to keep the original
      file position when calling `truncate()`.  It would previously change the
      file position to the given argument, which goes against the tradition of
      ftruncate() and other truncation APIs.  Patch by Pascal Chambon.
  ........
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  r77896 | antoine.pitrou | 2010-02-01 00:12:29 +0100 (lun., 01 févr. 2010) | 3 lines

  r77895 broke doctest.
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diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index 2458e40..a9ff985 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -851,7 +851,7 @@
         elif pos < 0:
             raise ValueError("negative truncate position %r" % (pos,))
         del self._buffer[pos:]
-        return self.seek(pos)
+        return pos
 
     def readable(self):
         return True
@@ -1210,8 +1210,7 @@
         if pos is None:
             pos = self.tell()
         # Use seek to flush the read buffer.
-        self.seek(pos)
-        return BufferedWriter.truncate(self)
+        return BufferedWriter.truncate(self, pos)
 
     def read(self, n=None):
         if n is None:
@@ -1712,8 +1711,7 @@
         self.flush()
         if pos is None:
             pos = self.tell()
-        self.seek(pos)
-        return self.buffer.truncate()
+        return self.buffer.truncate(pos)
 
     def detach(self):
         if self.buffer is None: