[PATCH stable] convert.cvs: Initialize state variable and abort on cvs error

[Mads Kiilerich]

# HG changeset patch
# User Mads Kiilerich <mads at kiilerich.com>
# Date 1269909741 -7200
# Branch stable
# Node ID 2837acc6e4fe44ca9584737e1a51e2fcd5b2c27e
# Parent  4cee900210bcaa2b0cdc2c2fca999274e2ee7e49
convert.cvs: Initialize state variable and abort on cvs error

Fix as proposed by Frank Kingswood.

Avoids
UnboundLocalError: local variable 'mode' referenced before assignment
when cvs fails.

This alsa partially fixes issue1592.

diff --git a/hgext/convert/cvs.py b/hgext/convert/cvs.py
--- a/hgext/convert/cvs.py
+++ b/hgext/convert/cvs.py
@@ -227,6 +227,7 @@
         self.writep.flush()
 
         data = ""
+        mode = None
         while 1:
             line = self.readp.readline()
             if line.startswith("Created ") or line.startswith("Updated "):
@@ -244,6 +245,8 @@
                 data = chunkedread(self.readp, count)
             else:
                 if line == "ok\n":
+                    if mode is None:
+                        raise util.Abort(_('malformed response from CVS'))
                     return (data, "x" in mode and "x" or "")
                 elif line.startswith("E "):
                     self.ui.warn(_("cvs server: %s\n") % line[2:])