# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@fb.com>
# Date 2014-03-18 23:35:34
# Node ID 88db3e6153196e2731a71f0044223659edf63b7e
# Parent  520df53ad26a9105f5d4a7647243567bb7a0e697

bundle2: make sure the unbundler refuse non bundle2 stream

We now make use of the magic string at the beginning of the file.

diff --git a/mercurial/bundle2.py b/mercurial/bundle2.py
--- a/mercurial/bundle2.py
+++ b/mercurial/bundle2.py
@@ -62,7 +62,7 @@ Binary format is as follow
 
 import util
 import changegroup
-
+from i18n import _
 
 _magicstring = 'HG20'
 
@@ -93,10 +93,13 @@ class unbundle20(object):
     (this will eventually yield parts)"""
 
     def __init__(self, fp):
-        # assume the magic string is ok and drop it
-        # to be obviously fixed soon.
         self._fp = fp
-        self._readexact(4)
+        header = self._readexact(4)
+        magic, version = header[0:2], header[2:4]
+        if magic != 'HG':
+            raise util.Abort(_('not a Mercurial bundle'))
+        if version != '20':
+            raise util.Abort(_('unknown bundle version %s') % version)
 
     def _unpack(self, format):
         """unpack this struct format from the stream"""
diff --git a/tests/test-bundle2.t b/tests/test-bundle2.t
--- a/tests/test-bundle2.t
+++ b/tests/test-bundle2.t
@@ -38,6 +38,9 @@ The extension requires a repo (currently
 
   $ hg init main
   $ cd main
+  $ touch a
+  $ hg add a
+  $ hg commit -m 'a'
 
 Test simple generation of empty bundle
 
@@ -49,3 +52,11 @@ Test parsing of an empty bundle
   $ hg bundle2 | hg unbundle2
   options count: 0
   parts count:   0
+
+Test old style bundle are detected and refused
+
+  $ hg bundle --all ../bundle.hg
+  1 changesets found
+  $ hg unbundle2 < ../bundle.hg
+  abort: unknown bundle version 10
+  [255]