changegroup: pass version into constructor

Currently, the version is an attribute on each class. Passing
the argument into the constructor gets us one step closer to
eliminating cg2packer and cg3packer.

Differential Revision: https://phab.mercurial-scm.org/D4077

mercurial/changegroup.py

@@ -521,8 +521,8 b' class revisiondelta(object):'
 
 class cg1packer(object):
     deltaheader = _CHANGEGROUPV1_DELTA_HEADER
-    version = '01'
-    def __init__(self, repo, filematcher, bundlecaps=None):
+
+    def __init__(self, repo, filematcher, version, bundlecaps=None):
         """Given a source repo, construct a bundler.
 
         filematcher is a matcher that matches on files to include in the
@@ -536,6 +536,8 b' class cg1packer(object):'
         assert filematcher
         self._filematcher = filematcher
 
+        self.version = version
+
         # Set of capabilities we can use to build the bundle.
         if bundlecaps is None:
             bundlecaps = set()
@@ -1100,11 +1102,10 b' class cg1packer(object):'
         return struct.pack(self.deltaheader, node, p1n, p2n, linknode)
 
 class cg2packer(cg1packer):
-    version = '02'
     deltaheader = _CHANGEGROUPV2_DELTA_HEADER
 
-    def __init__(self, repo, filematcher, bundlecaps=None):
-        super(cg2packer, self).__init__(repo, filematcher,
+    def __init__(self, repo, filematcher, version, bundlecaps=None):
+        super(cg2packer, self).__init__(repo, filematcher, version,
                                         bundlecaps=bundlecaps)
 
         if self._reorder is None:
@@ -1157,7 +1158,6 b' class cg2packer(cg1packer):'
         return struct.pack(self.deltaheader, node, p1n, p2n, basenode, linknode)
 
 class cg3packer(cg2packer):
-    version = '03'
     deltaheader = _CHANGEGROUPV3_DELTA_HEADER
 
     def _packmanifests(self, dir, mfnodes, lookuplinknode):
@@ -1177,13 +1177,13 b' class cg3packer(cg2packer):'
             self.deltaheader, node, p1n, p2n, basenode, linknode, flags)
 
 def _makecg1packer(repo, filematcher, bundlecaps):
-    return cg1packer(repo, filematcher, bundlecaps=bundlecaps)
+    return cg1packer(repo, filematcher, b'01', bundlecaps=bundlecaps)
 
 def _makecg2packer(repo, filematcher, bundlecaps):
-    return cg2packer(repo, filematcher, bundlecaps=bundlecaps)
+    return cg2packer(repo, filematcher, b'02', bundlecaps=bundlecaps)
 
 def _makecg3packer(repo, filematcher, bundlecaps):
-    return cg3packer(repo, filematcher, bundlecaps=bundlecaps)
+    return cg3packer(repo, filematcher, b'03', bundlecaps=bundlecaps)
 
 _packermap = {'01': (_makecg1packer, cg1unpacker),
              # cg2 adds support for exchanging generaldelta