[PATCH 1 of 2 censor RFC v2] changegroup: clean up misnamed local variable in delta generation logic

[Mike Edgar]

# HG changeset patch
# User Mike Edgar <adgar at google.com>
# Date 1424465057 18000
#      Fri Feb 20 15:44:17 2015 -0500
# Node ID 96a3db818b2ec56f420c677ca38ea34dc46af9ff
# Parent  75f94dcf76fdfeaebeaaea279ca5b88e3bc8a20b
changegroup: clean up misnamed local variable in delta generation logic

The actual changegroup delta that is produced is sometimes split across two
variables, "prefix" and "delta"; othertimes, it is wholly contained in
"delta". This is confusing and inhibits extension of this logic.

diff -r 75f94dcf76fd -r 96a3db818b2e mercurial/changegroup.py
--- a/mercurial/changegroup.py	Thu Feb 19 19:32:06 2015 +0800
+++ b/mercurial/changegroup.py	Fri Feb 20 15:44:17 2015 -0500
@@ -480,16 +480,14 @@
         p1, p2 = revlog.parentrevs(rev)
         base = self.deltaparent(revlog, rev, p1, p2, prev)
 
-        prefix = ''
         if base == nullrev:
-            delta = revlog.revision(node)
-            prefix = mdiff.trivialdiffheader(len(delta))
+            snapshot = revlog.revision(node)
+            delta = mdiff.trivialdiffheader(len(snapshot)) + snapshot
         else:
             delta = revlog.revdiff(base, rev)
         p1n, p2n = revlog.parents(node)
         basenode = revlog.node(base)
         meta = self.builddeltaheader(node, p1n, p2n, basenode, linknode)
-        meta += prefix
         l = len(meta) + len(delta)
         yield chunkheader(l)
         yield meta