[PATCH] changelog: update read pending documentation

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at fb.com>
# Date 1437141236 -7200
#      Fri Jul 17 15:53:56 2015 +0200
# Node ID c2a8490bf431ffb808f3b3b80c5837f423865b63
# Parent  35fa7c77c754aa4d156c42abfdb61ca178468872
changelog: update read pending documentation

The pending index contains a full copy of the index + in-transaction data. We
replace "extend" with "overwrite" to make this clearer.

diff --git a/mercurial/changelog.py b/mercurial/changelog.py
--- a/mercurial/changelog.py
+++ b/mercurial/changelog.py
@@ -267,11 +267,11 @@ class changelog(revlog.revlog):
         is running, we are likely in a subprocess invoked in a hook. The
         subprocess is informed that it is within a transaction and needs to
         access its content.
 
         This function will read all the index data out of the pending file and
-        extend the main index."""
+        overwrite the main index."""
 
         if not self.opener.exists(file):
             return # no pending data for changelog
         r = revlog.revlog(self.opener, file)
         self.index = r.index