bookmarks: allow pushkey if new equals current
Previously a bookmark pushkey would be rejected if the specified 'old' value
didn't match the servers 'current' value. This change allows this situation, as
long as the 'current' server value equals the 'new' pushkey value already.
We are trying to write a hook that forces a server bookmark to move forward,
using a changegroup hook. If the user also pushed the bookmark, they would get
an error, since they computed their pushkey (old,new) pair before the server
moved the bookmark. Long term, bundle2 will let us do this more smartly, but
this change seems reasonable for now.
Minimal hgk check
$ echo "[extensions]" >> $HGRCPATH
$ echo "hgk=" >> $HGRCPATH
$ hg init repo
$ cd repo
$ echo a > a
$ hg ci -Am adda
adding a
$ hg debug-cat-file commit 0
tree a0c8bcbbb45c
parent 000000000000
author test 0 0
revision 0
branch default
phase draft
adda
$ cd ..