shortest: make pure code also disambigute against revnums at end
This makes the pure code more similar to the native code in that it
first finds a prefix that's unambiguous among nodeids and then adds
hex digits until it no longer looks like a revnum. It will allow us to
even better separate the disambiguation with revnums in a later patch.
With this patch `hg log -r 0::50 -T '{shortest(node,1)}'` with no
native code goes from 25s to 43s. It wasn't exactly usable to begin
with, so I don't feel too bad about it.
Differential Revision: https://phab.mercurial-scm.org/D3500
#!/bin/sh
#
# Use this script to generate empty.svndump
#
mkdir temp
cd temp
mkdir project-orig
cd project-orig
mkdir trunk
mkdir branches
mkdir tags
cd ..
svnadmin create svn-repo
svnurl=file://`pwd`/svn-repo
svn import project-orig $svnurl -m "init projA"
svn co $svnurl project
cd project
mkdir trunk/dir
echo a > trunk/dir/a
svn add trunk/dir
svn ci -m adddir
echo b > trunk/b
svn add trunk/b
svn ci -m addb
echo c > c
svn add c
svn ci -m addc
cd ..
# svnsync repo/trunk/dir only so the last two revisions are empty
svnadmin create svn-empty
cat > svn-empty/hooks/pre-revprop-change <<EOF
#!/bin/sh
exit 0
EOF
chmod +x svn-empty/hooks/pre-revprop-change
svnsync init --username svnsync file://`pwd`/svn-empty file://`pwd`/svn-repo/trunk/dir
svnsync sync file://`pwd`/svn-empty
svn log -v file://`pwd`/svn-empty
svnadmin dump svn-empty > ../empty.svndump