phases: change phase command change detection
A future patch is going to make phase computation lazy, so the phase command can
no longer read and diff the entire phase list directly. This changes the phase
command to build it's own list for diff purposes.
$ cat > engine.py << EOF
>
> from mercurial import templater
>
> class mytemplater(object):
> def __init__(self, loader, filters, defaults):
> self.loader = loader
>
> def process(self, t, map):
> tmpl = self.loader(t)
> for k, v in map.iteritems():
> if k in ('templ', 'ctx', 'repo', 'revcache', 'cache'):
> continue
> if hasattr(v, '__call__'):
> v = v(**map)
> v = templater.stringify(v)
> tmpl = tmpl.replace('{{%s}}' % k, v)
> yield tmpl
>
> templater.engines['my'] = mytemplater
> EOF
$ hg init test
$ echo '[extensions]' > test/.hg/hgrc
$ echo "engine = `pwd`/engine.py" >> test/.hg/hgrc
$ cd test
$ cat > mymap << EOF
> changeset = my:changeset.txt
> EOF
$ cat > changeset.txt << EOF
> {{rev}} {{node}} {{author}}
> EOF
$ hg ci -Ama
adding changeset.txt
adding mymap
$ hg log --style=./mymap
0 97e5f848f0936960273bbf75be6388cd0350a32b test
$ cat > changeset.txt << EOF
> {{p1rev}} {{p1node}} {{p2rev}} {{p2node}}
> EOF
$ hg ci -Ama
$ hg log --style=./mymap
0 97e5f848f0936960273bbf75be6388cd0350a32b -1 0000000000000000000000000000000000000000
-1 0000000000000000000000000000000000000000 -1 0000000000000000000000000000000000000000
$ cd ..