Change revlog.heads to walk the revision graph using revision numbers
On the kernel repo:
$ hg heads -q
before after
RevlogNG 1.11 0.52
Revlogv0 0.80 0.69
Since the current code for tags has to find all the heads of the repo,
this also helps there:
$ hg tags
before after
RevlogNG 2.35 1.76
Revlogv0 2.04 1.90
#!/bin/sh
hg init
hg log
hg grep wah
hg manifest
hg verify