checkheads: extract bookmark computation from the branch loop
No branch specific data are used in the computation of the bookmarked heads. We
can only compute it once.
$ hg init
$ echo a > a
$ hg add a
$ hg commit -m test
Do we ever miss a sub-second change?:
$ for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20; do
> hg co -qC 0
> echo b > a
> hg st
> done
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a
M a