branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
$ cat >> $HGRCPATH << EOF
> [extensions]
> absorb=
> EOF
$ hg init repo1
$ cd repo1
Make some commits:
$ for i in 1 2 3; do
> echo $i >> a
> hg commit -A a -m "commit $i" -q
> done
absorb --edit-lines will run the editor if filename is provided:
$ hg absorb --edit-lines
nothing applied
[1]
$ HGEDITOR=cat hg absorb --edit-lines a
HG: editing a
HG: "y" means the line to the right exists in the changeset to the top
HG:
HG: /---- 4ec16f85269a commit 1
HG: |/--- 5c5f95224a50 commit 2
HG: ||/-- 43f0a75bede7 commit 3
HG: |||
yyy : 1
yy : 2
y : 3
nothing applied
[1]
Edit the file using --edit-lines:
$ cat > editortext << EOF
> y : a
> yy : b
> y : c
> yy : d
> y y : e
> y : f
> yyy : g
> EOF
$ HGEDITOR='cat editortext >' hg absorb -q --edit-lines a
$ hg cat -r 0 a
d
e
f
g
$ hg cat -r 1 a
b
c
d
g
$ hg cat -r 2 a
a
b
e
g