branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
$ 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