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.
#testcases dirstate-v1 dirstate-v2
#if dirstate-v2
$ cat >> $HGRCPATH << EOF
> [format]
> use-dirstate-v2=1
> [storage]
> dirstate-v2.slow-path=allow
> EOF
#endif
The proliferation of status implementations can be confusing:
- The pure python implementation:
(no-rhg pure !)
- The C implementation:
(no-rhg no-rust no-pure !)
- The two rust implementations:
(rhg !)
(no-rhg rust !)
$ hg init repo1
$ cd repo1
$ mkdir d1
$ touch d1/x
$ hg commit -Am.
adding d1/x
$ touch d1/y
$ chmod -r d1
$ hg status
d1: $EACCES$
! d1/x (rhg !)
! d1/x (no-rhg rust !)
$ hg status
d1: $EACCES$
! d1/x (rust !)
! d1/x (no-rust rhg !)
$ chmod +r d1
$ hg status
? d1/y
$ touch d1/z
$ hg status
? d1/y
? d1/z