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.
$ hg init repo
$ cd repo
$ echo a > a
$ hg ci -Am0
adding a
$ hg -q clone . foo
$ touch .hg/store/journal
$ echo foo > a
$ hg ci -Am0
abort: abandoned transaction found
(run 'hg recover' to clean up transaction)
[255]
$ hg recover
rolling back interrupted transaction
(verify step skipped, run `hg verify` to check your repository content)
recover, explicit verify
$ touch .hg/store/journal
$ hg ci -Am0
abort: abandoned transaction found
(run 'hg recover' to clean up transaction)
[255]
$ hg recover --verify -q
recover, no verify
$ touch .hg/store/journal
$ hg ci -Am0
abort: abandoned transaction found
(run 'hg recover' to clean up transaction)
[255]
$ hg recover --no-verify
rolling back interrupted transaction
(verify step skipped, run `hg verify` to check your repository content)
Check that zero-size journals are correctly aborted:
#if unix-permissions no-root
$ hg bundle -qa repo.hg
$ chmod -w foo/.hg/store/00changelog.i
$ hg -R foo unbundle repo.hg
adding changesets
transaction abort!
rollback completed
abort: $EACCES$: '$TESTTMP/repo/foo/.hg/store/.00changelog.i-*' (glob)
[255]
$ if test -f foo/.hg/store/journal; then echo 'journal exists :-('; fi
#endif