merge: cache unknown dir checks (
issue5716)
As mentioned in D1222, the recent pathconflicts change regresses update
performance in large repositories when many files are being updated.
To mitigate this, we introduce two caches of directories that have
already found to be either:
- unknown directories, but which are not aliased by files and
so don't need to be checked if they are files again; and
- missing directores, which cannot cause path conflicts, and
cannot contain a file that causes a path conflict.
When checking the paths of a file, testing against this caches means we can
skip tests that involve touching the filesystem.
Differential Revision: https://phab.mercurial-scm.org/D1224
$ hg init
$ 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
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
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
abort: Permission denied: $TESTTMP/foo/.hg/store/.00changelog.i-* (glob)
[255]
$ if test -f foo/.hg/store/journal; then echo 'journal exists :-('; fi
#endif