revset: define successors revset
This revset returns all successors, including transit nodes and the source
nodes (to be consistent with existing revsets like "ancestors").
To filter out transit nodes, use `successors(X)-obsolete()`.
To filter out divergent case, use `successors(X)-divergent()-obsolete()`.
The revset could be useful to define rebase destination, like:
`max(successors(BASE)-divergent()-obsolete())`. The `max` is to deal with
splits.
There are other implementations where `successors` returns just one level of
successors, and `allsuccessors` returns everything. I think `successors`
returning all successors by default is more user friendly. We have seen
cases in production where people use 1-level `successors` while they really
want `allsuccessors`. So it seems better to just have one single revset
returning all successors by default to avoid user errors.
In the future we might want to add `depth` keyword argument to it and for
other revsets like `ancestors` etc. Or even build some flexible indexing
syntax [1] to satisfy people having the depth limit requirement.
[1]: https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-July/101140.html
Enable obsolete markers
$ cat >> $HGRCPATH << EOF
> [experimental]
> evolution=createmarkers
> [phases]
> publish=False
> EOF
Build a repo with some cacheable bits:
$ hg init a
$ cd a
$ echo a > a
$ hg ci -qAm0
$ hg tag t1
$ hg book -i bk1
$ hg branch -q b2
$ hg ci -Am1
$ hg tag t2
$ echo dumb > dumb
$ hg ci -qAmdumb
$ hg debugobsolete b1174d11b69e63cb0c5726621a43c859f0858d7f
$ hg phase -pr t1
$ hg phase -fsr t2
Make a helper function to check cache damage invariants:
- command output shouldn't change
- cache should be present after first use
- corruption/repair should be silent (no exceptions or warnings)
- cache should survive deletion, overwrite, and append
- unreadable / unwriteable caches should be ignored
- cache should be rebuilt after corruption
$ damage() {
> CMD=$1
> CACHE=.hg/cache/$2
> CLEAN=$3
> hg $CMD > before
> test -f $CACHE || echo "not present"
> echo bad > $CACHE
> test -z "$CLEAN" || $CLEAN
> hg $CMD > after
> diff -u before after || echo "*** overwrite corruption"
> echo corruption >> $CACHE
> test -z "$CLEAN" || $CLEAN
> hg $CMD > after
> diff -u before after || echo "*** append corruption"
> rm $CACHE
> mkdir $CACHE
> test -z "$CLEAN" || $CLEAN
> hg $CMD > after
> diff -u before after || echo "*** read-only corruption"
> test -d $CACHE || echo "*** directory clobbered"
> rmdir $CACHE
> test -z "$CLEAN" || $CLEAN
> hg $CMD > after
> diff -u before after || echo "*** missing corruption"
> test -f $CACHE || echo "not rebuilt"
> }
Beat up tags caches:
$ damage "tags --hidden" tags2
$ damage tags tags2-visible
$ damage "tag -f t3" hgtagsfnodes1
Beat up branch caches:
$ damage branches branch2-base "rm .hg/cache/branch2-[vs]*"
$ damage branches branch2-served "rm .hg/cache/branch2-[bv]*"
$ damage branches branch2-visible
$ damage "log -r branch(.)" rbc-names-v1
$ damage "log -r branch(default)" rbc-names-v1
$ damage "log -r branch(b2)" rbc-revs-v1
We currently can't detect an rbc cache with unknown names:
$ damage "log -qr branch(b2)" rbc-names-v1
--- before * (glob)
+++ after * (glob)
@@ -1,8 +?,0 @@ (glob)
-2:5fb7d38b9dc4
-3:60b597ffdafa
-4:b1174d11b69e
-5:6354685872c0
-6:5ebc725f1bef
-7:7b76eec2f273
-8:ef3428d9d644
-9:ba7a936bc03c
*** append corruption