sqlitestore: support for storing revisions without their parents
This commit kinda/sorta implements the equivalent of ellipsis nodes for
the SQLite storage backend.
Without implementing full blown ellipsis nodes (and the necessary support for
them in the wire protocol), we instead teach the store to rewrite the p1 and
p2 nodes to nullid when the incoming parent isn't in the local store. This allows
servers to remain dumb and send the real parent and have the clients deal
with the missing parent problem.
This obviously isn't ideal because a benefit of ellipsis nodes is we can
insert a fake parent to ellide missing changesets. But neither solution is
ideal because it drops the original parent from storage. We could probably
teach the SQLite store to retain the original parent and handle missing
parents at read time. However, parent revisions are stored as integers and
it isn't trivial to store an "empty" revision in the store yet, which would
be necessary to represent the "missing" parent.
The store is somewhat intelligent in trying to remove the missing parents
metadata when the revision is re-added. But, revision numbers will be all
messed up in that case, so I'm not sure it is worth it. At some point we'll
likely want to remove the concept of revision numbers from the database and
have the store invent them at index generation time. Or even better, we can
do away with revision numbers from the file storage interface completely.
We'll get there eventually...
Differential Revision: https://phab.mercurial-scm.org/D5168
$ cat >> $HGRCPATH << EOF
> [extensions]
> blackbox=
> rebase=
> mock=$TESTDIR/mockblackbox.py
>
> [experimental]
> evolution.createmarkers=True
> EOF
Create a repo with some tags
$ hg init repo
$ cd repo
$ echo initial > foo
$ hg -q commit -A -m initial
$ hg tag -m 'test tag' test1
$ echo first > first
$ hg -q commit -A -m first
$ hg tag -m 'test2 tag' test2
$ hg -q up -r 0
$ echo newhead > newhead
$ hg commit -A -m newhead
adding newhead
created new head
$ hg tag -m 'test head 2 tag' head2
$ hg log -G -T '{rev}:{node|short} {tags} {desc}\n'
@ 5:2942a772f72a tip test head 2 tag
|
o 4:042eb6bfcc49 head2 newhead
|
| o 3:c3cb30f2d2cd test2 tag
| |
| o 2:d75775ffbc6b test2 first
| |
| o 1:5f97d42da03f test tag
|/
o 0:55482a6fb4b1 test1 initial
Trigger tags cache population by doing something that accesses tags info
$ hg tags
tip 5:2942a772f72a
head2 4:042eb6bfcc49
test2 2:d75775ffbc6b
test1 0:55482a6fb4b1
$ cat .hg/cache/tags2-visible
5 2942a772f72a444bef4bef13874d515f50fa27b6
042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
55482a6fb4b1881fa8f746fd52cf6f096bb21c89 test1
d75775ffbc6bca1794d300f5571272879bd280da test2
Hiding a non-tip changeset should change filtered hash and cause tags recompute
$ hg debugobsolete -d '0 0' c3cb30f2d2cd0aae008cc91a07876e3c5131fd22 -u dummyuser
obsoleted 1 changesets
$ hg tags
tip 5:2942a772f72a
head2 4:042eb6bfcc49
test1 0:55482a6fb4b1
$ cat .hg/cache/tags2-visible
5 2942a772f72a444bef4bef13874d515f50fa27b6 f34fbc9a9769ba9eff5aff3d008a6b49f85c08b1
042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
55482a6fb4b1881fa8f746fd52cf6f096bb21c89 test1
$ hg blackbox -l 5
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> tags
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> 2/2 cache hits/lookups in * seconds (glob)
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> writing .hg/cache/tags2-visible with 2 tags
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> tags exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> blackbox -l 5
Hiding another changeset should cause the filtered hash to change
$ hg debugobsolete -d '0 0' d75775ffbc6bca1794d300f5571272879bd280da -u dummyuser
obsoleted 1 changesets
$ hg debugobsolete -d '0 0' 5f97d42da03fd56f3b228b03dfe48af5c0adf75b -u dummyuser
obsoleted 1 changesets
$ hg tags
tip 5:2942a772f72a
head2 4:042eb6bfcc49
$ cat .hg/cache/tags2-visible
5 2942a772f72a444bef4bef13874d515f50fa27b6 2fce1eec33263d08a4d04293960fc73a555230e4
042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
$ hg blackbox -l 5
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> tags
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> 1/1 cache hits/lookups in * seconds (glob)
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> writing .hg/cache/tags2-visible with 1 tags
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> tags exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> blackbox -l 5
Resolving tags on an unfiltered repo writes a separate tags cache
$ hg --hidden tags
tip 5:2942a772f72a
head2 4:042eb6bfcc49
test2 2:d75775ffbc6b
test1 0:55482a6fb4b1
$ cat .hg/cache/tags2
5 2942a772f72a444bef4bef13874d515f50fa27b6
042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
55482a6fb4b1881fa8f746fd52cf6f096bb21c89 test1
d75775ffbc6bca1794d300f5571272879bd280da test2
$ hg blackbox -l 5
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> --hidden tags
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> 2/2 cache hits/lookups in * seconds (glob)
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> writing .hg/cache/tags2 with 3 tags
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> --hidden tags exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> blackbox -l 5