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
$ . "$TESTDIR/narrow-library.sh"
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [narrow]
> serveellipses=True
> EOF
$ for x in `$TESTDIR/seq.py 10`
> do
> echo $x > "f$x"
> hg add "f$x"
> hg commit -m "Commit f$x"
> done
$ cd ..
narrow clone a couple files, f2 and f8
$ hg clone --narrow ssh://user@dummy/master narrow --include "f2" --include "f8"
requesting all changes
adding changesets
adding manifests
adding file changes
added 5 changesets with 2 changes to 2 files
new changesets *:* (glob)
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd narrow
$ ls
f2
f8
$ cat f2 f8
2
8
$ cd ..
change every upstream file twice
$ cd master
$ for x in `$TESTDIR/seq.py 10`
> do
> echo "update#1 $x" >> "f$x"
> hg commit -m "Update#1 to f$x" "f$x"
> done
$ for x in `$TESTDIR/seq.py 10`
> do
> echo "update#2 $x" >> "f$x"
> hg commit -m "Update#2 to f$x" "f$x"
> done
$ cd ..
look for incoming changes
$ cd narrow
$ hg incoming --limit 3
comparing with ssh://user@dummy/master
searching for changes
changeset: 5:ddc055582556
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Update#1 to f1
changeset: 6:f66eb5ad621d
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Update#1 to f2
changeset: 7:c42ecff04e99
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Update#1 to f3
Interrupting the pull is safe
$ hg --config hooks.pretxnchangegroup.bad=false pull -q
transaction abort!
rollback completed
abort: pretxnchangegroup.bad hook exited with status 1
[255]
$ hg id
223311e70a6f tip
pull new changes down to the narrow clone. Should get 8 new changesets: 4
relevant to the narrow spec, and 4 ellipsis nodes gluing them all together.
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
added 9 changesets with 4 changes to 2 files
new changesets *:* (glob)
(run 'hg update' to get a working copy)
$ hg log -T '{rev}: {desc}\n'
13: Update#2 to f10
12: Update#2 to f8
11: Update#2 to f7
10: Update#2 to f2
9: Update#2 to f1
8: Update#1 to f8
7: Update#1 to f7
6: Update#1 to f2
5: Update#1 to f1
4: Commit f10
3: Commit f8
2: Commit f7
1: Commit f2
0: Commit f1
$ hg update tip
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
add a change and push it
$ echo "update#3 2" >> f2
$ hg commit -m "Update#3 to f2" f2
$ hg log f2 -T '{rev}: {desc}\n'
14: Update#3 to f2
10: Update#2 to f2
6: Update#1 to f2
1: Commit f2
$ hg push
pushing to ssh://user@dummy/master
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
$ cd ..
$ cd master
$ hg log f2 -T '{rev}: {desc}\n'
30: Update#3 to f2
21: Update#2 to f2
11: Update#1 to f2
1: Commit f2
$ hg log -l 3 -T '{rev}: {desc}\n'
30: Update#3 to f2
29: Update#2 to f10
28: Update#2 to f9
Can pull into repo with a single commit
$ cd ..
$ hg clone -q --narrow ssh://user@dummy/master narrow2 --include "f1" -r 0
$ cd narrow2
$ hg pull -q -r 1
transaction abort!
rollback completed
abort: pull failed on remote
[255]
Can use 'hg share':
$ cat >> $HGRCPATH <<EOF
> [extensions]
> share=
> EOF
$ cd ..
$ hg share narrow2 narrow2-share
updating working directory
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd narrow2-share
$ hg status
We should also be able to unshare without breaking everything:
$ hg unshare
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checked 1 changesets with 1 changes to 1 files