exchange: ensure all outgoing subrepo references are present before pushing
We've run into occasional problems with people committing a repo, and then
amending or rebasing in the subrepo. That makes it so that the revision in the
parent can't be checked out, and the problem gets propagated on push. Mercurial
already tries to defend against this sort of dangling reference by pushing *all*
subrepo revisions first. This reuses the checks that trigger warnings in
`hg verify` to bail on the push unless using `--force`.
I thought about putting this on the server side, but at that point, all of the
data has been transferred, only to bail out. Additionally, SCM Manager hosts
subrepos in a location that isn't nested in the parent, so normal subrepo code
would complain that the subrepo is missing when run on the server.
Because the push command pushes subrepos before calling this exchange code, a
subrepo will be pushed before the parent is verified. Not great, but no
dangling references are exchanged, so it solves the problem. This code isn't in
the loop that pushes the subrepos because:
1) the list of outgoing revisions is needed to limit the scope of the check
2) the loop only accesses the current revision, and therefore can miss
subrepos that were dropped in previous commits
3) this code is called when pushing a subrepo, so the protection is recursive
I'm not sure if there's a cheap check for the list of files in the outgoing
bundle. If there is, that would provide a fast path to bypass this check for
people not using subrepos (or if no subrepo changes were made). There's
probably also room for verifying other references like tags. But since that
doesn't break checkouts, it's much less of a problem.
Differential Revision: https://phab.mercurial-scm.org/D7616
#testcases obsstore-off obsstore-on
$ cat << EOF >> $HGRCPATH
> [extensions]
> amend =
> EOF
#if obsstore-on
$ cat << EOF >> $HGRCPATH
> [experimental]
> evolution.createmarkers = True
> EOF
#endif
Prepare parent repo
-------------------
$ hg init r
$ cd r
$ echo a > a
$ hg ci -Am0
adding a
Link first subrepo
------------------
$ echo 's = s' >> .hgsub
$ hg add .hgsub
$ hg init s
amend without .hgsub
$ hg amend s
abort: can't commit subrepos without .hgsub
[255]
amend with subrepo
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
A .hgsub
A .hgsubstate
A a
$ cat .hgsubstate
0000000000000000000000000000000000000000 s
Update subrepo
--------------
add new commit to be amended
$ echo a >> a
$ hg ci -m1
amend with dirty subrepo
$ echo a >> s/a
$ hg add -R s
adding s/a
$ hg amend
abort: uncommitted changes in subrepository "s"
(use --subrepos for recursive commit)
[255]
amend with modified subrepo
$ hg ci -R s -m0
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
M .hgsubstate
M a
$ cat .hgsubstate
f7b1eb17ad24730a1651fccd46c43826d1bbc2ac s
revert subrepo change
$ hg up -R s -q null
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
M a
Link another subrepo
--------------------
add new commit to be amended
$ echo b >> b
$ hg ci -qAm2
also checks if non-subrepo change is included
$ echo a >> a
amend with another subrepo
$ hg init t
$ echo b >> t/b
$ hg ci -R t -Am0
adding b
$ echo 't = t' >> .hgsub
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
M .hgsub
M .hgsubstate
M a
A b
$ cat .hgsubstate
0000000000000000000000000000000000000000 s
bfb1a4fb358498a9533dabf4f2043d94162f1fcd t
Unlink one subrepo
------------------
add new commit to be amended
$ echo a >> a
$ hg ci -m3
$ echo 't = t' > .hgsub
--interactive won't silently ignore dirty subrepos
$ echo modified > t/b
$ hg amend --interactive --config ui.interactive=True
abort: uncommitted changes in subrepository "t"
[255]
$ hg amend --interactive --config ui.interactive=True --config ui.commitsubrepos=True
abort: uncommitted changes in subrepository "t"
[255]
$ hg -R t revert -q --all --no-backup
amend with one subrepo dropped
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
M .hgsub
M .hgsubstate
M a
$ cat .hgsubstate
bfb1a4fb358498a9533dabf4f2043d94162f1fcd t
Unlink subrepos completely
--------------------------
add new commit to be amended
$ echo a >> a
$ hg ci -m3
amend with .hgsub removed
$ hg rm .hgsub
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
M a
R .hgsub
R .hgsubstate
broken repositories will refuse to push
#if obsstore-off
$ hg up -q -C 2
#else
$ hg up -q -C 6
#endif
$ echo c >> t/b
$ hg amend -q -R t
$ hg init ../dest
$ hg init ../dest/t
$ hg init ../dest/s
$ hg push -q ../dest
abort: subrepo 't' is hidden in revision 04aa62396ec6 (obsstore-on !)
abort: subrepo 't' not found in revision 04aa62396ec6 (obsstore-off !)
[255]
... unless forced
$ hg push --force -q ../dest
$ hg verify -R ../dest
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checked 5 changesets with 12 changes to 4 files
checking subrepo links
subrepo 't' not found in revision 04aa62396ec6
subrepo 't' not found in revision 6bce99600681
$ cd ..