cmdstate: introduce a "saver" contextmanager and use it in place of save()
Previously, the state was only saved in some paths out of these functions. This
can be problematic, if the user ctrl-c's (or `kill -9`'s) the process, or we
exit out of `relocate` for anything besides the "expected" reason, we won't
record that we were in the middle of an evolve.
One of our users has discovered that this leaves hg in a weird state; the user
did something like this:
```
$ hg evolve
<something goes wrong with the merge tool, hits ctrl-c>
<deals with the merge conflicts>
$ hg evolve --continue
abort: no interrupted evolve to continue
$ hg evolve
abort: uncommitted changes
# Note: commands.status.verbose=True is set.
$ hg status
M foo
# The repository is in an unfinished *update* state.
# No unresolved merge conflicts
# To continue: hg update
```
The user did an `hg update`, but it didn't actually do anything besides take it
out of the unfinished update state (the files were still dirty in the working
directory).
=====================
Test workflow options
=====================
$ . "$TESTDIR/testlib/topic_setup.sh"
$ . "$TESTDIR/testlib/common.sh"
Test single head enforcing - Setup
=============================================
$ hg init single-head-server
$ cd single-head-server
$ cat <<EOF >> .hg/hgrc
> [phases]
> publish = no
> [experimental]
> enforce-single-head = yes
> evolution = all
> EOF
$ mkcommit ROOT
$ mkcommit c_dA0
$ cd ..
$ hg clone single-head-server client
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test single head enforcing - with branch only
---------------------------------------------
$ cd client
continuing the current defaultbranch
$ mkcommit c_dB0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
creating a new branch
$ hg up 'desc("ROOT")'
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ hg branch branch_A
marked working directory as branch branch_A
(branches are permanent and global, did you want a bookmark?)
$ mkcommit c_aC0
$ hg push --new-branch
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
Create a new head on the default branch
$ hg up 'desc("c_dA0")'
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkcommit c_dD0
created new head
(consider using topic for lightweight branches. See 'hg help topic')
$ hg push -f
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
transaction abort!
rollback completed
abort: 2 heads on "default"
(286d02a6e2a2, 9bf953aa81f6)
[255]
remerge them
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ mkcommit c_dE0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
Test single head enforcing - with topic
---------------------------------------
pushing a new topic
$ hg topic foo
marked working directory as topic: foo
$ mkcommit c_dF0
active topic 'foo' grew its first changeset
(see 'hg help topics' for more information)
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
pushing a new topo branch (with a topic)
$ hg up 'desc("c_dD0")'
0 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ hg topic bar
marked working directory as topic: bar
$ mkcommit c_dG0
active topic 'bar' grew its first changeset
(see 'hg help topics' for more information)
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
detect multiple heads on the topic
$ mkcommit c_dH0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
$ hg up 'desc("c_dG0")'
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkcommit c_dI0
$ hg push -f
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
transaction abort!
rollback completed
abort: 2 heads on "default:bar"
(5194f5dcd542, 48a01453c1c5)
[255]
merge works fine
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ mkcommit c_dJ0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
Test single head enforcing - by phase move
------------------------------------------
$ hg -R ../single-head-server phase --public 'desc("c_dJ0")'
abort: 2 heads on "default"
(6ed1df20edb1, 678bca4de98c)
[255]
Test single head enforcing - after rewrite
------------------------------------------
$ hg up foo
switching to topic foo
3 files updated, 0 files merged, 4 files removed, 0 files unresolved
$ hg commit --amend -m c_dF1
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 1 files (+1 heads)
1 new obsolescence markers
obsoleted 1 changesets