ui: add special-purpose atexit functionality
In spite of its longstanding use, Python's built-in atexit code is
not suitable for Mercurial's purposes, for several reasons:
* Handlers run after application code has finished.
* Because of this, the code that runs handlers swallows exceptions
(since there's no possible stacktrace to associate errors with).
If we're lucky, we'll get something spat out to stderr (if stderr
still works), which of course isn't any use in a big deployment
where it's important that exceptions get logged and aggregated.
* Mercurial's current atexit handlers make unfortunate assumptions
about process state (specifically stdio) that, coupled with the
above problems, make it impossible to deal with certain categories
of error (try "hg status > /dev/full" on a Linux box).
* In Python 3, the atexit implementation is completely hidden, so
we can't hijack the platform's atexit code to run handlers at a
time of our choosing.
As a result, here's a perfectly cromulent atexit-like implementation
over which we have control. This lets us decide exactly when the
handlers run (after each request has completed), and control what
the process state is when that occurs (and afterwards).
$ echo '[extensions]' >> $HGRCPATH
$ echo 'hgext.mq =' >> $HGRCPATH
$ hg init repo
$ cd repo
$ echo foo > foo
$ hg ci -qAm 'add a file'
$ hg qinit
$ hg qnew foo
$ echo foo >> foo
$ hg qrefresh -m 'append foo'
$ hg qnew bar
$ echo bar >> foo
$ hg qrefresh -m 'append bar'
Try to operate on public mq changeset
$ hg qpop
popping bar
now at: foo
$ hg phase --public qbase
$ echo babar >> foo
$ hg qref
abort: cannot qrefresh public revision
(see 'hg help phases' for details)
[255]
$ hg revert -a
reverting foo
$ hg qpop
abort: popping would remove a public revision
(see 'hg help phases' for details)
[255]
$ hg qfold bar
abort: cannot qrefresh public revision
(see 'hg help phases' for details)
[255]
$ hg revert -a
reverting foo
restore state for remaining test
$ hg qpush
applying bar
now at: bar
try to commit on top of a patch
$ echo quux >> foo
$ hg ci -m 'append quux'
abort: cannot commit over an applied mq patch
[255]
cheat a bit...
$ mv .hg/patches .hg/patches2
$ hg ci -m 'append quux'
$ mv .hg/patches2 .hg/patches
qpop/qrefresh on the wrong revision
$ hg qpop
abort: popping would remove a revision not managed by this patch queue
[255]
$ hg qpop -n patches
using patch queue: $TESTTMP/repo/.hg/patches (glob)
abort: popping would remove a revision not managed by this patch queue
[255]
$ hg qrefresh
abort: working directory revision is not qtip
[255]
$ hg up -C qtip
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg qpop
abort: popping would remove a revision not managed by this patch queue
[255]
$ hg qrefresh
abort: cannot qrefresh a revision with children
[255]
$ hg tip --template '{rev} {desc}\n'
3 append quux
qpush warning branchheads
$ cd ..
$ hg init branchy
$ cd branchy
$ echo q > q
$ hg add q
$ hg qnew -f qp
$ hg qpop
popping qp
patch queue now empty
$ echo a > a
$ hg ci -Ama
adding a
$ hg up null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg branch b
marked working directory as branch b
(branches are permanent and global, did you want a bookmark?)
$ echo c > c
$ hg ci -Amc
adding c
$ hg merge default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -mmerge
$ hg up default
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg log
changeset: 2:65309210bf4e
branch: b
tag: tip
parent: 1:707adb4c8ae1
parent: 0:cb9a9f314b8b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: merge
changeset: 1:707adb4c8ae1
branch: b
parent: -1:000000000000
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: c
changeset: 0:cb9a9f314b8b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a
$ hg qpush
applying qp
now at: qp
Testing applied patches, push and --force
$ cd ..
$ hg init forcepush
$ cd forcepush
$ echo a > a
$ hg ci -Am adda
adding a
$ echo a >> a
$ hg ci -m changea
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg branch branch
marked working directory as branch branch
(branches are permanent and global, did you want a bookmark?)
$ echo b > b
$ hg ci -Am addb
adding b
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg --cwd .. clone -r 0 forcepush forcepush2
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo a >> a
$ hg qnew patch
Pushing applied patch with --rev without --force
$ hg push -r . ../forcepush2
pushing to ../forcepush2
abort: source has mq patches applied
[255]
Pushing applied patch with branchhash, without --force
$ hg push ../forcepush2#default
pushing to ../forcepush2
abort: source has mq patches applied
[255]
Pushing revs excluding applied patch
$ hg push --new-branch -r 'branch(branch)' -r 2 ../forcepush2
pushing to ../forcepush2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
Pushing applied patch with --force
$ hg phase --force --secret 'mq()'
$ hg push --force -r default ../forcepush2
pushing to ../forcepush2
searching for changes
no changes found (ignored 1 secret changesets)
[1]
$ hg phase --draft 'mq()'
$ hg push --force -r default ../forcepush2
pushing to ../forcepush2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
$ cd ..