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).
$ cat <<EOF >> $HGRCPATH
> [extensions]
> mq =
> [mq]
> git = keep
> [diff]
> nodates = 1
> EOF
init:
$ hg init repo
$ cd repo
$ echo a > a
$ hg ci -Am adda
adding a
$ echo a >> a
$ hg qnew -f p1
$ echo b >> a
$ hg qnew -f p2
$ echo c >> a
$ hg qnew -f p3
Fold in the middle of the queue:
(this tests also that editor is not invoked if '--edit' is not
specified)
$ hg qpop p1
popping p3
popping p2
now at: p1
$ hg qdiff
diff -r 07f494440405 a
--- a/a
+++ b/a
@@ -1,1 +1,2 @@
a
+a
$ HGEDITOR=cat hg qfold p2
$ grep git .hg/patches/p1 && echo 'git patch found!'
[1]
$ hg qser
p1
p3
$ hg qdiff
diff -r 07f494440405 a
--- a/a
+++ b/a
@@ -1,1 +1,3 @@
a
+a
+b
Fold with local changes:
$ echo d >> a
$ hg qfold p3
abort: local changes found, qrefresh first
[255]
$ hg diff -c .
diff -r 07f494440405 -r ???????????? a (glob)
--- a/a
+++ b/a
@@ -1,1 +1,3 @@
a
+a
+b
$ hg revert -a --no-backup
reverting a
Fold git patch into a regular patch, expect git patch:
$ echo a >> a
$ hg qnew -f regular
$ hg cp a aa
$ hg qnew --git -f git
$ hg qpop
popping git
now at: regular
$ hg qfold git
$ cat .hg/patches/regular
# HG changeset patch
# Parent ???????????????????????????????????????? (glob)
diff --git a/a b/a
--- a/a
+++ b/a
@@ -1,3 +1,4 @@
a
a
b
+a
diff --git a/a b/aa
copy from a
copy to aa
--- a/a
+++ b/aa
@@ -1,3 +1,4 @@
a
a
b
+a
$ hg qpop
popping regular
now at: p1
$ hg qdel regular
Fold regular patch into a git patch, expect git patch:
$ hg cp a aa
$ hg qnew --git -f git
$ echo b >> aa
$ hg qnew -f regular
$ hg qpop
popping regular
now at: git
$ hg qfold regular
$ cat .hg/patches/git
# HG changeset patch
# Parent ???????????????????????????????????????? (glob)
diff --git a/a b/aa
copy from a
copy to aa
--- a/a
+++ b/aa
@@ -1,3 +1,4 @@
a
a
b
+b
Test saving last-message.txt:
$ hg qrefresh -m "original message"
$ cat > $TESTTMP/commitfailure.py <<EOF
> from mercurial import error
> def reposetup(ui, repo):
> class commitfailure(repo.__class__):
> def commit(self, *args, **kwargs):
> raise error.Abort('emulating unexpected abort')
> repo.__class__ = commitfailure
> EOF
$ cat >> .hg/hgrc <<EOF
> [extensions]
> # this failure occurs before editor invocation
> commitfailure = $TESTTMP/commitfailure.py
> EOF
$ cat > $TESTTMP/editor.sh << EOF
> echo "==== before editing"
> cat \$1
> echo "===="
> (echo; echo "test saving last-message.txt") >> \$1
> EOF
$ hg qapplied
p1
git
$ hg tip --template "{files}\n"
aa
(test that editor is not invoked before transaction starting,
and that combination of '--edit' and '--message' doesn't abort execution)
$ rm -f .hg/last-message.txt
$ HGEDITOR="sh $TESTTMP/editor.sh" hg qfold -e -m MESSAGE p3
qrefresh interrupted while patch was popped! (revert --all, qpush to recover)
abort: emulating unexpected abort
[255]
$ test -f .hg/last-message.txt
[1]
(reset applied patches and directory status)
$ cat >> .hg/hgrc <<EOF
> [extensions]
> # this failure occurs after editor invocation
> commitfailure = !
> EOF
$ hg qapplied
p1
$ hg status -A aa
? aa
$ rm aa
$ hg status -m
M a
$ hg revert --no-backup -q a
$ hg qpush -q git
now at: git
(test that editor is invoked and commit message is saved into
"last-message.txt")
$ cat >> .hg/hgrc <<EOF
> [hooks]
> # this failure occurs after editor invocation
> pretxncommit.unexpectedabort = false
> EOF
$ rm -f .hg/last-message.txt
$ HGEDITOR="sh $TESTTMP/editor.sh" hg qfold -e p3
==== before editing
original message
HG: Enter commit message. Lines beginning with 'HG:' are removed.
HG: Leave message empty to use default message.
HG: --
HG: user: test
HG: branch 'default'
HG: added aa
HG: changed a
====
note: commit message saved in .hg/last-message.txt
transaction abort!
rollback completed
qrefresh interrupted while patch was popped! (revert --all, qpush to recover)
abort: pretxncommit.unexpectedabort hook exited with status 1
[255]
$ cat .hg/last-message.txt
original message
test saving last-message.txt
(confirm whether files listed up in the commit message editing are correct)
$ cat >> .hg/hgrc <<EOF
> [hooks]
> pretxncommit.unexpectedabort =
> EOF
$ hg status -u | while read f; do rm ${f}; done
$ hg revert --no-backup -q --all
$ hg qpush -q git
now at: git
$ hg qpush -q --move p3
now at: p3
$ hg status --rev "git^1" --rev . -arm
M a
A aa
$ cd ..