transaction: quietly rollback if no other changes than temporary files
If no actual change have been made, we don't really need to roll them back. We
only have to cleanup some temporary files and it seems reasonable to do that
quietly.
This will help us to use the transaction in wider context¹ without impacting the
user experience.
[1] as in Python context managers that lives longer.
$ cat >> fakepager.py <<EOF
> import sys
> for line in sys.stdin:
> sys.stdout.write('paged! %r\n' % line)
> EOF
Enable ui.formatted because pager won't fire without it, and set up
pager and tell it to use our fake pager that lets us see when the
pager was running.
$ cat >> $HGRCPATH <<EOF
> [ui]
> formatted = yes
> color = no
> [extensions]
> pager=
> [pager]
> pager = "$PYTHON" $TESTTMP/fakepager.py
> EOF
$ hg init repo
$ cd repo
$ echo a >> a
$ hg add a
$ hg ci -m 'add a'
$ for x in `"$PYTHON" $TESTDIR/seq.py 1 10`; do
> echo a $x >> a
> hg ci -m "modify a $x"
> done
By default diff and log are paged, but summary is not:
$ hg diff -c 2 --pager=yes
paged! 'diff -r f4be7687d414 -r bce265549556 a\n'
paged! '--- a/a\tThu Jan 01 00:00:00 1970 +0000\n'
paged! '+++ b/a\tThu Jan 01 00:00:00 1970 +0000\n'
paged! '@@ -1,2 +1,3 @@\n'
paged! ' a\n'
paged! ' a 1\n'
paged! '+a 2\n'
$ hg log --limit 2
paged! 'changeset: 10:46106edeeb38\n'
paged! 'tag: tip\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 10\n'
paged! '\n'
paged! 'changeset: 9:6dd8ea7dd621\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 9\n'
paged! '\n'
$ hg summary
parent: 10:46106edeeb38 tip
modify a 10
branch: default
commit: (clean)
update: (current)
phases: 11 draft
We can enable the pager on summary:
$ hg --config pager.attend-summary=yes summary
paged! 'parent: 10:46106edeeb38 tip\n'
paged! ' modify a 10\n'
paged! 'branch: default\n'
paged! 'commit: (clean)\n'
paged! 'update: (current)\n'
paged! 'phases: 11 draft\n'
$ hg --config pager.attend-diff=no diff -c 2
diff -r f4be7687d414 -r bce265549556 a
--- a/a Thu Jan 01 00:00:00 1970 +0000
+++ b/a Thu Jan 01 00:00:00 1970 +0000
@@ -1,2 +1,3 @@
a
a 1
+a 2
If we completely change the attend list that's respected:
$ hg --config pager.attend=summary diff -c 2
diff -r f4be7687d414 -r bce265549556 a
--- a/a Thu Jan 01 00:00:00 1970 +0000
+++ b/a Thu Jan 01 00:00:00 1970 +0000
@@ -1,2 +1,3 @@
a
a 1
+a 2
If 'log' is in attend, then 'history' should also be paged:
$ hg history --limit 2 --config pager.attend=log
paged! 'changeset: 10:46106edeeb38\n'
paged! 'tag: tip\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 10\n'
paged! '\n'
paged! 'changeset: 9:6dd8ea7dd621\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 9\n'
paged! '\n'
Possible bug: history is explicitly ignored in pager config, but
because log is in the attend list it still gets pager treatment.
$ hg history --limit 2 --config pager.attend=log \
> --config pager.ignore=history
paged! 'changeset: 10:46106edeeb38\n'
paged! 'tag: tip\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 10\n'
paged! '\n'
paged! 'changeset: 9:6dd8ea7dd621\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 9\n'
paged! '\n'
Possible bug: history is explicitly marked as attend-history=no, but
it doesn't fail to get paged because log is still in the attend list.
$ hg history --limit 2 --config pager.attend-history=no
paged! 'changeset: 10:46106edeeb38\n'
paged! 'tag: tip\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 10\n'
paged! '\n'
paged! 'changeset: 9:6dd8ea7dd621\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 9\n'
paged! '\n'
Possible bug: disabling pager for log but enabling it for history
doesn't result in history being paged.
$ hg history --limit 2 --config pager.attend-log=no \
> --config pager.attend-history=yes
changeset: 10:46106edeeb38
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify a 10
changeset: 9:6dd8ea7dd621
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify a 9
Pager should not start if stdout is not a tty.
$ hg log -l1 -q --config ui.formatted=False
10:46106edeeb38
Pager with color enabled allows colors to come through by default,
even though stdout is no longer a tty.
$ cat >> $HGRCPATH <<EOF
> [ui]
> color = always
> [color]
> mode = ansi
> EOF
$ hg log --limit 3
paged! '\x1b[0;33mchangeset: 10:46106edeeb38\x1b[0m\n'
paged! 'tag: tip\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 10\n'
paged! '\n'
paged! '\x1b[0;33mchangeset: 9:6dd8ea7dd621\x1b[0m\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 9\n'
paged! '\n'
paged! '\x1b[0;33mchangeset: 8:cff05a6312fe\x1b[0m\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 8\n'
paged! '\n'
Pager works with shell aliases.
$ cat >> $HGRCPATH <<EOF
> [alias]
> echoa = !echo a
> EOF
$ hg echoa
a
$ hg --config pager.attend-echoa=yes echoa
paged! 'a\n'
Pager attributes should be copied to mq repo. Otherwise pager would be started
twice and color mode would be lost.
$ cat >> $HGRCPATH <<EOF
> [extensions]
> mq =
> EOF
$ hg init --mq
$ hg qnew foo.patch
$ hg qpop
popping foo.patch
patch queue now empty
$ hg ci --mq -m 'commit patches'
$ hg log --mq --debug
starting pager for command 'extension-via-attend-log'
paged! '\x1b[0;33mchangeset: 0:6cc2ded15503e368aaf76b6cc3d12f320c9e3b87\x1b[0m\n'
paged! 'tag: tip\n'
paged! 'phase: draft\n'
paged! 'parent: -1:0000000000000000000000000000000000000000\n'
paged! 'parent: -1:0000000000000000000000000000000000000000\n'
paged! 'manifest: 0:4980de1ae1b612014d5bcfa9507da84ce8891daa\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'files+: .hgignore foo.patch series\n'
paged! 'extra: branch=default\n'
paged! 'description:\n'
paged! 'commit patches\n'
paged! '\n'
paged! '\n'
Pager works with hg aliases including environment variables.
$ cat >> $HGRCPATH <<'EOF'
> [alias]
> printa = log -T "$A\n" -r 0
> EOF
$ A=1 hg --config pager.attend-printa=yes printa
paged! '1\n'
$ A=2 hg --config pager.attend-printa=yes printa
paged! '2\n'
Something that's explicitly attended is still not paginated if the
pager is globally set to off using a flag:
$ A=2 hg --config pager.attend-printa=yes printa --pager=no
2
Pager should not override the exit code of other commands
$ cat >> $TESTTMP/fortytwo.py <<'EOF'
> from mercurial import commands, registrar
> cmdtable = {}
> command = registrar.command(cmdtable)
> @command(b'fortytwo', [], b'fortytwo', norepo=True)
> def fortytwo(ui, *opts):
> ui.write(b'42\n')
> return 42
> EOF
$ cat >> $HGRCPATH <<'EOF'
> [extensions]
> fortytwo = $TESTTMP/fortytwo.py
> EOF
$ hg fortytwo --pager=on
paged! '42\n'
[42]