procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
$ cat >> fakepager.py <<EOF
> import sys
> printed = False
> for line in sys.stdin:
> sys.stdout.write('paged! %r\n' % line)
> printed = True
> if not printed:
> sys.stdout.write('paged empty output!\n')
> 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 >> $HGRCPATH <<EOF
> [ui]
> formatted = yes
> color = no
> [pager]
> pager = "$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 id 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 id
46106edeeb38 tip
We can control the pager from the config
$ hg log --limit 1 --config 'ui.paginate=False'
changeset: 10:46106edeeb38
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify a 10
$ hg log --limit 1 --config 'ui.paginate=0'
changeset: 10:46106edeeb38
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify a 10
$ hg log --limit 1 --config 'ui.paginate=1'
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'
explicit --pager=on should take precedence over other configurations
(issue5580)
$ cat >> $HGRCPATH <<EOF
> [ui]
> paginate = false
> EOF
$ hg log --limit 1 --pager=on
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'
$ cat >> $HGRCPATH <<EOF
> [ui]
> # true is default value of ui.paginate
> paginate = true
> EOF
$ hg log --limit 1 --pager=off
changeset: 10:46106edeeb38
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify a 10
We can enable the pager on id:
BROKEN: should be paged
$ hg --config pager.attend-id=yes id
46106edeeb38 tip
Setting attend-$COMMAND to a false value works, even with pager in
core:
$ 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
Command aliases should have same behavior as main command
$ hg history --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'
Abbreviated command alias should also be paged
$ hg hist -l 1
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'
Attend for an abbreviated command does not work
$ hg --config pager.attend-ident=true ident
46106edeeb38 tip
$ hg --config extensions.pager= --config pager.attend-ident=true ident
46106edeeb38 tip
Pager should not start if stdout is not a tty.
$ hg log -l1 -q --config ui.formatted=False
10:46106edeeb38
Pager should be disabled if pager.pager is empty (otherwise the output would
be silently lost.)
$ hg log -l1 -q --config pager.pager=
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'
#if no-chg
An invalid pager command name is reported sensibly if we don't have to
use shell=True in the subprocess call:
$ hg log --limit 3 --config pager.pager=this-command-better-never-exist
missing pager command 'this-command-better-never-exist', skipping pager
\x1b[0;33mchangeset: 10:46106edeeb38\x1b[0m (esc)
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify a 10
\x1b[0;33mchangeset: 9:6dd8ea7dd621\x1b[0m (esc)
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify a 9
\x1b[0;33mchangeset: 8:cff05a6312fe\x1b[0m (esc)
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify a 8
#endif
A complicated pager command gets worse behavior. Bonus points if you can
improve this. Windows apparently does this better, but only sometimes?
#if windows
$ hg log --limit 3 \
> --config pager.pager='this-command-better-never-exist --seriously' \
> 2>/dev/null || true
\x1b[0;33mchangeset: 10:46106edeeb38\x1b[0m (esc) (?)
tag: tip (?)
user: test (?)
date: Thu Jan 01 00:00:00 1970 +0000 (?)
summary: modify a 10 (?)
(?)
\x1b[0;33mchangeset: 9:6dd8ea7dd621\x1b[0m (esc) (?)
user: test (?)
date: Thu Jan 01 00:00:00 1970 +0000 (?)
summary: modify a 9 (?)
(?)
\x1b[0;33mchangeset: 8:cff05a6312fe\x1b[0m (esc) (?)
user: test (?)
date: Thu Jan 01 00:00:00 1970 +0000 (?)
summary: modify a 8 (?)
(?)
#else
$ hg log --limit 3 \
> --config pager.pager='this-command-better-never-exist --seriously' \
> 2>/dev/null || true
#endif
Pager works with shell aliases.
$ cat >> $HGRCPATH <<EOF
> [alias]
> echoa = !echo a
> EOF
$ hg echoa
a
BROKEN: should be paged
$ hg --config pager.attend-echoa=yes echoa
a
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]
A command that asks for paging using ui.pager() directly works:
$ hg blame a
paged! ' 0: a\n'
paged! ' 1: a 1\n'
paged! ' 2: a 2\n'
paged! ' 3: a 3\n'
paged! ' 4: a 4\n'
paged! ' 5: a 5\n'
paged! ' 6: a 6\n'
paged! ' 7: a 7\n'
paged! ' 8: a 8\n'
paged! ' 9: a 9\n'
paged! '10: a 10\n'
but not with HGPLAIN
$ HGPLAIN=1 hg blame a
0: a
1: a 1
2: a 2
3: a 3
4: a 4
5: a 5
6: a 6
7: a 7
8: a 8
9: a 9
10: a 10
explicit flags work too:
$ hg blame --pager=no a
0: a
1: a 1
2: a 2
3: a 3
4: a 4
5: a 5
6: a 6
7: a 7
8: a 8
9: a 9
10: a 10
A command with --output option:
$ hg cat -r0 a
paged! 'a\n'
$ hg cat -r0 a --output=-
paged! 'a\n'
$ hg cat -r0 a --output=out
$ hg export -r0
paged! '# HG changeset patch\n'
paged! '# User test\n'
paged! '# Date 0 0\n'
paged! '# Thu Jan 01 00:00:00 1970 +0000\n'
paged! '# Node ID 1f0dee641bb7258c56bd60e93edfa2405381c41e\n'
paged! '# Parent 0000000000000000000000000000000000000000\n'
paged! 'add a\n'
paged! '\n'
paged! '\x1b[0;1mdiff -r 000000000000 -r 1f0dee641bb7 a\x1b[0m\n'
paged! '\x1b[0;31;1m--- /dev/null\tThu Jan 01 00:00:00 1970 +0000\x1b[0m\n'
paged! '\x1b[0;32;1m+++ b/a\tThu Jan 01 00:00:00 1970 +0000\x1b[0m\n'
paged! '\x1b[0;35m@@ -0,0 +1,1 @@\x1b[0m\n'
paged! '\x1b[0;32m+a\x1b[0m\n'
$ hg export -r0 -o -
paged! '# HG changeset patch\n'
paged! '# User test\n'
paged! '# Date 0 0\n'
paged! '# Thu Jan 01 00:00:00 1970 +0000\n'
paged! '# Node ID 1f0dee641bb7258c56bd60e93edfa2405381c41e\n'
paged! '# Parent 0000000000000000000000000000000000000000\n'
paged! 'add a\n'
paged! '\n'
paged! '\x1b[0;1mdiff -r 000000000000 -r 1f0dee641bb7 a\x1b[0m\n'
paged! '\x1b[0;31;1m--- /dev/null\tThu Jan 01 00:00:00 1970 +0000\x1b[0m\n'
paged! '\x1b[0;32;1m+++ b/a\tThu Jan 01 00:00:00 1970 +0000\x1b[0m\n'
paged! '\x1b[0;35m@@ -0,0 +1,1 @@\x1b[0m\n'
paged! '\x1b[0;32m+a\x1b[0m\n'
$ hg export -r0 -o out
$ rm out
Put annotate in the ignore list for pager:
$ cat >> $HGRCPATH <<EOF
> [pager]
> ignore = annotate
> EOF
$ hg blame a
0: a
1: a 1
2: a 2
3: a 3
4: a 4
5: a 5
6: a 6
7: a 7
8: a 8
9: a 9
10: a 10
During pushbuffer, pager should not start:
$ cat > $TESTTMP/pushbufferpager.py <<EOF
> def uisetup(ui):
> ui.pushbuffer()
> ui.pager(b'mycmd')
> ui.write(b'content\n')
> ui.write(ui.popbuffer())
> EOF
$ echo append >> a
$ hg --config extensions.pushbuffer=$TESTTMP/pushbufferpager.py status --color=off
content
paged! 'M a\n'
Environment variables like LESS and LV are set automatically:
$ cat > $TESTTMP/printlesslv.py <<EOF
> import os
> import sys
> sys.stdin.read()
> for name in ['LESS', 'LV']:
> sys.stdout.write(('%s=%s\n') % (name, os.environ.get(name, '-')))
> sys.stdout.flush()
> EOF
$ cat >> $HGRCPATH <<EOF
> [alias]
> noop = log -r 0 -T ''
> [ui]
> formatted=1
> [pager]
> pager = "$PYTHON" $TESTTMP/printlesslv.py
> EOF
$ unset LESS
$ unset LV
$ hg noop --pager=on
LESS=FRX
LV=-c
$ LESS=EFGH hg noop --pager=on
LESS=EFGH
LV=-c