view tests/test-pager.t @ 37048:fc5e261915b9

wireproto: require POST for all HTTPv2 requests

Wire protocol version 1 transfers argument data via request
headers by default. This has historically caused problems because
servers institute limits on the length of individual HTTP headers
as well as the total size of all request headers. Mercurial servers
can advertise the maximum length of an individual header. But
there's no guarantee any intermediate HTTP agents will accept
headers up to that length.

In the existing wire protocol, server operators typically also
key off the HTTP request method to implement authentication.
For example, GET requests translate to read-only requests and
can be allowed. But read-write commands must use POST and require
authentication. This has typically worked because the only wire
protocol commands that use POST modify the repo (e.g. the
"unbundle" command).

There is an experimental feature to enable clients to transmit
argument data via POST request bodies. This is technically a
better and more robust solution. But we can't enable it by default
because of servers assuming POST means write access.

In version 2 of the wire protocol, the permissions of a request
are encoded in the URL. And with it being a new protocol in a new
URL space, we're not constrained by backwards compatibility
requirements.

This commit adopts the technically superior mechanism of using
HTTP request bodies to send argument data by requiring POST for
all commands. Strictly speaking, it may be possible to send
request bodies on GET requests. But my experience is that not all
HTTP stacks support this. POST pretty much always works. Using POST
for read-only operations does sacrifice some RESTful design
purity. But this API cares about practicality, not about being
in Roy T. Fielding's REST ivory tower.

There's a chance we may relax this restriction in the future. But
for now, I want to see how far we can get with a POST only API.

Differential Revision: https://phab.mercurial-scm.org/D2837

  $ 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.
  $ hg log --limit 3 \
  >   --config pager.pager='this-command-better-never-exist --seriously' \
  >  2>/dev/null || true

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', [], 'fortytwo', norepo=True)
  > def fortytwo(ui, *opts):
  >     ui.write('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
  $ 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('mycmd')
  >     ui.write('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
  > from __future__ import absolute_import
  > 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