view tests/test-status-color.t @ 39561:d06834e0f48e

wireprotov2peer: stream decoded responses Previously, wire protocol version 2 would buffer all response data. Only once all data was received did we CBOR decode it and resolve the future associated with the command. This was obviously not desirable. In future commits that introduce large response payloads, this caused significant memory bloat and slowed down client operations due to waiting on the server. This commit refactors the response handling code so that response data can be streamed. Command response objects now contain a buffered CBOR decoder. As new data arrives, it is fed into the decoder. Decoded objects are made available to the generator as they are decoded. Because there is a separate thread processing incoming frames and feeding data into the response object, there is the potential for race conditions when mutating response objects. So a lock has been added to guard access to critical state variables. Because the generator emitting decoded objects needs to wait on those objects to become available, we've added an Event for the generator to wait on so it doesn't busy loop. This does mean there is the potential for deadlocks. And I'm pretty sure they can occur in some scenarios. We already have a handful of TODOs around this. But I've added some more. Fixing this will likely require moving the background thread receiving frames into clienthandler. We likely would have done this anyway when implementing the client bits for the SSH transport. Test output changes because the initial CBOR map holding the overall response state is now always handled internally by the response object. Differential Revision: https://phab.mercurial-scm.org/D4474
author Gregory Szorc <gregory.szorc@gmail.com>
date Wed, 29 Aug 2018 15:17:11 -0700
parents ddc1da134772
children 34d9846023e6
line wrap: on
line source

  $ cat <<EOF >> $HGRCPATH
  > [ui]
  > color = always
  > [color]
  > mode = ansi
  > EOF
Terminfo codes compatibility fix
  $ echo "color.none=0" >> $HGRCPATH

  $ hg init repo1
  $ cd repo1
  $ mkdir a b a/1 b/1 b/2
  $ touch in_root a/in_a b/in_b a/1/in_a_1 b/1/in_b_1 b/2/in_b_2

hg status in repo root:

  $ hg status
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/1/in_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/in_a\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/in_b\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_root\x1b[0m (esc)

  $ hg status --color=debug
  [status.unknown|? ][status.unknown|a/1/in_a_1]
  [status.unknown|? ][status.unknown|a/in_a]
  [status.unknown|? ][status.unknown|b/1/in_b_1]
  [status.unknown|? ][status.unknown|b/2/in_b_2]
  [status.unknown|? ][status.unknown|b/in_b]
  [status.unknown|? ][status.unknown|in_root]
HGPLAIN disables color
  $ HGPLAIN=1 hg status --color=debug
  ? a/1/in_a_1 (glob)
  ? a/in_a (glob)
  ? b/1/in_b_1 (glob)
  ? b/2/in_b_2 (glob)
  ? b/in_b (glob)
  ? in_root
HGPLAINEXCEPT=color does not disable color
  $ HGPLAINEXCEPT=color hg status --color=debug
  [status.unknown|? ][status.unknown|a/1/in_a_1] (glob)
  [status.unknown|? ][status.unknown|a/in_a] (glob)
  [status.unknown|? ][status.unknown|b/1/in_b_1] (glob)
  [status.unknown|? ][status.unknown|b/2/in_b_2] (glob)
  [status.unknown|? ][status.unknown|b/in_b] (glob)
  [status.unknown|? ][status.unknown|in_root]

hg status with template
  $ hg status -T "{label('red', path)}\n" --color=debug
  [red|a/1/in_a_1]
  [red|a/in_a]
  [red|b/1/in_b_1]
  [red|b/2/in_b_2]
  [red|b/in_b]
  [red|in_root]

hg status . in repo root:

  $ hg status .
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/1/in_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/in_a\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/in_b\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_root\x1b[0m (esc)

  $ hg status --cwd a
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/1/in_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/in_a\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/in_b\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_root\x1b[0m (esc)
  $ hg status --cwd a .
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m1/in_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_a\x1b[0m (esc)
  $ hg status --cwd a ..
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m1/in_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_a\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../b/1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../b/2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../b/in_b\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../in_root\x1b[0m (esc)

  $ hg status --cwd b
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/1/in_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/in_a\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/in_b\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_root\x1b[0m (esc)
  $ hg status --cwd b .
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_b\x1b[0m (esc)
  $ hg status --cwd b ..
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../a/1/in_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../a/in_a\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_b\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../in_root\x1b[0m (esc)

  $ hg status --cwd a/1
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/1/in_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/in_a\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/in_b\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_root\x1b[0m (esc)
  $ hg status --cwd a/1 .
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_a_1\x1b[0m (esc)
  $ hg status --cwd a/1 ..
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../in_a\x1b[0m (esc)

  $ hg status --cwd b/1
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/1/in_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/in_a\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/in_b\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_root\x1b[0m (esc)
  $ hg status --cwd b/1 .
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_b_1\x1b[0m (esc)
  $ hg status --cwd b/1 ..
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../in_b\x1b[0m (esc)

  $ hg status --cwd b/2
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/1/in_a_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4ma/in_a\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/2/in_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4mb/in_b\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_root\x1b[0m (esc)
  $ hg status --cwd b/2 .
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_b_2\x1b[0m (esc)
  $ hg status --cwd b/2 ..
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../1/in_b_1\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4min_b_2\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4m../in_b\x1b[0m (esc)

Make sure --color=never works
  $ hg status --color=never
  ? a/1/in_a_1
  ? a/in_a
  ? b/1/in_b_1
  ? b/2/in_b_2
  ? b/in_b
  ? in_root

Make sure ui.formatted=False works
  $ hg status --color=auto --config ui.formatted=False
  ? a/1/in_a_1
  ? a/in_a
  ? b/1/in_b_1
  ? b/2/in_b_2
  ? b/in_b
  ? in_root

  $ cd ..

  $ hg init repo2
  $ cd repo2
  $ touch modified removed deleted ignored
  $ echo "^ignored$" > .hgignore
  $ hg ci -A -m 'initial checkin'
  \x1b[0;32madding .hgignore\x1b[0m (esc)
  \x1b[0;32madding deleted\x1b[0m (esc)
  \x1b[0;32madding modified\x1b[0m (esc)
  \x1b[0;32madding removed\x1b[0m (esc)
  $ hg log --color=debug
  [log.changeset changeset.draft|changeset:   0:389aef86a55e]
  [log.tag|tag:         tip]
  [log.user|user:        test]
  [log.date|date:        Thu Jan 01 00:00:00 1970 +0000]
  [log.summary|summary:     initial checkin]
  
  $ hg log -Tcompact --color=debug
  [log.changeset changeset.draft|0][tip]   [log.node|389aef86a55e]   [log.date|1970-01-01 00:00 +0000]   [log.user|test]
    [ui.note log.description|initial checkin]
  
Labels on empty strings should not be displayed, labels on custom
templates should be.

  $ hg log --color=debug -T '{label("my.label",author)}\n{label("skipped.label","")}'
  [my.label|test]
  $ touch modified added unknown ignored
  $ hg add added
  $ hg remove removed
  $ rm deleted

hg status:

  $ hg status
  \x1b[0;32;1mA \x1b[0m\x1b[0;32;1madded\x1b[0m (esc)
  \x1b[0;31;1mR \x1b[0m\x1b[0;31;1mremoved\x1b[0m (esc)
  \x1b[0;36;1;4m! \x1b[0m\x1b[0;36;1;4mdeleted\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4munknown\x1b[0m (esc)

hg status modified added removed deleted unknown never-existed ignored:

  $ hg status modified added removed deleted unknown never-existed ignored
  never-existed: * (glob)
  \x1b[0;32;1mA \x1b[0m\x1b[0;32;1madded\x1b[0m (esc)
  \x1b[0;31;1mR \x1b[0m\x1b[0;31;1mremoved\x1b[0m (esc)
  \x1b[0;36;1;4m! \x1b[0m\x1b[0;36;1;4mdeleted\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4munknown\x1b[0m (esc)

  $ hg copy modified copied

hg status -C:

  $ hg status -C
  \x1b[0;32;1mA \x1b[0m\x1b[0;32;1madded\x1b[0m (esc)
  \x1b[0;32;1mA \x1b[0m\x1b[0;32;1mcopied\x1b[0m (esc)
  \x1b[0;0m  modified\x1b[0m (esc)
  \x1b[0;31;1mR \x1b[0m\x1b[0;31;1mremoved\x1b[0m (esc)
  \x1b[0;36;1;4m! \x1b[0m\x1b[0;36;1;4mdeleted\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4munknown\x1b[0m (esc)

hg status -A:

  $ hg status -A
  \x1b[0;32;1mA \x1b[0m\x1b[0;32;1madded\x1b[0m (esc)
  \x1b[0;32;1mA \x1b[0m\x1b[0;32;1mcopied\x1b[0m (esc)
  \x1b[0;0m  modified\x1b[0m (esc)
  \x1b[0;31;1mR \x1b[0m\x1b[0;31;1mremoved\x1b[0m (esc)
  \x1b[0;36;1;4m! \x1b[0m\x1b[0;36;1;4mdeleted\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4munknown\x1b[0m (esc)
  \x1b[0;30;1mI \x1b[0m\x1b[0;30;1mignored\x1b[0m (esc)
  \x1b[0;0mC \x1b[0m\x1b[0;0m.hgignore\x1b[0m (esc)
  \x1b[0;0mC \x1b[0m\x1b[0;0mmodified\x1b[0m (esc)


hg status -A (with terminfo color):

#if tic

  $ mkdir "$TESTTMP/terminfo"
  $ TERMINFO="$TESTTMP/terminfo" tic "$TESTDIR/hgterm.ti"
  $ TERM=hgterm TERMINFO="$TESTTMP/terminfo" hg status --config color.mode=terminfo -A
  \x1b[30m\x1b[32m\x1b[1mA \x1b[30m\x1b[30m\x1b[32m\x1b[1madded\x1b[30m (esc)
  \x1b[30m\x1b[32m\x1b[1mA \x1b[30m\x1b[30m\x1b[32m\x1b[1mcopied\x1b[30m (esc)
  \x1b[30m\x1b[30m  modified\x1b[30m (esc)
  \x1b[30m\x1b[31m\x1b[1mR \x1b[30m\x1b[30m\x1b[31m\x1b[1mremoved\x1b[30m (esc)
  \x1b[30m\x1b[36m\x1b[1m\x1b[4m! \x1b[30m\x1b[30m\x1b[36m\x1b[1m\x1b[4mdeleted\x1b[30m (esc)
  \x1b[30m\x1b[35m\x1b[1m\x1b[4m? \x1b[30m\x1b[30m\x1b[35m\x1b[1m\x1b[4munknown\x1b[30m (esc)
  \x1b[30m\x1b[30m\x1b[1mI \x1b[30m\x1b[30m\x1b[30m\x1b[1mignored\x1b[30m (esc)
  \x1b[30m\x1b[30mC \x1b[30m\x1b[30m\x1b[30m.hgignore\x1b[30m (esc)
  \x1b[30m\x1b[30mC \x1b[30m\x1b[30m\x1b[30mmodified\x1b[30m (esc)

The user can define effects with raw terminfo codes:

  $ cat <<EOF >> $HGRCPATH
  > # Completely bogus code for dim
  > terminfo.dim = \E[88m
  > # We can override what's in the terminfo database, too
  > terminfo.bold = \E[2m
  > EOF
  $ TERM=hgterm TERMINFO="$TESTTMP/terminfo" hg status --config color.mode=terminfo --config color.status.clean=dim -A
  \x1b[30m\x1b[32m\x1b[2mA \x1b[30m\x1b[30m\x1b[32m\x1b[2madded\x1b[30m (esc)
  \x1b[30m\x1b[32m\x1b[2mA \x1b[30m\x1b[30m\x1b[32m\x1b[2mcopied\x1b[30m (esc)
  \x1b[30m\x1b[30m  modified\x1b[30m (esc)
  \x1b[30m\x1b[31m\x1b[2mR \x1b[30m\x1b[30m\x1b[31m\x1b[2mremoved\x1b[30m (esc)
  \x1b[30m\x1b[36m\x1b[2m\x1b[4m! \x1b[30m\x1b[30m\x1b[36m\x1b[2m\x1b[4mdeleted\x1b[30m (esc)
  \x1b[30m\x1b[35m\x1b[2m\x1b[4m? \x1b[30m\x1b[30m\x1b[35m\x1b[2m\x1b[4munknown\x1b[30m (esc)
  \x1b[30m\x1b[30m\x1b[2mI \x1b[30m\x1b[30m\x1b[30m\x1b[2mignored\x1b[30m (esc)
  \x1b[30m\x1b[88mC \x1b[30m\x1b[30m\x1b[88m.hgignore\x1b[30m (esc)
  \x1b[30m\x1b[88mC \x1b[30m\x1b[30m\x1b[88mmodified\x1b[30m (esc)

#endif


  $ echo "^ignoreddir$" > .hgignore
  $ mkdir ignoreddir
  $ touch ignoreddir/file

hg status ignoreddir/file:

  $ hg status ignoreddir/file

hg status -i ignoreddir/file:

  $ hg status -i ignoreddir/file
  \x1b[0;30;1mI \x1b[0m\x1b[0;30;1mignoreddir/file\x1b[0m (esc)
  $ cd ..

check 'status -q' and some combinations

  $ hg init repo3
  $ cd repo3
  $ touch modified removed deleted ignored
  $ echo "^ignored$" > .hgignore
  $ hg commit -A -m 'initial checkin'
  \x1b[0;32madding .hgignore\x1b[0m (esc)
  \x1b[0;32madding deleted\x1b[0m (esc)
  \x1b[0;32madding modified\x1b[0m (esc)
  \x1b[0;32madding removed\x1b[0m (esc)
  $ touch added unknown ignored
  $ hg add added
  $ echo "test" >> modified
  $ hg remove removed
  $ rm deleted
  $ hg copy modified copied

test unknown color

  $ hg --config color.status.modified=periwinkle status
  ignoring unknown color/effect 'periwinkle' (configured in color.status.modified)
  ignoring unknown color/effect 'periwinkle' (configured in color.status.modified)
  ignoring unknown color/effect 'periwinkle' (configured in color.status.modified)
  M modified
  \x1b[0;32;1mA \x1b[0m\x1b[0;32;1madded\x1b[0m (esc)
  \x1b[0;32;1mA \x1b[0m\x1b[0;32;1mcopied\x1b[0m (esc)
  \x1b[0;31;1mR \x1b[0m\x1b[0;31;1mremoved\x1b[0m (esc)
  \x1b[0;36;1;4m! \x1b[0m\x1b[0;36;1;4mdeleted\x1b[0m (esc)
  \x1b[0;35;1;4m? \x1b[0m\x1b[0;35;1;4munknown\x1b[0m (esc)

Run status with 2 different flags.
Check if result is the same or different.
If result is not as expected, raise error

  $ assert() {
  >     hg status $1 > ../a
  >     hg status $2 > ../b
  >     if diff ../a ../b > /dev/null; then
  >         out=0
  >     else
  >         out=1
  >     fi
  >     if [ $3 -eq 0 ]; then
  >         df="same"
  >     else
  >         df="different"
  >     fi
  >     if [ $out -ne $3 ]; then
  >         echo "Error on $1 and $2, should be $df."
  >     fi
  > }

assert flag1 flag2 [0-same | 1-different]

  $ assert "-q" "-mard"      0
  $ assert "-A" "-marduicC"  0
  $ assert "-qA" "-mardcC"   0
  $ assert "-qAui" "-A"      0
  $ assert "-qAu" "-marducC" 0
  $ assert "-qAi" "-mardicC" 0
  $ assert "-qu" "-u"        0
  $ assert "-q" "-u"         1
  $ assert "-m" "-a"         1
  $ assert "-r" "-d"         1
  $ cd ..

test 'resolve -l'

  $ hg init repo4
  $ cd repo4
  $ echo "file a" > a
  $ echo "file b" > b
  $ hg add a b
  $ hg commit -m "initial"
  $ echo "file a change 1" > a
  $ echo "file b change 1" > b
  $ hg commit -m "head 1"
  $ hg update 0
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo "file a change 2" > a
  $ echo "file b change 2" > b
  $ hg commit -m "head 2"
  created new head
  $ hg merge
  merging a
  merging b
  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
  warning: conflicts while merging b! (edit, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 2 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  [1]
  $ hg resolve -m b

hg resolve with one unresolved, one resolved:

  $ hg resolve -l
  \x1b[0;31;1mU \x1b[0m\x1b[0;31;1ma\x1b[0m (esc)
  \x1b[0;32;1mR \x1b[0m\x1b[0;32;1mb\x1b[0m (esc)

color coding of error message with current availability of curses

  $ hg unknowncommand > /dev/null
  hg: unknown command 'unknowncommand'
  (use 'hg help' for a list of commands)
  [255]

color coding of error message without curses

  $ echo 'raise ImportError' > curses.py
  $ PYTHONPATH=`pwd`:$PYTHONPATH hg unknowncommand > /dev/null
  hg: unknown command 'unknowncommand'
  (use 'hg help' for a list of commands)
  [255]

  $ cd ..