view contrib/debugcmdserver.py @ 34852:d45236f3d38e

log: add obsfate by default in changeset printer

Having an obsfate by default in log will be useful for users to understand why
they have obsolete and unstable changesets. Obsfate will only be shown for
obsolete changesets, which only happens if people opt-in to experimental feature.

But when obsolete changeset are visible, it is very useful to understand where
they are. Having it in log could be sufficient for most people, so they don't
have to learn a new command (like obslog which is itself useful in case of
divergences).

For example, when pulling and working directory parent become obsolete:

  $ hg pull
  ...
  working directory parent is obsolete! (f936c1697205)

This message comes from the Evolve extension.

Obsfate would comes handy:

  $ hg log -G
  o  changeset:   2:6f91013c5136
  |  tag:         tip
  |  parent:      0:4ef7b558f3ec
  |  user:        Boris Feld <[e-mail]>
  |  date:        Mon Oct 09 16:00:27 2017 +0200
  |  summary:     A
  |
  | @  changeset:   1:f936c1697205
  |/   user:        Boris Feld <[e-mail]>
  |    date:        Mon Oct 09 16:00:27 2017 +0200
  |    obsfate:     rewritten using amend as 2:6f91013c5136
  |    summary:     -A
  |
  o  changeset:   0:feb4dd822b8c
     user:        Boris Feld <[e-mail]>
     date:        Tue Oct 09 16:00:00 2017 +0200
     summary:     ROOT

And once we update, we don't have an obsolete changeset in the log anymore so
we don't show obsfate anymore, most users won't see obsfate often if they
don't have obsolete changeset often:

  @  changeset:   2:6f91013c5136
  |  tag:         tip
  |  parent:      0:4ef7b558f3ec
  |  user:        Boris Feld <[e-mail]>
  |  date:        Mon Oct 09 16:00:27 2017 +0200
  |  summary:     A
  |
  o  changeset:   0:feb4dd822b8c
     user:        Boris Feld <[e-mail]>
     date:        Tue Oct 09 16:00:00 2017 +0200
     summary:     ROOT

#!/usr/bin/env python
#
# Dumps output generated by Mercurial's command server in a formatted style to a
# given file or stderr if '-' is specified. Output is also written in its raw
# format to stdout.
#
# $ ./hg serve --cmds pipe | ./contrib/debugcmdserver.py -
# o, 52   -> 'capabilities: getencoding runcommand\nencoding: UTF-8'

from __future__ import absolute_import, print_function
import struct
import sys

if len(sys.argv) != 2:
    print('usage: debugcmdserver.py FILE')
    sys.exit(1)

outputfmt = '>cI'
outputfmtsize = struct.calcsize(outputfmt)

if sys.argv[1] == '-':
    log = sys.stderr
else:
    log = open(sys.argv[1], 'a')

def read(size):
    data = sys.stdin.read(size)
    if not data:
        raise EOFError
    sys.stdout.write(data)
    sys.stdout.flush()
    return data

try:
    while True:
        header = read(outputfmtsize)
        channel, length = struct.unpack(outputfmt, header)
        log.write('%s, %-4d' % (channel, length))
        if channel in 'IL':
            log.write(' -> waiting for input\n')
        else:
            data = read(length)
            log.write(' -> %r\n' % data)
        log.flush()
except EOFError:
    pass
finally:
    if log != sys.stderr:
        log.close()