view contrib/debugcmdserver.py @ 38573:050fbd9d103a

test-convert: demonstrate an unstable hash issue for bzr -> hg -> hg

It looks like the manifest value changing is the only difference, but I'm not
sure why it's happening.  I've got a similar divergence in a production repo
that was also converted from bzr and has an octopus merge[1].  Unlike here, the
manifest values for the destination merge commits reflect the initial merge
only, instead of all four merges agreeing like this test.

    $ hg -R src_repo manifest -r 310 --debug | grep file  # octopus fixup merge
    2d8775bc2481bd28ac87038ecdf33e1dbddc80e9 644   file1
    6adb9353a55bb8be76e71382efc724ec3ccf7ed5 644   file2

    $ hg -R src_repo manifest -r 309 --debug | grep file  # first merge
    362e7cb5163153c4989daad1a834871ae849f205 644   file1
    2c65d947191938c3ea616b7ceb7648ff3843261f 644   file2

    $ hg -R dst_repo manifest -r 273 --debug | grep file  # octopus fixup merge
    362e7cb5163153c4989daad1a834871ae849f205 644   file1
    2c65d947191938c3ea616b7ceb7648ff3843261f 644   file2

    $ hg -R dst_repo manifest -r 272 --debug | grep file  # first merge
    362e7cb5163153c4989daad1a834871ae849f205 644   file1
    2c65d947191938c3ea616b7ceb7648ff3843261f 644   file2

This divergence is espcially annoying because unlike changelog differences, I
haven't figured out a way to fix this in code.  The only way I found to work
around it is to convert up to the point of divergence, `hg bundle` the bad
revision in the source, apply it to the destination, add a line to the shamap,
and fire off the conversion again.

But I suspect that there's more to it than just the octopus merge because
I also have a commit in the same repo, done in Mercurial (well after the
conversion) that is exhibiting a similar issue (and it's not a merge commit).
I'm almost positive that it was created with 4.4 or later.  Any ideas?

[1] https://www.mercurial-scm.org/pipermail/mercurial/2018-June/050924.html

#!/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()