contrib/showstack.py

exchangev2: support for calling rawstorefiledata to retrieve raw files

This is somewhat hacky. For that I apologize.

At the 4.8 Sprint, we decided we wanted to land support in wireprotov2 for doing
a partial clone with changelog and manifestlog bootstrapped from a "stream clone"
like primitive.

This commit implements the client-side bits necessary to facilitate that.

If the new server-side command for obtaining raw files data is available, we
call it to get the raw files for the changelog and manifestlog. Then we
fall through to an incremental pull. But when fetching files data, instead
of using the list of a changesets and manifests that we fetched via the
"changesetdata" command, we do a linear scan of the repo and resolve the
changeset and manifest nodes along with the manifest linkrevs.

Differential Revision: https://phab.mercurial-scm.org/D5135

# showstack.py - extension to dump a Python stack trace on signal
#
# binds to both SIGQUIT (Ctrl-\) and SIGINFO (Ctrl-T on BSDs)
"""dump stack trace when receiving SIGQUIT (Ctrl-\) and SIGINFO (Ctrl-T on BSDs)
"""

from __future__ import absolute_import, print_function
import signal
import sys
import traceback

def sigshow(*args):
    sys.stderr.write("\n")
    traceback.print_stack(args[1], limit=10, file=sys.stderr)
    sys.stderr.write("----\n")

def sigexit(*args):
    sigshow(*args)
    print('alarm!')
    sys.exit(1)

def extsetup(ui):
    signal.signal(signal.SIGQUIT, sigshow)
    signal.signal(signal.SIGALRM, sigexit)
    try:
        signal.signal(signal.SIGINFO, sigshow)
    except AttributeError:
        pass