contrib/debugshell.py

tests: fix a test hang on Windows when setting a debuglock

I have no idea why, but running the `hg -R auto-upgrade debuglock --set-lock`
command near the end of `test-upgrade-repo.t` hangs the test.  It does
background the process and `killdaemons.py` runs without error, but control
doesn't return to `run-tests.py` until the process is manually killed.  I did
notice that `$!` in MSYS is *not* the PID of the process that got backgrounded,
even when a simple `sleep 60 &` is run in MSYS without the *.t file.  When
`killdaemons.py` is run manually with the PID in ProcessExplorer, the
backgrounded process terminates immediately, and returns control to
`run-tests.py`.

This looks like it would be a race, but the test waits 10s for the lock file to
appear before attempting to kill the process, so there's time.  `hg serve` has a
`--pid-file` option to write the pid to the file, but this is only a debug
command, so I'm not bothering with cluttering the command line.

# debugshell extension
"""a python shell with repo, changelog & manifest objects"""

import code
import mercurial
import sys
from mercurial import (
    demandimport,
    pycompat,
    registrar,
)

cmdtable = {}
command = registrar.command(cmdtable)


def pdb(ui, repo, msg, **opts):
    objects = {
        'mercurial': mercurial,
        'repo': repo,
        'cl': repo.changelog,
        'mf': repo.manifestlog,
    }

    code.interact(msg, local=objects)


def ipdb(ui, repo, msg, **opts):
    import IPython

    cl = repo.changelog
    mf = repo.manifestlog
    cl, mf  # use variables to appease pyflakes

    IPython.embed()


@command(b'debugshell|dbsh', [])
def debugshell(ui, repo, **opts):
    bannermsg = "loaded repo : %s\n" "using source: %s" % (
        pycompat.sysstr(repo.root),
        mercurial.__path__[0],
    )

    pdbmap = {'pdb': 'code', 'ipdb': 'IPython'}

    debugger = ui.config(b"ui", b"debugger")
    if not debugger:
        debugger = 'pdb'
    else:
        debugger = pycompat.sysstr(debugger)

    # if IPython doesn't exist, fallback to code.interact
    try:
        with demandimport.deactivated():
            __import__(pdbmap[debugger])
    except ImportError:
        ui.warnnoi18n(
            b"%s debugger specified but %s module was not found\n"
            % (debugger, pdbmap[debugger])
        )
        debugger = b'pdb'

    getattr(sys.modules[__name__], debugger)(ui, repo, bannermsg, **opts)