contrib/debugshell.py

run-tests: cache hghave results

Spawning a process on Windows is expensive.  I've got a version of
test-lfs-test-server.t locally which prints the http request/responses that
totals 819 lines, with 149 conditional lines, 11 #if tests, and 2 test cases.
It takes just under 1 minute with this change to run both cases, vs just over
2 minutes without this change.  Worse, when I explored adding ui.debug to the
test, it takes 13 minutes due to all of the mismatches and retests, vs less than
1 minute with this change.  Overall, the difference when running all tests is
negligible- 103 minutes with this change, vs 105 without when using -j9.

It also looks like an exit value of 2 from `hghave` is treated specially, but
there's nothing preventing 2 missing features from also using this value.

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

from __future__ import absolute_import
import code
import mercurial
import sys
from mercurial import (
    demandimport,
    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('debugshell|dbsh', [])
def debugshell(ui, repo, **opts):
    bannermsg = "loaded repo : %s\n" \
                "using source: %s" % (repo.root,
                                      mercurial.__path__[0])

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

    debugger = ui.config("ui", "debugger")
    if not debugger:
        debugger = 'pdb'

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

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