contrib/debugshell.py

dirstate: make writing in-memory changes aware of transaction activity

This patch delays writing in-memory changes out, if transaction is
running.

'_getfsnow()' is defined as a function, to hook it easily for
ambiguous timestamp tests (see also fakedirstatewritetime.py)

'if tr:' code path in this patch is still disabled at this revision,
because there is no client invoking 'dirstate.write()' with repo
object.

BTW, this patch changes 'dirstate.invalidate()' semantics around
'dirstate.write()' in a transaction scope:

  before:
    with repo.transaction():
        dirstate.CHANGE('A')
        dirstate.write() # change for A is written out here
        dirstate.CHANGE('B')
        dirstate.invalidate() # discards only change for B

  after:
    with repo.transaction():
        dirstate.CHANGE('A')
        dirstate.write() # change for A is still kept in memory
        dirstate.CHANGE('B')
        dirstate.invalidate() # discards changes for A and B

Fortunately, there is no code path expecting the former, at least, in
Mercurial itself, because 'dirstateguard' was introduced to remove
such 'dirstate.invalidate()'.

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

import sys
import mercurial
import code
from mercurial import cmdutil

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

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

    code.interact(msg, local=objects)

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

    cl = repo.changelog
    mf = repo.manifest
    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:
        __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)