contrib/debugshell.py

graphmod: restore generator nature of dagwalker

9966c95b8c4f introduced the ability to walk the DAG
given arbitrary revisions, but changed the behaviour of
it to return a list of all nodes (and create a changectx
for each one) rather than doing it lazily.

This has a pretty significant impact on performance for large
repositories (tested on CPython repo, with output disabled):

  $ time hg glog

  real	0m2.642s
  user	0m2.560s
  sys	0m0.080s

Before 9966c95b8c4f:

  $ time hg glog

  real	0m0.143s
  user	0m0.112s
  sys	0m0.032s

And after this fix:

  $ time hg glog

  real	0m0.213s
  user	0m0.184s
  sys	0m0.028s

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

import mercurial
import code

def debugshell(ui, repo, **opts):
    objects = {
        'mercurial': mercurial,
        'repo': repo,
        'cl': repo.changelog,
        'mf': repo.manifest,
    }
    bannermsg = "loaded repo : %s\n" \
                "using source: %s" % (repo.root,
                                      mercurial.__path__[0])
    code.interact(bannermsg, local=objects)

cmdtable = {
    "debugshell|dbsh": (debugshell, [])
}