tests/test-context.py

revlog: calculate base revisions iteratively

This is in preparation for generaldelta, where the revlog entry base field is
reinterpreted as the deltaparent. For that reason we also rename the base
function to chainbase.

Without generaldelta, performance is unaffected, but generaldelta will suffer
from this in _addrevision, since delta chains will be walked repeatedly.
A cache has been added to eliminate this problem completely.

import os
from mercurial import hg, ui

u = ui.ui()

repo = hg.repository(u, 'test1', create=1)
os.chdir('test1')

# create 'foo' with fixed time stamp
f = open('foo', 'w')
f.write('foo\n')
f.close()
os.utime('foo', (1000, 1000))

# add+commit 'foo'
repo[None].add(['foo'])
repo.commit(text='commit1', date="0 0")

print "workingfilectx.date =", repo[None]['foo'].date()