tests/test-revlog-ancestry.py

patch: support diff data loss detection and upgrade

In worst case, generating diff in upgrade mode can be two times more expensive
than generating it in git mode directly: we may have to regenerate the whole
diff again whenever a git feature is detected. Also, the first diff attempt is
completely buffered instead of being streamed. That said, even without having
profiled it yet, I am convinced we can fast-path the upgrade mode if necessary
were it to be used in regular diff commands, and not only in mq where avoiding
data loss is worth the price.

import os
from mercurial import hg, ui, merge

u = ui.ui()

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

def commit(text, time):
    repo.commit(text=text, date="%d 0" % time)

def addcommit(name, time):
    f = open(name, 'w')
    f.write('%s\n' % name)
    f.close()
    repo.add([name])
    commit(name, time)

def update(rev):
    merge.update(repo, rev, False, True, False)

def merge_(rev):
    merge.update(repo, rev, True, False, False)

if __name__ == '__main__':
    addcommit("A", 0)
    addcommit("B", 1)

    update(0)
    addcommit("C", 2)

    merge_(1)
    commit("D", 3)

    update(2)
    addcommit("E", 4)
    addcommit("F", 5)

    update(3)
    addcommit("G", 6)

    merge_(5)
    commit("H", 7)

    update(5)
    addcommit("I", 8)

    # Ancestors
    print 'Ancestors of 5'
    for r in repo.changelog.ancestors(5):
        print r,

    print '\nAncestors of 6 and 5'
    for r in repo.changelog.ancestors(6, 5):
        print r,

    print '\nAncestors of 5 and 4'
    for r in repo.changelog.ancestors(5, 4):
        print r,

    # Descendants
    print '\n\nDescendants of 5'
    for r in repo.changelog.descendants(5):
        print r,

    print '\nDescendants of 5 and 3'
    for r in repo.changelog.descendants(5, 3):
        print r,

    print '\nDescendants of 5 and 4'
    for r in repo.changelog.descendants(5, 4):
        print r,