view tests/test-revlog-ancestry.py @ 44985:1ca0047fd7e1

absorb: preserve changesets which were already empty

Most commands in Mercurial (commit, rebase, absorb itself) don’t create empty
changesets or drop them if they become empty. If there’s a changeset that’s
empty, it must be a deliberate choice of the user. At least it shouldn’t be
absorb’s responsibility to prune them. The fact that changesets that became
empty during absorb are pruned, is unaffected by this.

This case was found while writing patches which make it possible to configure
absorb and rebase to not drop empty changesets. Even without having such config
set, I think it’s valuable to preserve changesets which were already empty.

from __future__ import absolute_import, print_function
import os
from mercurial import (
    hg,
    merge,
    ui as uimod,
)

u = uimod.ui.load()

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


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


def addcommit(name, time):
    f = open(name, 'wb')
    f.write(b'%s\n' % name)
    f.close()
    repo[None].add([name])
    commit(name, time)


def update(rev):
    merge.clean_update(repo[rev])


def merge_(rev):
    merge.merge(repo[rev])


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

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

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

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

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

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

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

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

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

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

    print('\nAncestors of 7, stop at 6')
    for r in repo.changelog.ancestors([7], 6):
        print(r, end=' ')

    print('\nAncestors of 7, including revs')
    for r in repo.changelog.ancestors([7], inclusive=True):
        print(r, end=' ')

    print('\nAncestors of 7, 5 and 3, including revs')
    for r in repo.changelog.ancestors([7, 5, 3], inclusive=True):
        print(r, end=' ')

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

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

    print('\nDescendants of 5 and 4')
    print(*repo.changelog.descendants([5, 4]), sep=' ')