tests/test-ancestor.py

rebase: improve error message for --base being empty or causing emptiness

Before it just said 'nothing to rebase'.

Now 'if "base" is an empty set:
  abort: empty "base" revision set - can't compute rebase set

If the set of changesets to rebase can't be found from "base", it will fail as
before but with more explanation of what the problem was.

The name of the "base" option is not obvious - it is more like "samples
identifying the branch to rebase". The error messages for problems with the
specified "base" value will use that term and might thus also not be obvious,
but at least they are consistent with the option name. The name "base" will not
be used if the base only was specified implicitly as the working directory
parent.

from mercurial import ancestor, commands, hg, ui, util

# graph is a dict of child->parent adjacency lists for this graph:
# o  13
# |
# | o  12
# | |
# | | o    11
# | | |\
# | | | | o  10
# | | | | |
# | o---+ |  9
# | | | | |
# o | | | |  8
#  / / / /
# | | o |  7
# | | | |
# o---+ |  6
#  / / /
# | | o  5
# | |/
# | o  4
# | |
# o |  3
# | |
# | o  2
# |/
# o  1
# |
# o  0

graph = {0: [-1], 1: [0], 2: [1], 3: [1], 4: [2], 5: [4], 6: [4],
         7: [4], 8: [-1], 9: [6, 7], 10: [5], 11: [3, 7], 12: [9],
         13: [8]}
pfunc = graph.get

class mockchangelog(object):
    parentrevs = graph.get

def runmissingancestors(revs, bases):
    print "%% ancestors of %s and not of %s" % (revs, bases)
    print ancestor.missingancestors(revs, bases, pfunc)

def test_missingancestors():
    # Empty revs
    runmissingancestors([], [1])
    runmissingancestors([], [])

    # If bases is empty, it's the same as if it were [nullrev]
    runmissingancestors([12], [])

    # Trivial case: revs == bases
    runmissingancestors([0], [0])
    runmissingancestors([4, 5, 6], [6, 5, 4])

    # With nullrev
    runmissingancestors([-1], [12])
    runmissingancestors([12], [-1])

    # 9 is a parent of 12. 7 is a parent of 9, so an ancestor of 12. 6 is an
    # ancestor of 12 but not of 7.
    runmissingancestors([12], [9])
    runmissingancestors([9], [12])
    runmissingancestors([12, 9], [7])
    runmissingancestors([7, 6], [12])

    # More complex cases
    runmissingancestors([10], [11, 12])
    runmissingancestors([11], [10])
    runmissingancestors([11], [10, 12])
    runmissingancestors([12], [10])
    runmissingancestors([12], [11])
    runmissingancestors([10, 11, 12], [13])
    runmissingancestors([13], [10, 11, 12])

def genlazyancestors(revs, stoprev=0, inclusive=False):
    print ("%% lazy ancestor set for %s, stoprev = %s, inclusive = %s" %
           (revs, stoprev, inclusive))
    return ancestor.lazyancestors(mockchangelog, revs, stoprev=stoprev,
                                  inclusive=inclusive)

def printlazyancestors(s, l):
    print [n for n in l if n in s]

def test_lazyancestors():
    # Empty revs
    s = genlazyancestors([])
    printlazyancestors(s, [3, 0, -1])

    # Standard example
    s = genlazyancestors([11, 13])
    printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])

    # Including revs
    s = genlazyancestors([11, 13], inclusive=True)
    printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])

    # Test with stoprev
    s = genlazyancestors([11, 13], stoprev=6)
    printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])
    s = genlazyancestors([11, 13], stoprev=6, inclusive=True)
    printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])


# The C gca algorithm requires a real repo. These are textual descriptions of
# dags that have been known to be problematic.
dagtests = [
    '+2*2*2/*3/2',
    '+3*3/*2*2/*4*4/*4/2*4/2*2',
]
def test_gca():
    u = ui.ui()
    for i, dag in enumerate(dagtests):
        repo = hg.repository(u, 'gca%d' % i, create=1)
        cl = repo.changelog
        if not util.safehasattr(cl.index, 'ancestors'):
            # C version not available
            return

        commands.debugbuilddag(u, repo, dag)
        # Compare the results of the Python and C versions. This does not
        # include choosing a winner when more than one gca exists -- we make
        # sure both return exactly the same set of gcas.
        for a in cl:
            for b in cl:
                cgcas = sorted(cl.index.ancestors(a, b))
                pygcas = sorted(ancestor.ancestors(cl.parentrevs, a, b))
                if cgcas != pygcas:
                    print "test_gca: for dag %s, gcas for %d, %d:" % (dag, a, b)
                    print "  C returned:      %s" % cgcas
                    print "  Python returned: %s" % pygcas

if __name__ == '__main__':
    test_missingancestors()
    test_lazyancestors()
    test_gca()