view hgext3rd/topic/evolvebits.py @ 6889:a66cf9008781

obslog: also display patch for rebased changesets

This applies the same logic that is used for "merge-diff" to rebased
changesets. The successors' content is compared to the content of the
predecessors rebased in-memory on the new parents.

This highlights the changes that were actually introduced while rebasing (like
conflict resolution or API adjustment).

As a side effect, obslog now also outputs slightly more diffs for splits,
showing what parts of the original big changeset were moved to the smaller
split components (but for now it only works for the first few changesets).

import collections

from mercurial import (
    obsutil,
)

# Copied from evolve 081605c2e9b6

def builddependencies(repo, revs):
    """returns dependency graphs giving an order to solve instability of revs
    (see _orderrevs for more information on usage)"""

    # For each troubled revision we keep track of what instability if any should
    # be resolved in order to resolve it. Example:
    # dependencies = {3: [6], 6:[]}
    # Means that: 6 has no dependency, 3 depends on 6 to be solved
    dependencies = {}
    # rdependencies is the inverted dict of dependencies
    rdependencies = collections.defaultdict(set)

    for r in revs:
        dependencies[r] = set()
        for p in repo[r].parents():
            try:
                succ = _singlesuccessor(repo, p)
            except MultipleSuccessorsError as exc:
                dependencies[r] = exc.successorssets
                continue
            if succ in revs:
                dependencies[r].add(succ)
                rdependencies[succ].add(r)
    return dependencies, rdependencies

def _singlesuccessor(repo, p):
    """returns p (as rev) if not obsolete or its unique latest successors

    fail if there are no such successor"""

    if not p.obsolete():
        return p.rev()
    obs = repo[p]
    ui = repo.ui
    cache = {}
    newer = obsutil.successorssets(repo, obs.node(), cache=cache)
    # search of a parent which is not killed
    while not newer:
        ui.debug(b"stabilize target %s is plain dead,"
                 b" trying to stabilize on its parent\n" %
                 obs)
        obs = obs.p1()
        newer = obsutil.successorssets(repo, obs.node(), cache=cache)
    if 1 < len(newer):
        # divergence case
        # we should pick as arbitrary one
        raise MultipleSuccessorsError(newer)
    elif 1 < len(newer[0]):
        splitheads = list(repo.revs(b'heads(%ln::%ln)', newer[0], newer[0]))
        if 1 < len(splitheads):
            # split case, See if we can make sense of it.
            raise MultipleSuccessorsError(newer)
        return splitheads[0]

    return repo[newer[0][0]].rev()

class MultipleSuccessorsError(RuntimeError):
    """Exception raised by _singlesuccessor when multiple successor sets exists

    The object contains the list of successorssets in its 'successorssets'
    attribute to call to easily recover.
    """

    def __init__(self, successorssets):
        self.successorssets = successorssets