view hgext3rd/topic/stack.py @ 2939:7759d040d48d

topic: provide more information when behind count cannot be computed

The behind count has been confusing for various user and the associated error
message is even worth. We try to clarify it to see if that helps.

# stack.py - code related to stack workflow
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from mercurial.i18n import _
from mercurial import (
    destutil,
    context,
    error,
    node,
    phases,
    util,
)
from .evolvebits import builddependencies, _singlesuccessor

short = node.short

# TODO: compat

if not util.safehasattr(context.basectx, 'orphan'):
    context.basectx.orphan = context.basectx.unstable

if not util.safehasattr(context.basectx, 'isunstable'):
    context.basectx.isunstable = context.basectx.troubled

class stack(object):
    """object represent a stack and common logic associated to it."""

    def __init__(self, repo, branch=None, topic=None):
        self._repo = repo
        self.branch = branch
        self.topic = topic
        self.behinderror = None
        if topic is not None and branch is not None:
            raise error.ProgrammingError('both branch and topic specified (not defined yet)')
        elif topic is not None:
            trevs = repo.revs("topic(%s) - obsolete()", topic)
        elif branch is not None:
            trevs = repo.revs("branch(%s) - public() - obsolete() - topic()", branch)
        else:
            raise error.ProgrammingError('neither branch and topic specified (not defined yet)')
        self._revs = trevs

    def __iter__(self):
        return iter(self.revs)

    def __getitem__(self, index):
        return self.revs[index]

    def index(self, item):
        return self.revs.index(item)

    @util.propertycache
    def _dependencies(self):
        deps, rdeps = builddependencies(self._repo, self._revs)

        repo = self._repo
        srcpfunc = repo.changelog.parentrevs

        ### post process to skip over possible gaps in the stack
        #
        # For example in the following situation, we need to detect that "t3"
        # indirectly depends on t2.
        #
        #  o t3
        #  |
        #  o other
        #  |
        #  o t2
        #  |
        #  o t1

        pmap = {}

        def pfuncrev(repo, rev):
            """a special "parent func" that also consider successors"""
            parents = pmap.get(rev)
            if parents is None:
                parents = [repo[_singlesuccessor(repo, repo[p])].rev()
                           for p in srcpfunc(rev) if 0 <= p]
                pmap[rev] = parents
            return parents

        revs = self._revs
        stackrevs = set(self._revs)
        for root in [r for r in revs if not deps[r]]:
            seen = set()
            stack = [root]
            while stack:
                current = stack.pop()
                for p in pfuncrev(repo, current):
                    if p in seen:
                        continue
                    seen.add(p)
                    if p in stackrevs:
                        rdeps[p].add(root)
                        deps[root].add(p)
                    elif phases.public < repo[p].phase():
                        # traverse only if we did not found a proper candidate
                        stack.append(p)

        return deps, rdeps

    @util.propertycache
    def revs(self):
        # some duplication/change from _orderrevs because we use a post
        # processed dependency graph.

        # Step 1: compute relation of revision with each other
        dependencies, rdependencies = self._dependencies
        dependencies = dependencies.copy()
        rdependencies = rdependencies.copy()
        # Step 2: Build the ordering
        # Remove the revisions with no dependency(A) and add them to the ordering.
        # Removing these revisions leads to new revisions with no dependency (the
        # one depending on A) that we can remove from the dependency graph and add
        # to the ordering. We progress in a similar fashion until the ordering is
        # built
        solvablerevs = [r for r in sorted(dependencies.keys())
                        if not dependencies[r]]
        revs = []
        while solvablerevs:
            rev = solvablerevs.pop()
            for dependent in rdependencies[rev]:
                dependencies[dependent].remove(rev)
                if not dependencies[dependent]:
                    solvablerevs.append(dependent)
            del dependencies[rev]
            revs.append(rev)

        revs.extend(sorted(dependencies))
        # step 3: add t0
        if revs:
            pt1 = self._repo[revs[0]].p1()
        else:
            pt1 = self._repo['.']

        if pt1.obsolete():
            pt1 = self._repo[_singlesuccessor(self._repo, pt1)]
        revs.insert(0, pt1.rev())
        return revs

    @util.propertycache
    def changesetcount(self):
        return len(self._revs)

    @util.propertycache
    def troubledcount(self):
        return len([r for r in self._revs if self._repo[r].isunstable()])

    @util.propertycache
    def heads(self):
        revs = self.revs[1:]
        deps, rdeps = self._dependencies
        return [r for r in revs if not rdeps[r]]

    @util.propertycache
    def behindcount(self):
        revs = self.revs[1:]
        deps, rdeps = self._dependencies
        if revs:
            minroot = [min(r for r in revs if not deps[r])]
            try:
                dest = destutil.destmerge(self._repo, action='rebase',
                                          sourceset=minroot,
                                          onheadcheck=False)
                return len(self._repo.revs("only(%d, %ld)", dest, minroot))
            except error.NoMergeDestAbort:
                return 0
            except error.ManyMergeDestAbort as exc:
                # XXX we should make it easier for upstream to provide the information
                self.behinderror = str(exc).split('-', 1)[0].rstrip()
                return -1
        return 0

    @util.propertycache
    def branches(self):
        branches = sorted(set(self._repo[r].branch() for r in self._revs))
        if not branches:
            branches = set([self._repo[None].branch()])
        return branches

def labelsgen(prefix, labelssuffix):
    """ Takes a label prefix and a list of suffixes. Returns a string of the prefix
    formatted with each suffix separated with a space.
    """
    return ' '.join(prefix % suffix for suffix in labelssuffix)

def showstack(ui, repo, branch=None, topic=None, opts=None):
    if opts is None:
        opts = {}

    if topic is not None and branch is not None:
        msg = 'both branch and topic specified [%s]{%s}(not defined yet)'
        msg %= (branch, topic)
        raise error.ProgrammingError(msg)
    elif topic is not None:
        prefix = 't'
        if topic not in repo.topics:
            raise error.Abort(_('cannot resolve "%s": no such topic found') % topic)
    elif branch is not None:
        prefix = 'b'
    else:
        raise error.ProgrammingError('neither branch and topic specified (not defined yet)')

    fm = ui.formatter('topicstack', opts)
    prev = None
    entries = []
    idxmap = {}

    label = 'topic'
    if topic == repo.currenttopic:
        label = 'topic.active'

    data = stackdata(repo, branch=branch, topic=topic)
    empty = False
    if data['changesetcount'] == 0:
        empty = True
    if topic is not None:
        fm.plain(_('### topic: %s')
                 % ui.label(topic, label),
                 label='topic.stack.summary.topic')

        if 1 < data['headcount']:
            fm.plain(' (')
            fm.plain('%d heads' % data['headcount'],
                     label='topic.stack.summary.headcount.multiple')
            fm.plain(')')
        fm.plain('\n')
    fm.plain(_('### branch: %s')
             % '+'.join(data['branches']), # XXX handle multi branches
             label='topic.stack.summary.branches')
    if topic is None:
        if 1 < data['headcount']:
            fm.plain(' (')
            fm.plain('%d heads' % data['headcount'],
                     label='topic.stack.summary.headcount.multiple')
            fm.plain(')')
    else:
        if data['behindcount'] == -1:
            fm.plain(', ')
            fm.plain('ambigious rebase destination - %s' % data['behinderror'],
                     label='topic.stack.summary.behinderror')
        elif data['behindcount']:
            fm.plain(', ')
            fm.plain('%d behind' % data['behindcount'], label='topic.stack.summary.behindcount')
    fm.plain('\n')

    if empty:
        fm.plain(_("(stack is empty)\n"))

    for idx, r in enumerate(stack(repo, branch=branch, topic=topic), 0):
        ctx = repo[r]
        # special case for t0, b0 as it's hard to plugin into rest of the logic
        if idx == 0:
            # t0, b0 can be None
            if r == -1:
                continue
            entries.append((idx, False, ctx))
            prev = ctx.rev()
            continue
        p1 = ctx.p1()
        p2 = ctx.p2()
        if p1.obsolete():
            p1 = repo[_singlesuccessor(repo, p1)]
        if p2.node() != node.nullid:
            entries.append((idxmap.get(p1.rev()), False, p1))
            entries.append((idxmap.get(p2.rev()), False, p2))
        elif p1.rev() != prev and p1.node() != node.nullid:
            entries.append((idxmap.get(p1.rev()), False, p1))
        entries.append((idx, True, ctx))
        idxmap[ctx.rev()] = idx
        prev = r

    # super crude initial version
    for idx, isentry, ctx in entries[::-1]:

        states = []
        iscurrentrevision = repo.revs('%d and parents()', ctx.rev())

        if not isentry:
            symbol = '^'
            # "base" is kind of a "ghost" entry
            # skip other label for them (no current, no unstable)
            states = ['base']
        elif ctx.orphan():
            # current revision can be unstable also, so in that case show both
            # the states and the symbol '@' (issue5553)
            if iscurrentrevision:
                states.append('current')
                symbol = '@'
            symbol = '$'
            states.append('unstable')
        elif iscurrentrevision:
            states.append('current')
            symbol = '@'
        else:
            symbol = ':'
            states.append('clean')
        fm.startitem()
        fm.data(isentry=isentry)

        if idx is None:
            fm.plain('  ')
            if ui.verbose:
                fm.plain('              ')
        else:
            fm.write('topic.stack.index', '%s%%d' % prefix, idx,
                     label='topic.stack.index ' + labelsgen('topic.stack.index.%s', states))
            if ui.verbose:
                fm.write('topic.stack.shortnode', '(%s)', short(ctx.node()),
                         label='topic.stack.shortnode ' + labelsgen('topic.stack.shortnode.%s', states))
        fm.write('topic.stack.state.symbol', '%s', symbol,
                 label='topic.stack.state ' + labelsgen('topic.stack.state.%s', states))
        fm.plain(' ')
        fm.write('topic.stack.desc', '%s', ctx.description().splitlines()[0],
                 label='topic.stack.desc ' + labelsgen('topic.stack.desc.%s', states))
        fm.condwrite(states != ['clean'] and idx is not None, 'topic.stack.state',
                     ' (%s)', fm.formatlist(states, 'topic.stack.state'),
                     label='topic.stack.state ' + labelsgen('topic.stack.state.%s', states))
        fm.plain('\n')
    fm.end()

def stackdata(repo, branch=None, topic=None):
    """get various data about a stack

    :changesetcount: number of non-obsolete changesets in the stack
    :troubledcount: number on troubled changesets
    :headcount: number of heads on the topic
    :behindcount: number of changeset on rebase destination
    """
    data = {}
    current = stack(repo, branch, topic)
    data['changesetcount'] = current.changesetcount
    data['troubledcount'] = current.troubledcount
    data['headcount'] = len(current.heads)
    data['behindcount'] = current.behindcount
    data['behinderror'] = current.behinderror
    data['branches'] = current.branches
    return data