# destutil.py - Mercurial utility function for command destination

#

#  Copyright Olivia Mackall <olivia@selenic.com> and other

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from .i18n import _

from . import bookmarks, error, obsutil, scmutil, stack

def orphanpossibledestination(repo, rev):

    """Return all changesets that may be a new parent for orphan `rev`.

    This function works fine on non-orphan revisions, it's just silly

    because there's no destination implied by obsolete markers, so

    it'll return nothing.

    """

    tonode = repo.changelog.node

    parents = repo.changelog.parentrevs

    torev = repo.changelog.rev

    dest = set()

    tovisit = list(parents(rev))

    while tovisit:

        r = tovisit.pop()

        succsets = obsutil.successorssets(repo, tonode(r))

        if not succsets:

            # if there are no successors for r, r was probably pruned

            # and we should walk up to r's parents to try and find

            # some successors.

            tovisit.extend(parents(r))

        else:

            # We should probably pick only one destination from split

            # (case where '1 < len(ss)'), This could be the currently

            # tipmost, but the correct result is less clear when

            # results of the split have been moved such that they

            # reside on multiple branches.

            for ss in succsets:

                for n in ss:

                    dr = torev(n)

                    if dr != -1:

                        dest.add(dr)

    return dest

def _destupdateobs(repo, clean):

    """decide of an update destination from obsolescence markers"""

    node = None

    wc = repo[None]

    p1 = wc.p1()

    movemark = None

    if p1.obsolete() and not p1.children():

        # allow updating to successors

        successors = obsutil.successorssets(repo, p1.node())

        # behavior of certain cases is as follows,

        #

        # divergent changesets: update to highest rev, similar to what

        #     is currently done when there are more than one head

        #     (i.e. 'tip')

        #

        # replaced changesets: same as divergent except we know there

        # is no conflict

        #

        # pruned changeset: update to the closest non-obsolete ancestor,

        # similar to what 'hg prune' currently does

        if successors:

            # flatten the list here handles both divergent (len > 1)

            # and the usual case (len = 1)

            successors = [n for sub in successors for n in sub]

            # get the max revision for the given successors set,

            # i.e. the 'tip' of a set

            node = repo.revs(b'max(%ln)', successors).first()

        else:

            p1 = p1.p1()

            while p1.obsolete():

                p1 = p1.p1()

            node = p1.node()

        if node is not None and bookmarks.isactivewdirparent(repo):

            movemark = repo[b'.'].node()

    return node, movemark, None

def _destupdatebook(repo, clean):

    """decide on an update destination from active bookmark"""

    # we also move the active bookmark, if any

    node = None

    activemark, movemark = bookmarks.calculateupdate(repo.ui, repo)

    if activemark is not None:

        node = repo._bookmarks[activemark]

    return node, movemark, activemark

def _destupdatebranch(repo, clean):

    """decide on an update destination from current branch

    This ignores closed branch heads.

    """

    wc = repo[None]

    movemark = node = None

    currentbranch = wc.branch()

    if clean:

        currentbranch = repo[b'.'].branch()

    if currentbranch in repo.branchmap():

        heads = repo.branchheads(currentbranch)

        if heads:

            node = repo.revs(b'max(.::(%ln))', heads).first()

        if bookmarks.isactivewdirparent(repo):

            movemark = repo[b'.'].node()

    elif currentbranch == b'default' and not wc.p1():

        # "null" parent belongs to "default" branch, but it doesn't exist, so

        # update to the tipmost non-closed branch head

        node = repo.revs(b'max(head() and not closed())').first()

    else:

        node = repo[b'.'].node()

    return node, movemark, None

def _destupdatebranchfallback(repo, clean):

    """decide on an update destination from closed heads in current branch"""

    wc = repo[None]

    currentbranch = wc.branch()

    movemark = None

    if currentbranch in repo.branchmap():

        # here, all descendant branch heads are closed

        heads = repo.branchheads(currentbranch, closed=True)

        assert heads, b"any branch has at least one head"

        node = repo.revs(b'max(.::(%ln))', heads).first()

        assert (

            node is not None

        ), b"any revision has at least one descendant branch head"

        if bookmarks.isactivewdirparent(repo):

            movemark = repo[b'.'].node()

    else:

        # here, no "default" branch, and all branches are closed

        node = repo.lookup(b'tip')

        assert node is not None, b"'tip' exists even in empty repository"

    return node, movemark, None

# order in which each step should be evaluated

# steps are run until one finds a destination

destupdatesteps = [b'evolution', b'bookmark', b'branch', b'branchfallback']

# mapping to ease extension overriding steps.

destupdatestepmap = {

    b'evolution': _destupdateobs,

    b'bookmark': _destupdatebook,

    b'branch': _destupdatebranch,

    b'branchfallback': _destupdatebranchfallback,

}

def destupdate(repo, clean=False):

    """destination for bare update operation

    return (rev, movemark, activemark)

    - rev: the revision to update to,

    - movemark: node to move the active bookmark from

                (cf bookmark.calculate update),

    - activemark: a bookmark to activate at the end of the update.

    """

    node = movemark = activemark = None

    for step in destupdatesteps:

        node, movemark, activemark = destupdatestepmap[step](repo, clean)

        if node is not None:

            break

    rev = repo[node].rev()

    return rev, movemark, activemark

msgdestmerge = {

    # too many matching divergent bookmark

    b'toomanybookmarks': {

        b'merge': (

            _(

                b"multiple matching bookmarks to merge -"

                b" please merge with an explicit rev or bookmark"

            ),

            _(b"run 'hg heads' to see all heads, specify rev with -r"),

        ),

        b'rebase': (

            _(

                b"multiple matching bookmarks to rebase -"

                b" please rebase to an explicit rev or bookmark"

            ),

            _(b"run 'hg heads' to see all heads, specify destination with -d"),

        ),

    },

    # no other matching divergent bookmark

    b'nootherbookmarks': {

        b'merge': (

            _(

                b"no matching bookmark to merge - "

                b"please merge with an explicit rev or bookmark"

            ),

            _(b"run 'hg heads' to see all heads, specify rev with -r"),

        ),

        b'rebase': (

            _(

                b"no matching bookmark to rebase - "

                b"please rebase to an explicit rev or bookmark"

            ),

            _(b"run 'hg heads' to see all heads, specify destination with -d"),

        ),

    },

    # branch have too many unbookmarked heads, no obvious destination

    b'toomanyheads': {

        b'merge': (

            _(b"branch '%s' has %d heads - please merge with an explicit rev"),

            _(b"run 'hg heads .' to see heads, specify rev with -r"),

        ),

        b'rebase': (

            _(b"branch '%s' has %d heads - please rebase to an explicit rev"),

            _(b"run 'hg heads .' to see heads, specify destination with -d"),

        ),

    },

    # branch have no other unbookmarked heads

    b'bookmarkedheads': {

        b'merge': (

            _(b"heads are bookmarked - please merge with an explicit rev"),

            _(b"run 'hg heads' to see all heads, specify rev with -r"),

        ),

        b'rebase': (

            _(b"heads are bookmarked - please rebase to an explicit rev"),

            _(b"run 'hg heads' to see all heads, specify destination with -d"),

        ),

    },

    # branch have just a single heads, but there is other branches

    b'nootherbranchheads': {

        b'merge': (

            _(b"branch '%s' has one head - please merge with an explicit rev"),

            _(b"run 'hg heads' to see all heads, specify rev with -r"),

        ),

        b'rebase': (

            _(b"branch '%s' has one head - please rebase to an explicit rev"),

            _(b"run 'hg heads' to see all heads, specify destination with -d"),

        ),

    },

    # repository have a single head

    b'nootherheads': {

        b'merge': (_(b'nothing to merge'), None),

        b'rebase': (_(b'nothing to rebase'), None),

    },

    # repository have a single head and we are not on it

    b'nootherheadsbehind': {

        b'merge': (_(b'nothing to merge'), _(b"use 'hg update' instead")),

        b'rebase': (_(b'nothing to rebase'), _(b"use 'hg update' instead")),

    },

    # We are not on a head

    b'notatheads': {

        b'merge': (

            _(b'working directory not at a head revision'),

            _(b"use 'hg update' or merge with an explicit revision"),

        ),

        b'rebase': (

            _(b'working directory not at a head revision'),

            _(b"use 'hg update' or rebase to an explicit revision"),

        ),

    },

    b'emptysourceset': {

        b'merge': (_(b'source set is empty'), None),

        b'rebase': (_(b'source set is empty'), None),

    },

    b'multiplebranchessourceset': {

        b'merge': (_(b'source set is rooted in multiple branches'), None),

        b'rebase': (

            _(b'rebaseset is rooted in multiple named branches'),

            _(b'specify an explicit destination with --dest'),

        ),

    },

}

def _destmergebook(repo, action=b'merge', sourceset=None, destspace=None):

    """find merge destination in the active bookmark case"""

    node = None

    bmheads = bookmarks.headsforactive(repo)

    curhead = repo._bookmarks[repo._activebookmark]

    if len(bmheads) == 2:

        if curhead == bmheads[0]:

            node = bmheads[1]

        else:

            node = bmheads[0]

    elif len(bmheads) > 2:

        msg, hint = msgdestmerge[b'toomanybookmarks'][action]

        raise error.ManyMergeDestAbort(msg, hint=hint)

    elif len(bmheads) <= 1:

        msg, hint = msgdestmerge[b'nootherbookmarks'][action]

        raise error.NoMergeDestAbort(msg, hint=hint)

    assert node is not None

    return node

def _destmergebranch(

    repo, action=b'merge', sourceset=None, onheadcheck=True, destspace=None

):

    """find merge destination based on branch heads"""

    node = None

    if sourceset is None:

        sourceset = [repo[repo.dirstate.p1()].rev()]

        branch = repo.dirstate.branch()

    elif not sourceset:

        msg, hint = msgdestmerge[b'emptysourceset'][action]

        raise error.NoMergeDestAbort(msg, hint=hint)

    else:

        branch = None

        for ctx in repo.set(b'roots(%ld::%ld)', sourceset, sourceset):

            if branch is not None and ctx.branch() != branch:

                msg, hint = msgdestmerge[b'multiplebranchessourceset'][action]

                raise error.ManyMergeDestAbort(msg, hint=hint)

            branch = ctx.branch()

    bheads = repo.branchheads(branch)

    onhead = repo.revs(b'%ld and %ln', sourceset, bheads)

    if onheadcheck and not onhead:

        # Case A: working copy if not on a head. (merge only)

        #

        # This is probably a user mistake We bailout pointing at 'hg update'

        if len(repo.heads()) <= 1:

            msg, hint = msgdestmerge[b'nootherheadsbehind'][action]

        else:

            msg, hint = msgdestmerge[b'notatheads'][action]

        raise error.Abort(msg, hint=hint)

    # remove heads descendants of source from the set

    bheads = list(repo.revs(b'%ln - (%ld::)', bheads, sourceset))

    # filters out bookmarked heads

    nbhs = list(repo.revs(b'%ld - bookmark()', bheads))

    if destspace is not None:

        # restrict search space

        # used in the 'hg pull --rebase' case, see issue 5214.

        nbhs = list(repo.revs(b'%ld and %ld', destspace, nbhs))

    if len(nbhs) > 1:

        # Case B: There is more than 1 other anonymous heads

        #

        # This means that there will be more than 1 candidate. This is

        # ambiguous. We abort asking the user to pick as explicit destination

        # instead.

        msg, hint = msgdestmerge[b'toomanyheads'][action]

        msg %= (branch, len(bheads) + 1)

        raise error.ManyMergeDestAbort(msg, hint=hint)

    elif not nbhs:

        # Case B: There is no other anonymous heads

        #

        # This means that there is no natural candidate to merge with.

        # We abort, with various messages for various cases.

        if bheads:

            msg, hint = msgdestmerge[b'bookmarkedheads'][action]

        elif len(repo.heads()) > 1:

            msg, hint = msgdestmerge[b'nootherbranchheads'][action]

            msg %= branch

        elif not onhead:

            # if 'onheadcheck == False' (rebase case),

            # this was not caught in Case A.

            msg, hint = msgdestmerge[b'nootherheadsbehind'][action]

        else:

            msg, hint = msgdestmerge[b'nootherheads'][action]

        raise error.NoMergeDestAbort(msg, hint=hint)

    else:

        node = nbhs[0]

    assert node is not None

    return node

def destmerge(

    repo, action=b'merge', sourceset=None, onheadcheck=True, destspace=None

):

    """return the default destination for a merge

    (or raise exception about why it can't pick one)