hgext/hbisect.py

ssh: add capability detection at startup

Because older servers don't return any output for unknown commands,
it's tricky to add new commands. The approach is this: we add a
"hello" command that reports any interesting capabilities (and other
things that might be of interest in the future). To detect whether
this new command is supported, we issue both it and our startup
detection command ("between") at the beginning of a connection.

# bisect extension for mercurial
#
# Copyright 2005, 2006 Benoit Boissinot <[e-mail]>
# Inspired by git bisect, extension skeleton taken from mq.py.
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

from mercurial.i18n import gettext as _
from mercurial.demandload import demandload
demandload(globals(), "os sys sets mercurial:hg,util,commands")

versionstr = "0.0.3"

def lookup_rev(ui, repo, rev=None):
    """returns rev or the checked-out revision if rev is None"""
    if not rev is None:
        return repo.lookup(rev)
    parents = [p for p in repo.dirstate.parents() if p != hg.nullid]
    if len(parents) != 1:
        raise util.Abort(_("unexpected number of parents, "
                           "please commit or revert"))
    return parents.pop()

def check_clean(ui, repo):
        modified, added, removed, deleted, unknown = repo.changes()
        if modified or added or removed:
            ui.warn("Repository is not clean, please commit or revert\n")
            sys.exit(1)

class bisect(object):
    """dichotomic search in the DAG of changesets"""
    def __init__(self, ui, repo):
        self.repo = repo
        self.path = repo.join("bisect")
        self.opener = util.opener(self.path)
        self.ui = ui
        self.goodrevs = []
        self.badrev = None
        self.good_dirty = 0
        self.bad_dirty = 0
        self.good_path = "good"
        self.bad_path = "bad"

        if os.path.exists(os.path.join(self.path, self.good_path)):
            self.goodrevs = self.opener(self.good_path).read().splitlines()
            self.goodrevs = [hg.bin(x) for x in self.goodrevs]
        if os.path.exists(os.path.join(self.path, self.bad_path)):
            r = self.opener(self.bad_path).read().splitlines()
            if r:
                self.badrev = hg.bin(r.pop(0))

    def __del__(self):
        if not os.path.isdir(self.path):
            return
        f = self.opener(self.good_path, "w")
        f.write("\n".join([hg.hex(r) for r in  self.goodrevs]))
        if len(self.goodrevs) > 0:
            f.write("\n")
        f = self.opener(self.bad_path, "w")
        if self.badrev:
            f.write(hg.hex(self.badrev) + "\n")

    def init(self):
        """start a new bisection"""
        if os.path.isdir(self.path):
            raise util.Abort(_("bisect directory already exists\n"))
        os.mkdir(self.path)
        check_clean(self.ui, self.repo)
        return 0

    def reset(self):
        """finish a bisection"""
        if os.path.isdir(self.path):
            sl = [os.path.join(self.path, p)
                  for p in [self.bad_path, self.good_path]]
            for s in sl:
                if os.path.exists(s):
                    os.unlink(s)
            os.rmdir(self.path)
        # Not sure about this
        #self.ui.write("Going back to tip\n")
        #self.repo.update(self.repo.changelog.tip())
        return 1

    def num_ancestors(self, head=None, stop=None):
        """
        returns a dict with the mapping:
        node -> number of ancestors (self included)
        for all nodes who are ancestor of head and
        not in stop.
        """
        if head is None:
            head = self.badrev
        return self.__ancestors_and_nb_ancestors(head, stop)[1]

    def ancestors(self, head=None, stop=None):
        """
        returns the set of the ancestors of head (self included)
        who are not in stop.
        """
        if head is None:
            head = self.badrev
        return self.__ancestors_and_nb_ancestors(head, stop)[0]

    def __ancestors_and_nb_ancestors(self, head, stop=None):
        """
        if stop is None then ancestors of goodrevs are used as
        lower limit.

        returns (anc, n_child) where anc is the set of the ancestors of head
        and n_child is a dictionary with the following mapping:
        node -> number of ancestors (self included)
        """
        cl = self.repo.changelog
        if not stop:
            stop = sets.Set([])
            for i in xrange(len(self.goodrevs)-1, -1, -1):
                g = self.goodrevs[i]
                if g in stop:
                    continue
                stop.update(cl.reachable(g))
        def num_children(a):
            """
            returns a dictionnary with the following mapping
            node -> [number of children, empty set]
            """
            d = {a: [0, sets.Set([])]}
            for i in xrange(cl.rev(a)+1):
                n = cl.node(i)
                if not d.has_key(n):
                    d[n] = [0, sets.Set([])]
                parents = [p for p in cl.parents(n) if p != hg.nullid]
                for p in parents:
                    d[p][0] += 1
            return d

        if head in stop:
            raise util.Abort(_("Unconsistent state, %s:%s is good and bad")
                             % (cl.rev(head), hg.short(head)))
        n_child = num_children(head)
        for i in xrange(cl.rev(head)+1):
            n = cl.node(i)
            parents = [p for p in cl.parents(n) if p != hg.nullid]
            for p in parents:
                n_child[p][0] -= 1
                if not n in stop:
                    n_child[n][1].union_update(n_child[p][1])
                if n_child[p][0] == 0:
                    n_child[p] = len(n_child[p][1])
            if not n in stop:
                n_child[n][1].add(n)
            if n_child[n][0] == 0:
                if n == head:
                    anc = n_child[n][1]
                n_child[n] = len(n_child[n][1])
        return anc, n_child

    def next(self):
        if not self.badrev:
            raise util.Abort(_("You should give at least one bad revision"))
        if not self.goodrevs:
            self.ui.warn(_("No good revision given\n"))
            self.ui.warn(_("Marking the first revision as good\n"))
        ancestors, num_ancestors = self.__ancestors_and_nb_ancestors(
                                    self.badrev)
        tot = len(ancestors)
        if tot == 1:
            if ancestors.pop() != self.badrev:
                raise util.Abort(_("Could not find the first bad revision"))
            self.ui.write(_("The first bad revision is:\n"))
            displayer = commands.show_changeset(self.ui, self.repo, {})
            displayer.show(changenode=self.badrev)
            return None
        best_rev = None
        best_len = -1
        for n in ancestors:
            l = num_ancestors[n]
            l = min(l, tot - l)
            if l > best_len:
                best_len = l
                best_rev = n
        assert best_rev is not None
        nb_tests = 0
        q, r = divmod(tot, 2)
        while q:
            nb_tests += 1
            q, r = divmod(q, 2)
        msg = _("Testing changeset %s:%s (%s changesets remaining, "
                "~%s tests)\n") % (self.repo.changelog.rev(best_rev),
                                   hg.short(best_rev), tot, nb_tests)
        self.ui.write(msg)
        return best_rev

    def autonext(self):
        """find and update to the next revision to test"""
        check_clean(self.ui, self.repo)
        rev = self.next()
        if rev is not None:
            return self.repo.update(rev, force=True)

    def good(self, rev):
        self.goodrevs.append(rev)

    def autogood(self, rev=None):
        """mark revision as good and update to the next revision to test"""
        check_clean(self.ui, self.repo)
        rev = lookup_rev(self.ui, self.repo, rev)
        self.good(rev)
        if self.badrev:
            return self.autonext()

    def bad(self, rev):
        self.badrev = rev

    def autobad(self, rev=None):
        """mark revision as bad and update to the next revision to test"""
        check_clean(self.ui, self.repo)
        rev = lookup_rev(self.ui, self.repo, rev)
        self.bad(rev)
        if self.goodrevs:
            self.autonext()

# should we put it in the class ?
def test(ui, repo, rev):
    """test the bisection code"""
    b = bisect(ui, repo)
    rev = repo.lookup(rev)
    ui.write("testing with rev %s\n" % hg.hex(rev))
    anc = b.ancestors()
    while len(anc) > 1:
        if not rev in anc:
            ui.warn("failure while bisecting\n")
            sys.exit(1)
        ui.write("it worked :)\n")
        new_rev = b.next()
        ui.write("choosing if good or bad\n")
        if rev in b.ancestors(head=new_rev):
            b.bad(new_rev)
            ui.write("it is bad\n")
        else:
            b.good(new_rev)
            ui.write("it is good\n")
        anc = b.ancestors()
        #repo.update(new_rev, force=True)
    for v in anc:
        if v != rev:
            ui.warn("fail to found cset! :(\n")
            return 1
    ui.write("Found bad cset: %s\n" % hg.hex(b.badrev))
    ui.write("Everything is ok :)\n")
    return 0

def bisect_run(ui, repo, cmd=None, *args):
    """bisect extension: dichotomic search in the DAG of changesets
for subcommands see "hg bisect help\"
    """
    def help_(cmd=None, *args):
        """show help for a given bisect subcommand or all subcommands"""
        cmdtable = bisectcmdtable
        if cmd:
            doc = cmdtable[cmd][0].__doc__
            synopsis = cmdtable[cmd][2]
            ui.write(synopsis + "\n")
            ui.write("\n" + doc + "\n")
            return
        ui.write(_("list of subcommands for the bisect extension\n\n"))
        cmds = cmdtable.keys()
        cmds.sort()
        m = max([len(c) for c in cmds])
        for cmd in cmds:
            doc = cmdtable[cmd][0].__doc__.splitlines(0)[0].rstrip()
            ui.write(" %-*s   %s\n" % (m, cmd, doc))

    b = bisect(ui, repo)
    bisectcmdtable = {
        "init": (b.init, 0, _("hg bisect init")),
        "bad": (b.autobad, 1, _("hg bisect bad [<rev>]")),
        "good": (b.autogood, 1, _("hg bisect good [<rev>]")),
        "next": (b.autonext, 0, _("hg bisect next")),
        "reset": (b.reset, 0, _("hg bisect reset")),
        "help": (help_, 1, _("hg bisect help [<subcommand>]")),
    }

    if not bisectcmdtable.has_key(cmd):
        ui.warn(_("bisect: Unknown sub-command\n"))
        return help_()
    if len(args) > bisectcmdtable[cmd][1]:
        ui.warn(_("bisect: Too many arguments\n"))
        return help_()
    return bisectcmdtable[cmd][0](*args)

cmdtable = {
    "bisect": (bisect_run, [], _("hg bisect [help|init|reset|next|good|bad]")),
    #"bisect-test": (test, [], "hg bisect-test rev"),
}