view mercurial/manifest.py @ 23971:6becb9dbca25 stable

merge: mark .hgsubstate as possibly dirty before submerge for consistency

Before this patch, failure of updating subrepos may cause inconsistent
".hgsubstate". For example:

  1. dirstate entry for ".hgsubstate" of the parent repo is filled
     with valid size/date (via "hg state" or so)

  2. "hg update" is invoked at the parent repo

  3. ".hgsubstate" of the parent repo is updated on the filesystem as
     a part of "g"(et) action in "merge.applyupdates"

  4. it is assumed that size/date of ".hgsubstate" on the filesystem
     aren't changed from ones at (1)

     this is not so difficult condition, because just changing hash
     ids (every ids are same in length) in ".hgsubstate" doesn't
     change the file size of it

  5. "subrepo.submerge()" is invoked to update subrepos

  6. failure of updating in one of subrepos raises exception
     (e.g. "untracked file differs")

  7. "hg update" is aborted without updating dirstate of the parent repo

     dirstate entry for ".hgsubstate" still holds size/date at (1)

Then, ".hgsubstate" of the parent repo is treated as "CLEAN"
unexpectedly, because updating ".hgsubstate" at (3) doesn't change
size/date of it on the filesystem: see assumption at (4).

This inconsistent ".hgsubstate" status causes unexpected behavior, for
example:

  - "hg revert" forgets to revert ".hgsubstate"

  - "hg update" misunderstands that (not yet updated) subrepos diverge
    (then, it shows the prompt to confirm user's decision)

To avoid inconsistent ".hgsubstate" status above, this patch marks
".hgsubstate" as possibly dirty before "submerge" invocation.
"normallookup"-ed (= dirty) dirstate should be written out, even if
processing is aborted by failure.

This patch marks ".hgsubstate" as possibly dirty before "submerge",
also when it is removed or merged while merging, for safety. This
should prevent Mercurial from misunderstanding inconsistent
".hgsubstate" as clean.

To satisfy conditions at (1) and (4) above, this patch uses "hg status
--config debug.dirstate.delaywrite=2" (to fill valid size/date into
dirstate) and "touch" (to fix date of the file).

# manifest.py - manifest revision class for mercurial
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
#
# 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 _
import mdiff, parsers, error, revlog, util
import array, struct

class manifestdict(dict):
    def __init__(self, mapping=None, flags=None):
        if mapping is None:
            mapping = {}
        if flags is None:
            flags = {}
        dict.__init__(self, mapping)
        self._flags = flags
    def __setitem__(self, k, v):
        assert v is not None
        dict.__setitem__(self, k, v)
    def flags(self, f):
        return self._flags.get(f, "")
    def setflag(self, f, flags):
        """Set the flags (symlink, executable) for path f."""
        self._flags[f] = flags
    def copy(self):
        return manifestdict(self, dict.copy(self._flags))
    def intersectfiles(self, files):
        '''make a new manifestdict with the intersection of self with files

        The algorithm assumes that files is much smaller than self.'''
        ret = manifestdict()
        for fn in files:
            if fn in self:
                ret[fn] = self[fn]
                flags = self._flags.get(fn, None)
                if flags:
                    ret._flags[fn] = flags
        return ret

    def matches(self, match):
        '''generate a new manifest filtered by the match argument'''
        if match.always():
            return self.copy()

        files = match.files()
        if (match.matchfn == match.exact or
            (not match.anypats() and util.all(fn in self for fn in files))):
            return self.intersectfiles(files)

        mf = self.copy()
        for fn in mf.keys():
            if not match(fn):
                del mf[fn]
        return mf

    def diff(self, m2, clean=False):
        '''Finds changes between the current manifest and m2.

        Args:
          m2: the manifest to which this manifest should be compared.
          clean: if true, include files unchanged between these manifests
                 with a None value in the returned dictionary.

        The result is returned as a dict with filename as key and
        values of the form ((n1,fl1),(n2,fl2)), where n1/n2 is the
        nodeid in the current/other manifest and fl1/fl2 is the flag
        in the current/other manifest. Where the file does not exist,
        the nodeid will be None and the flags will be the empty
        string.
        '''
        diff = {}

        for fn, n1 in self.iteritems():
            fl1 = self._flags.get(fn, '')
            n2 = m2.get(fn, None)
            fl2 = m2._flags.get(fn, '')
            if n2 is None:
                fl2 = ''
            if n1 != n2 or fl1 != fl2:
                diff[fn] = ((n1, fl1), (n2, fl2))
            elif clean:
                diff[fn] = None

        for fn, n2 in m2.iteritems():
            if fn not in self:
                fl2 = m2._flags.get(fn, '')
                diff[fn] = ((None, ''), (n2, fl2))

        return diff

    def text(self):
        """Get the full data of this manifest as a bytestring."""
        fl = sorted(self)
        _checkforbidden(fl)

        hex, flags = revlog.hex, self.flags
        # if this is changed to support newlines in filenames,
        # be sure to check the templates/ dir again (especially *-raw.tmpl)
        return ''.join("%s\0%s%s\n" % (f, hex(self[f]), flags(f)) for f in fl)

    def fastdelta(self, base, changes):
        """Given a base manifest text as an array.array and a list of changes
        relative to that text, compute a delta that can be used by revlog.
        """
        delta = []
        dstart = None
        dend = None
        dline = [""]
        start = 0
        # zero copy representation of base as a buffer
        addbuf = util.buffer(base)

        # start with a readonly loop that finds the offset of
        # each line and creates the deltas
        for f, todelete in changes:
            # bs will either be the index of the item or the insert point
            start, end = _msearch(addbuf, f, start)
            if not todelete:
                l = "%s\0%s%s\n" % (f, revlog.hex(self[f]), self.flags(f))
            else:
                if start == end:
                    # item we want to delete was not found, error out
                    raise AssertionError(
                            _("failed to remove %s from manifest") % f)
                l = ""
            if dstart is not None and dstart <= start and dend >= start:
                if dend < end:
                    dend = end
                if l:
                    dline.append(l)
            else:
                if dstart is not None:
                    delta.append([dstart, dend, "".join(dline)])
                dstart = start
                dend = end
                dline = [l]

        if dstart is not None:
            delta.append([dstart, dend, "".join(dline)])
        # apply the delta to the base, and get a delta for addrevision
        deltatext, arraytext = _addlistdelta(base, delta)
        return arraytext, deltatext

def _msearch(m, s, lo=0, hi=None):
    '''return a tuple (start, end) that says where to find s within m.

    If the string is found m[start:end] are the line containing
    that string.  If start == end the string was not found and
    they indicate the proper sorted insertion point.

    m should be a buffer or a string
    s is a string'''
    def advance(i, c):
        while i < lenm and m[i] != c:
            i += 1
        return i
    if not s:
        return (lo, lo)
    lenm = len(m)
    if not hi:
        hi = lenm
    while lo < hi:
        mid = (lo + hi) // 2
        start = mid
        while start > 0 and m[start - 1] != '\n':
            start -= 1
        end = advance(start, '\0')
        if m[start:end] < s:
            # we know that after the null there are 40 bytes of sha1
            # this translates to the bisect lo = mid + 1
            lo = advance(end + 40, '\n') + 1
        else:
            # this translates to the bisect hi = mid
            hi = start
    end = advance(lo, '\0')
    found = m[lo:end]
    if s == found:
        # we know that after the null there are 40 bytes of sha1
        end = advance(end + 40, '\n')
        return (lo, end + 1)
    else:
        return (lo, lo)

def _checkforbidden(l):
    """Check filenames for illegal characters."""
    for f in l:
        if '\n' in f or '\r' in f:
            raise error.RevlogError(
                _("'\\n' and '\\r' disallowed in filenames: %r") % f)


# apply the changes collected during the bisect loop to our addlist
# return a delta suitable for addrevision
def _addlistdelta(addlist, x):
    # for large addlist arrays, building a new array is cheaper
    # than repeatedly modifying the existing one
    currentposition = 0
    newaddlist = array.array('c')

    for start, end, content in x:
        newaddlist += addlist[currentposition:start]
        if content:
            newaddlist += array.array('c', content)

        currentposition = end

    newaddlist += addlist[currentposition:]

    deltatext = "".join(struct.pack(">lll", start, end, len(content))
                   + content for start, end, content in x)
    return deltatext, newaddlist

def _parse(lines):
    mfdict = manifestdict()
    parsers.parse_manifest(mfdict, mfdict._flags, lines)
    return mfdict

class manifest(revlog.revlog):
    def __init__(self, opener):
        # we expect to deal with not more than four revs at a time,
        # during a commit --amend
        self._mancache = util.lrucachedict(4)
        revlog.revlog.__init__(self, opener, "00manifest.i")

    def readdelta(self, node):
        r = self.rev(node)
        return _parse(mdiff.patchtext(self.revdiff(self.deltaparent(r), r)))

    def readfast(self, node):
        '''use the faster of readdelta or read'''
        r = self.rev(node)
        deltaparent = self.deltaparent(r)
        if deltaparent != revlog.nullrev and deltaparent in self.parentrevs(r):
            return self.readdelta(node)
        return self.read(node)

    def read(self, node):
        if node == revlog.nullid:
            return manifestdict() # don't upset local cache
        if node in self._mancache:
            return self._mancache[node][0]
        text = self.revision(node)
        arraytext = array.array('c', text)
        mapping = _parse(text)
        self._mancache[node] = (mapping, arraytext)
        return mapping

    def find(self, node, f):
        '''look up entry for a single file efficiently.
        return (node, flags) pair if found, (None, None) if not.'''
        if node in self._mancache:
            mapping = self._mancache[node][0]
            return mapping.get(f), mapping.flags(f)
        text = self.revision(node)
        start, end = _msearch(text, f)
        if start == end:
            return None, None
        l = text[start:end]
        f, n = l.split('\0')
        return revlog.bin(n[:40]), n[40:-1]

    def add(self, map, transaction, link, p1, p2, added, removed):
        if p1 in self._mancache:
            # If our first parent is in the manifest cache, we can
            # compute a delta here using properties we know about the
            # manifest up-front, which may save time later for the
            # revlog layer.

            _checkforbidden(added)
            # combine the changed lists into one list for sorting
            work = [(x, False) for x in added]
            work.extend((x, True) for x in removed)
            # this could use heapq.merge() (from Python 2.6+) or equivalent
            # since the lists are already sorted
            work.sort()

            arraytext, deltatext = map.fastdelta(self._mancache[p1][1], work)
            cachedelta = self.rev(p1), deltatext
            text = util.buffer(arraytext)
        else:
            # The first parent manifest isn't already loaded, so we'll
            # just encode a fulltext of the manifest and pass that
            # through to the revlog layer, and let it handle the delta
            # process.
            text = map.text()
            arraytext = array.array('c', text)
            cachedelta = None

        n = self.addrevision(text, transaction, link, p1, p2, cachedelta)
        self._mancache[n] = (map, arraytext)

        return n