comparison mercurial/merge.py @ 27027:a01ecbcfaf84

mergestate: handle additional record types specially

This works around a bug in older Mercurial versions' handling of the v2 merge
state.

We also add a bunch of tests that make sure that
(1) we correctly abort when the merge state has an unsupported record type
(2) aborting the merge, rebase or histedit continues to work and clears out the
    merge state.

27026:c93b44b79359

    F: a file to be merged entry
    D: a file that the external merge driver will merge internally
       (experimental)
    m: the external merge driver defined for this merge plus its run state
       (experimental)

    Merge driver run states (experimental):
    u: driver-resolved files unmarked -- needs to be run next time we're about
       to resolve or commit
    m: driver-resolved files marked -- only needs to be run before commit

          [type][length][content]

        `type` is a single character, `length` is a 4 byte integer, and
        `content` is an arbitrary byte sequence of length `length`.

        Returns list of records [(TYPE, data), ...]."""
        records = []
        try:
            f = self._repo.vfs(self.statepathv2)
            data = f.read()

                off += 1
                length = _unpack('>I', data[off:(off + 4)])[0]
                off += 4
                record = data[off:(off + length)]
                off += length
                records.append((rtype, record))
            f.close()
        except IOError as err:
            if err.errno != errno.ENOENT:
                raise

            if rtype == 'F':
                f.write('%s\n' % _droponode(data))
        f.close()

    def _writerecordsv2(self, records):
        """Write current state on disk in a version 2 file"""
        f = self._repo.vfs(self.statepathv2, 'w')
        for key, data in records:
            assert len(key) == 1
            format = '>sI%is' % len(data)
            f.write(_pack(format, key, len(data), data))
        f.close()

    def add(self, fcl, fco, fca, fd):

27027:a01ecbcfaf84

    F: a file to be merged entry
    D: a file that the external merge driver will merge internally
       (experimental)
    m: the external merge driver defined for this merge plus its run state
       (experimental)
    X: unsupported mandatory record type (used in tests)
    x: unsupported advisory record type (used in tests)

    Merge driver run states (experimental):
    u: driver-resolved files unmarked -- needs to be run next time we're about
       to resolve or commit
    m: driver-resolved files marked -- only needs to be run before commit

          [type][length][content]

        `type` is a single character, `length` is a 4 byte integer, and
        `content` is an arbitrary byte sequence of length `length`.

        Mercurial versions prior to 3.7 have a bug where if there are
        unsupported mandatory merge records, attempting to clear out the merge
        state with hg update --clean or similar aborts. The 't' record type
        works around that by writing out what those versions treat as an
        advisory record, but later versions interpret as special: the first
        character is the 'real' record type and everything onwards is the data.

        Returns list of records [(TYPE, data), ...]."""
        records = []
        try:
            f = self._repo.vfs(self.statepathv2)
            data = f.read()

                off += 1
                length = _unpack('>I', data[off:(off + 4)])[0]
                off += 4
                record = data[off:(off + length)]
                off += length
                if rtype == 't':
                    rtype, record = record[0], record[1:]
                records.append((rtype, record))
            f.close()
        except IOError as err:
            if err.errno != errno.ENOENT:
                raise

            if rtype == 'F':
                f.write('%s\n' % _droponode(data))
        f.close()

    def _writerecordsv2(self, records):
        """Write current state on disk in a version 2 file

        See the docstring for _readrecordsv2 for why we use 't'."""
        # these are the records that all version 2 clients can read
        whitelist = 'LOF'
        f = self._repo.vfs(self.statepathv2, 'w')
        for key, data in records:
            assert len(key) == 1
            if key not in whitelist:
                key, data = 't', '%s%s' % (key, data)
            format = '>sI%is' % len(data)
            f.write(_pack(format, key, len(data), data))
        f.close()

    def add(self, fcl, fco, fca, fd):