view mercurial/parser.py @ 21933:8ecbe55fd09d stable

largefiles: invoke "normallookup" on "lfdirstate" for merged files

Before this patch, largefiles gotten from "other" revision (with
conflict) at "hg merge" become "clean" unexpectedly in steps below:

    1. "repo.status()" is invoked (for status check before merging)
      1-1 "dirstate" entry for standinfile SF is "normal"-ed
      1-2 "lfdirstate" entry of largefile LF (for SF) is "normal"-ed

    2. "merge.update()" is invoked
      2-1 SF is updated in the working directory
          (ASSUMPTION: user choice "other" at conflict)
      2-2 "dirstate" entry for SF is "merge"-ed

    3. "lfcommands.updatelfiles()" is invoked (by "overrides.hgmerge()")
      3-1 largefile LF (for SF) is updated in the working directory
      3-2 "dirstate" returns "m" for SF (by 2-2)
      3-3 "lfdirstate" entry for LF is left as it is
      3-4 "lfdirstate" is written into ".hg/largefiles/dirstate", and
          timestamp of LF is stored into "lfdirstate" file (by 1-2)
          (ASSUMPTION: timestamp of LF differs from one of "lfdirstate" file)

Then, "hs status" treats LF as "clean", even though LF is updated by
"other" revision (by 3-1), because "lfilesrepo.status()" always treats
"normal"-ed files (by 1-2 and 3-4) as "clean".

When state of standinfile in "dirstate" is "m", largefile should be
"normallookup"-ed.

This patch invokes "normallookup" on "lfdirstate" for merged files.

This patch uses "[debug] dirstate.delaywrite" feature in the test, to
ensure that timestamp of the largefile gotten from "other" revision is
stored into ".hg/largefiles/dirstate". (for ASSUMPTION at 3-4)

# parser.py - simple top-down operator precedence parser for mercurial
#
# Copyright 2010 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.

# see http://effbot.org/zone/simple-top-down-parsing.htm and
# http://eli.thegreenplace.net/2010/01/02/top-down-operator-precedence-parsing/
# for background

# takes a tokenizer and elements
# tokenizer is an iterator that returns type, value pairs
# elements is a mapping of types to binding strength, prefix and infix actions
# an action is a tree node name, a tree label, and an optional match
# __call__(program) parses program into a labeled tree

import error
from i18n import _

class parser(object):
    def __init__(self, tokenizer, elements, methods=None):
        self._tokenizer = tokenizer
        self._elements = elements
        self._methods = methods
        self.current = None
    def _advance(self):
        'advance the tokenizer'
        t = self.current
        try:
            self.current = self._iter.next()
        except StopIteration:
            pass
        return t
    def _match(self, m, pos):
        'make sure the tokenizer matches an end condition'
        if self.current[0] != m:
            raise error.ParseError(_("unexpected token: %s") % self.current[0],
                                   self.current[2])
        self._advance()
    def _parse(self, bind=0):
        token, value, pos = self._advance()
        # handle prefix rules on current token
        prefix = self._elements[token][1]
        if not prefix:
            raise error.ParseError(_("not a prefix: %s") % token, pos)
        if len(prefix) == 1:
            expr = (prefix[0], value)
        else:
            if len(prefix) > 2 and prefix[2] == self.current[0]:
                self._match(prefix[2], pos)
                expr = (prefix[0], None)
            else:
                expr = (prefix[0], self._parse(prefix[1]))
                if len(prefix) > 2:
                    self._match(prefix[2], pos)
        # gather tokens until we meet a lower binding strength
        while bind < self._elements[self.current[0]][0]:
            token, value, pos = self._advance()
            e = self._elements[token]
            # check for suffix - next token isn't a valid prefix
            if len(e) == 4 and not self._elements[self.current[0]][1]:
                suffix = e[3]
                expr = (suffix[0], expr)
            else:
                # handle infix rules
                if len(e) < 3 or not e[2]:
                    raise error.ParseError(_("not an infix: %s") % token, pos)
                infix = e[2]
                if len(infix) == 3 and infix[2] == self.current[0]:
                    self._match(infix[2], pos)
                    expr = (infix[0], expr, (None))
                else:
                    expr = (infix[0], expr, self._parse(infix[1]))
                    if len(infix) == 3:
                        self._match(infix[2], pos)
        return expr
    def parse(self, message, lookup=None):
        'generate a parse tree from a message'
        if lookup:
            self._iter = self._tokenizer(message, lookup)
        else:
            self._iter = self._tokenizer(message)
        self._advance()
        res = self._parse()
        token, value, pos = self.current
        return res, pos
    def eval(self, tree):
        'recursively evaluate a parse tree using node methods'
        if not isinstance(tree, tuple):
            return tree
        return self._methods[tree[0]](*[self.eval(t) for t in tree[1:]])
    def __call__(self, message):
        'parse a message into a parse tree and evaluate if methods given'
        t = self.parse(message)
        if self._methods:
            return self.eval(t)
        return t