mercurial/filemerge.py

dagparser: parses and formats DAGs as concise text

As discussed during the sprint. See the doc comment and doctests
for specification and examples. This is used in subsequent patches
to export revlog and changelog DAGs, and to generate a repo with
a given changelog DAG.

# filemerge.py - file-level merge handling for Mercurial
#
# Copyright 2006, 2007, 2008 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 node import short
from i18n import _
import util, simplemerge, match, error
import os, tempfile, re, filecmp

def _toolstr(ui, tool, part, default=""):
    return ui.config("merge-tools", tool + "." + part, default)

def _toolbool(ui, tool, part, default=False):
    return ui.configbool("merge-tools", tool + "." + part, default)

def _toollist(ui, tool, part, default=[]):
    return ui.configlist("merge-tools", tool + "." + part, default)

_internal = ['internal:' + s
             for s in 'fail local other merge prompt dump'.split()]

def _findtool(ui, tool):
    if tool in _internal:
        return tool
    k = _toolstr(ui, tool, "regkey")
    if k:
        p = util.lookup_reg(k, _toolstr(ui, tool, "regname"))
        if p:
            p = util.find_exe(p + _toolstr(ui, tool, "regappend"))
            if p:
                return p
    return util.find_exe(_toolstr(ui, tool, "executable", tool))

def _picktool(repo, ui, path, binary, symlink):
    def check(tool, pat, symlink, binary):
        tmsg = tool
        if pat:
            tmsg += " specified for " + pat
        if not _findtool(ui, tool):
            if pat: # explicitly requested tool deserves a warning
                ui.warn(_("couldn't find merge tool %s\n") % tmsg)
            else: # configured but non-existing tools are more silent
                ui.note(_("couldn't find merge tool %s\n") % tmsg)
        elif symlink and not _toolbool(ui, tool, "symlink"):
            ui.warn(_("tool %s can't handle symlinks\n") % tmsg)
        elif binary and not _toolbool(ui, tool, "binary"):
            ui.warn(_("tool %s can't handle binary\n") % tmsg)
        elif not util.gui() and _toolbool(ui, tool, "gui"):
            ui.warn(_("tool %s requires a GUI\n") % tmsg)
        else:
            return True
        return False

    # HGMERGE takes precedence
    hgmerge = os.environ.get("HGMERGE")
    if hgmerge:
        return (hgmerge, hgmerge)

    # then patterns
    for pat, tool in ui.configitems("merge-patterns"):
        mf = match.match(repo.root, '', [pat])
        if mf(path) and check(tool, pat, symlink, False):
            toolpath = _findtool(ui, tool)
            return (tool, '"' + toolpath + '"')

    # then merge tools
    tools = {}
    for k, v in ui.configitems("merge-tools"):
        t = k.split('.')[0]
        if t not in tools:
            tools[t] = int(_toolstr(ui, t, "priority", "0"))
    names = tools.keys()
    tools = sorted([(-p, t) for t, p in tools.items()])
    uimerge = ui.config("ui", "merge")
    if uimerge:
        if uimerge not in names:
            return (uimerge, uimerge)
        tools.insert(0, (None, uimerge)) # highest priority
    tools.append((None, "hgmerge")) # the old default, if found
    for p, t in tools:
        if check(t, None, symlink, binary):
            toolpath = _findtool(ui, t)
            return (t, '"' + toolpath + '"')
    # internal merge as last resort
    return (not (symlink or binary) and "internal:merge" or None, None)

def _eoltype(data):
    "Guess the EOL type of a file"
    if '\0' in data: # binary
        return None
    if '\r\n' in data: # Windows
        return '\r\n'
    if '\r' in data: # Old Mac
        return '\r'
    if '\n' in data: # UNIX
        return '\n'
    return None # unknown

def _matcheol(file, origfile):
    "Convert EOL markers in a file to match origfile"
    tostyle = _eoltype(open(origfile, "rb").read())
    if tostyle:
        data = open(file, "rb").read()
        style = _eoltype(data)
        if style:
            newdata = data.replace(style, tostyle)
            if newdata != data:
                open(file, "wb").write(newdata)

def filemerge(repo, mynode, orig, fcd, fco, fca):
    """perform a 3-way merge in the working directory

    mynode = parent node before merge
    orig = original local filename before merge
    fco = other file context
    fca = ancestor file context
    fcd = local file context for current/destination file
    """

    def temp(prefix, ctx):
        pre = "%s~%s." % (os.path.basename(ctx.path()), prefix)
        (fd, name) = tempfile.mkstemp(prefix=pre)
        data = repo.wwritedata(ctx.path(), ctx.data())
        f = os.fdopen(fd, "wb")
        f.write(data)
        f.close()
        return name

    def isbin(ctx):
        try:
            return util.binary(ctx.data())
        except IOError:
            return False

    if not fco.cmp(fcd.data()): # files identical?
        return None

    if fca == fco: # backwards, use working dir parent as ancestor
        fca = fcd.parents()[0]

    ui = repo.ui
    fd = fcd.path()
    binary = isbin(fcd) or isbin(fco) or isbin(fca)
    symlink = 'l' in fcd.flags() + fco.flags()
    tool, toolpath = _picktool(repo, ui, fd, binary, symlink)
    ui.debug("picked tool '%s' for %s (binary %s symlink %s)\n" %
               (tool, fd, binary, symlink))

    if not tool or tool == 'internal:prompt':
        tool = "internal:local"
        if ui.promptchoice(_(" no tool found to merge %s\n"
                             "keep (l)ocal or take (o)ther?") % fd,
                           (_("&Local"), _("&Other")), 0):
            tool = "internal:other"
    if tool == "internal:local":
        return 0
    if tool == "internal:other":
        repo.wwrite(fd, fco.data(), fco.flags())
        return 0
    if tool == "internal:fail":
        return 1

    # do the actual merge
    a = repo.wjoin(fd)
    b = temp("base", fca)
    c = temp("other", fco)
    out = ""
    back = a + ".orig"
    util.copyfile(a, back)

    if orig != fco.path():
        ui.status(_("merging %s and %s to %s\n") % (orig, fco.path(), fd))
    else:
        ui.status(_("merging %s\n") % fd)

    ui.debug("my %s other %s ancestor %s\n" % (fcd, fco, fca))

    # do we attempt to simplemerge first?
    try:
        premerge = _toolbool(ui, tool, "premerge", not (binary or symlink))
    except error.ConfigError:
        premerge = _toolstr(ui, tool, "premerge").lower()
        valid = 'keep'.split()
        if premerge not in valid:
            _valid = ', '.join(["'" + v + "'" for v in valid])
            raise error.ConfigError(_("%s.premerge not valid "
                                      "('%s' is neither boolean nor %s)") %
                                    (tool, premerge, _valid))

    if premerge:
        r = simplemerge.simplemerge(ui, a, b, c, quiet=True)
        if not r:
            ui.debug(" premerge successful\n")
            os.unlink(back)
            os.unlink(b)
            os.unlink(c)
            return 0
        if premerge != 'keep':
            util.copyfile(back, a) # restore from backup and try again

    env = dict(HG_FILE=fd,
               HG_MY_NODE=short(mynode),
               HG_OTHER_NODE=str(fco.changectx()),
               HG_BASE_NODE=str(fca.changectx()),
               HG_MY_ISLINK='l' in fcd.flags(),
               HG_OTHER_ISLINK='l' in fco.flags(),
               HG_BASE_ISLINK='l' in fca.flags())

    if tool == "internal:merge":
        r = simplemerge.simplemerge(ui, a, b, c, label=['local', 'other'])
    elif tool == 'internal:dump':
        a = repo.wjoin(fd)
        util.copyfile(a, a + ".local")
        repo.wwrite(fd + ".other", fco.data(), fco.flags())
        repo.wwrite(fd + ".base", fca.data(), fca.flags())
        return 1 # unresolved
    else:
        args = _toolstr(ui, tool, "args", '$local $base $other')
        if "$output" in args:
            out, a = a, back # read input from backup, write to original
        replace = dict(local=a, base=b, other=c, output=out)
        args = re.sub("\$(local|base|other|output)",
            lambda x: '"%s"' % util.localpath(replace[x.group()[1:]]), args)
        r = util.system(toolpath + ' ' + args, cwd=repo.root, environ=env)

    if not r and (_toolbool(ui, tool, "checkconflicts") or
                  'conflicts' in _toollist(ui, tool, "check")):
        if re.match("^(<<<<<<< .*|=======|>>>>>>> .*)$", fcd.data()):
            r = 1

    checked = False
    if 'prompt' in _toollist(ui, tool, "check"):
        checked = True
        if ui.promptchoice(_("was merge of '%s' successful (yn)?") % fd,
                           (_("&Yes"), _("&No")), 1):
            r = 1

    if not r and not checked and (_toolbool(ui, tool, "checkchanged") or
                                  'changed' in _toollist(ui, tool, "check")):
        if filecmp.cmp(repo.wjoin(fd), back):
            if ui.promptchoice(_(" output file %s appears unchanged\n"
                                 "was merge successful (yn)?") % fd,
                               (_("&Yes"), _("&No")), 1):
                r = 1

    if _toolbool(ui, tool, "fixeol"):
        _matcheol(repo.wjoin(fd), back)

    if r:
        ui.warn(_("merging %s failed!\n") % fd)
    else:
        os.unlink(back)

    os.unlink(b)
    os.unlink(c)
    return r