contrib/simplemerge

filemerge: make `_maketempfiles()` more reusable

`_maketempfiles()` is very specialized for its current use. I hope to
use it also when creating temporary files for input for tools that do
partial conflict resolution. That'll be possible if the function is
more generic. Instead of passing in two contexts (for "other" and
"base") and an optional path (for "local"), let's pass a single list
of files to make backups for. Even if we don't end up using for
partial conflict resolution, this is still a simplification (but I do
have a WIP patch for partial conflict resolution and it is able to
benefit from this).

Differential Revision: https://phab.mercurial-scm.org/D12193

#!/usr/bin/env python3
from __future__ import absolute_import

import getopt
import sys

import hgdemandimport

hgdemandimport.enable()

from mercurial.i18n import _
from mercurial import (
    context,
    error,
    fancyopts,
    simplemerge,
    ui as uimod,
    util,
)
from mercurial.utils import procutil, stringutil

options = [
    (b'L', b'label', [], _(b'labels to use on conflict markers')),
    (b'a', b'text', None, _(b'treat all files as text')),
    (b'p', b'print', None, _(b'print results instead of overwriting LOCAL')),
    (b'', b'no-minimal', None, _(b'no effect (DEPRECATED)')),
    (b'h', b'help', None, _(b'display help and exit')),
    (b'q', b'quiet', None, _(b'suppress output')),
]

usage = _(
    b'''simplemerge [OPTS] LOCAL BASE OTHER

    Simple three-way file merge utility with a minimal feature set.

    Apply to LOCAL the changes necessary to go from BASE to OTHER.

    By default, LOCAL is overwritten with the results of this operation.
'''
)


class ParseError(Exception):
    """Exception raised on errors in parsing the command line."""


def showhelp():
    procutil.stdout.write(usage)
    procutil.stdout.write(b'\noptions:\n')

    out_opts = []
    for shortopt, longopt, default, desc in options:
        out_opts.append(
            (
                b'%2s%s'
                % (
                    shortopt and b'-%s' % shortopt,
                    longopt and b' --%s' % longopt,
                ),
                b'%s' % desc,
            )
        )
    opts_len = max([len(opt[0]) for opt in out_opts])
    for first, second in out_opts:
        procutil.stdout.write(b' %-*s  %s\n' % (opts_len, first, second))


def _verifytext(input, ui, quiet=False, allow_binary=False):
    """verifies that text is non-binary (unless opts[text] is passed,
    then we just warn)"""
    if stringutil.binary(input.text()):
        msg = _(b"%s looks like a binary file.") % input.fctx.path()
        if not quiet:
            ui.warn(_(b'warning: %s\n') % msg)
        if not allow_binary:
            sys.exit(1)


try:
    for fp in (sys.stdin, procutil.stdout, sys.stderr):
        procutil.setbinary(fp)

    opts = {}
    try:
        bargv = [a.encode('utf8') for a in sys.argv[1:]]
        args = fancyopts.fancyopts(bargv, options, opts)
    except getopt.GetoptError as e:
        raise ParseError(e)
    if opts[b'help']:
        showhelp()
        sys.exit(0)
    if len(args) != 3:
        raise ParseError(_(b'wrong number of arguments').decode('utf8'))
    mode = b'merge'
    if len(opts[b'label']) > 2:
        mode = b'merge3'
    local, base, other = args
    overrides = opts[b'label']
    if len(overrides) > 3:
        raise error.InputError(b'can only specify three labels.')
    labels = [local, other, base]
    labels[: len(overrides)] = overrides
    local_input = simplemerge.MergeInput(
        context.arbitraryfilectx(local), labels[0]
    )
    other_input = simplemerge.MergeInput(
        context.arbitraryfilectx(other), labels[1]
    )
    base_input = simplemerge.MergeInput(
        context.arbitraryfilectx(base), labels[2]
    )

    quiet = opts.get(b'quiet')
    allow_binary = opts.get(b'text')
    ui = uimod.ui.load()
    _verifytext(local_input, ui, quiet=quiet, allow_binary=allow_binary)
    _verifytext(base_input, ui, quiet=quiet, allow_binary=allow_binary)
    _verifytext(other_input, ui, quiet=quiet, allow_binary=allow_binary)

    merged_text, conflicts = simplemerge.simplemerge(
        local_input,
        base_input,
        other_input,
        mode,
        allow_binary=allow_binary,
    )
    if opts.get(b'print'):
        ui.fout.write(merged_text)
    else:
        util.writefile(local, merged_text)
    sys.exit(1 if conflicts else 0)
except ParseError as e:
    e = stringutil.forcebytestr(e)
    procutil.stdout.write(b"%s: %s\n" % (sys.argv[0].encode('utf8'), e))
    showhelp()
    sys.exit(1)
except error.Abort as e:
    procutil.stderr.write(b"abort: %s\n" % e)
    sys.exit(255)
except KeyboardInterrupt:
    sys.exit(255)