# HG changeset patch
# User Matt Mackall <mpm@selenic.com>
# Date 1202088545 21600
#      Sun Feb 03 19:29:05 2008 -0600
# Node ID abd66eb0889e3efaca4f960e0eacd719c18880dd
# Parent  30d2fecaab7634c0185fd951bf72d7ad7eb6401d
merge: move the bulk of simplemerge into core

- keep existing simplemerge command in contrib
- clean up test interface

diff --git a/contrib/simplemerge b/contrib/simplemerge
--- a/contrib/simplemerge
+++ b/contrib/simplemerge
@@ -1,503 +1,11 @@
 #!/usr/bin/env python
-# Copyright (C) 2004, 2005 Canonical Ltd
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-
-# mbp: "you know that thing where cvs gives you conflict markers?"
-# s: "i hate that."
 
 from mercurial import demandimport
 demandimport.enable()
 
-from mercurial import util, mdiff, fancyopts
+import os, sys
 from mercurial.i18n import _
-
-
-class CantReprocessAndShowBase(Exception):
-    pass
-
-
-def warn(message):
-    sys.stdout.flush()
-    sys.stderr.write(message)
-    sys.stderr.flush()
-
-
-def intersect(ra, rb):
-    """Given two ranges return the range where they intersect or None.
-
-    >>> intersect((0, 10), (0, 6))
-    (0, 6)
-    >>> intersect((0, 10), (5, 15))
-    (5, 10)
-    >>> intersect((0, 10), (10, 15))
-    >>> intersect((0, 9), (10, 15))
-    >>> intersect((0, 9), (7, 15))
-    (7, 9)
-    """
-    assert ra[0] <= ra[1]
-    assert rb[0] <= rb[1]
-
-    sa = max(ra[0], rb[0])
-    sb = min(ra[1], rb[1])
-    if sa < sb:
-        return sa, sb
-    else:
-        return None
-
-
-def compare_range(a, astart, aend, b, bstart, bend):
-    """Compare a[astart:aend] == b[bstart:bend], without slicing.
-    """
-    if (aend-astart) != (bend-bstart):
-        return False
-    for ia, ib in zip(xrange(astart, aend), xrange(bstart, bend)):
-        if a[ia] != b[ib]:
-            return False
-    else:
-        return True
-
-
-
-
-class Merge3Text(object):
-    """3-way merge of texts.
-
-    Given strings BASE, OTHER, THIS, tries to produce a combined text
-    incorporating the changes from both BASE->OTHER and BASE->THIS."""
-    def __init__(self, basetext, atext, btext, base=None, a=None, b=None):
-        self.basetext = basetext
-        self.atext = atext
-        self.btext = btext
-        if base is None:
-            base = mdiff.splitnewlines(basetext)
-        if a is None:
-            a = mdiff.splitnewlines(atext)
-        if b is None:
-            b = mdiff.splitnewlines(btext)
-        self.base = base
-        self.a = a
-        self.b = b
-
-
-
-    def merge_lines(self,
-                    name_a=None,
-                    name_b=None,
-                    name_base=None,
-                    start_marker='<<<<<<<',
-                    mid_marker='=======',
-                    end_marker='>>>>>>>',
-                    base_marker=None,
-                    reprocess=False):
-        """Return merge in cvs-like form.
-        """
-        self.conflicts = False
-        newline = '\n'
-        if len(self.a) > 0:
-            if self.a[0].endswith('\r\n'):
-                newline = '\r\n'
-            elif self.a[0].endswith('\r'):
-                newline = '\r'
-        if base_marker and reprocess:
-            raise CantReprocessAndShowBase()
-        if name_a:
-            start_marker = start_marker + ' ' + name_a
-        if name_b:
-            end_marker = end_marker + ' ' + name_b
-        if name_base and base_marker:
-            base_marker = base_marker + ' ' + name_base
-        merge_regions = self.merge_regions()
-        if reprocess is True:
-            merge_regions = self.reprocess_merge_regions(merge_regions)
-        for t in merge_regions:
-            what = t[0]
-            if what == 'unchanged':
-                for i in range(t[1], t[2]):
-                    yield self.base[i]
-            elif what == 'a' or what == 'same':
-                for i in range(t[1], t[2]):
-                    yield self.a[i]
-            elif what == 'b':
-                for i in range(t[1], t[2]):
-                    yield self.b[i]
-            elif what == 'conflict':
-                self.conflicts = True
-                yield start_marker + newline
-                for i in range(t[3], t[4]):
-                    yield self.a[i]
-                if base_marker is not None:
-                    yield base_marker + newline
-                    for i in range(t[1], t[2]):
-                        yield self.base[i]
-                yield mid_marker + newline
-                for i in range(t[5], t[6]):
-                    yield self.b[i]
-                yield end_marker + newline
-            else:
-                raise ValueError(what)
-
-
-
-
-
-    def merge_annotated(self):
-        """Return merge with conflicts, showing origin of lines.
-
-        Most useful for debugging merge.
-        """
-        for t in self.merge_regions():
-            what = t[0]
-            if what == 'unchanged':
-                for i in range(t[1], t[2]):
-                    yield 'u | ' + self.base[i]
-            elif what == 'a' or what == 'same':
-                for i in range(t[1], t[2]):
-                    yield what[0] + ' | ' + self.a[i]
-            elif what == 'b':
-                for i in range(t[1], t[2]):
-                    yield 'b | ' + self.b[i]
-            elif what == 'conflict':
-                yield '<<<<\n'
-                for i in range(t[3], t[4]):
-                    yield 'A | ' + self.a[i]
-                yield '----\n'
-                for i in range(t[5], t[6]):
-                    yield 'B | ' + self.b[i]
-                yield '>>>>\n'
-            else:
-                raise ValueError(what)
-
-
-
-
-
-    def merge_groups(self):
-        """Yield sequence of line groups.  Each one is a tuple:
-
-        'unchanged', lines
-             Lines unchanged from base
-
-        'a', lines
-             Lines taken from a
-
-        'same', lines
-             Lines taken from a (and equal to b)
-
-        'b', lines
-             Lines taken from b
-
-        'conflict', base_lines, a_lines, b_lines
-             Lines from base were changed to either a or b and conflict.
-        """
-        for t in self.merge_regions():
-            what = t[0]
-            if what == 'unchanged':
-                yield what, self.base[t[1]:t[2]]
-            elif what == 'a' or what == 'same':
-                yield what, self.a[t[1]:t[2]]
-            elif what == 'b':
-                yield what, self.b[t[1]:t[2]]
-            elif what == 'conflict':
-                yield (what,
-                       self.base[t[1]:t[2]],
-                       self.a[t[3]:t[4]],
-                       self.b[t[5]:t[6]])
-            else:
-                raise ValueError(what)
-
-
-    def merge_regions(self):
-        """Return sequences of matching and conflicting regions.
-
-        This returns tuples, where the first value says what kind we
-        have:
-
-        'unchanged', start, end
-             Take a region of base[start:end]
-
-        'same', astart, aend
-             b and a are different from base but give the same result
-
-        'a', start, end
-             Non-clashing insertion from a[start:end]
-
-        Method is as follows:
-
-        The two sequences align only on regions which match the base
-        and both descendents.  These are found by doing a two-way diff
-        of each one against the base, and then finding the
-        intersections between those regions.  These "sync regions"
-        are by definition unchanged in both and easily dealt with.
-
-        The regions in between can be in any of three cases:
-        conflicted, or changed on only one side.
-        """
-
-        # section a[0:ia] has been disposed of, etc
-        iz = ia = ib = 0
-
-        for zmatch, zend, amatch, aend, bmatch, bend in self.find_sync_regions():
-            #print 'match base [%d:%d]' % (zmatch, zend)
-
-            matchlen = zend - zmatch
-            assert matchlen >= 0
-            assert matchlen == (aend - amatch)
-            assert matchlen == (bend - bmatch)
-
-            len_a = amatch - ia
-            len_b = bmatch - ib
-            len_base = zmatch - iz
-            assert len_a >= 0
-            assert len_b >= 0
-            assert len_base >= 0
-
-            #print 'unmatched a=%d, b=%d' % (len_a, len_b)
-
-            if len_a or len_b:
-                # try to avoid actually slicing the lists
-                equal_a = compare_range(self.a, ia, amatch,
-                                        self.base, iz, zmatch)
-                equal_b = compare_range(self.b, ib, bmatch,
-                                        self.base, iz, zmatch)
-                same = compare_range(self.a, ia, amatch,
-                                     self.b, ib, bmatch)
-
-                if same:
-                    yield 'same', ia, amatch
-                elif equal_a and not equal_b:
-                    yield 'b', ib, bmatch
-                elif equal_b and not equal_a:
-                    yield 'a', ia, amatch
-                elif not equal_a and not equal_b:
-                    yield 'conflict', iz, zmatch, ia, amatch, ib, bmatch
-                else:
-                    raise AssertionError("can't handle a=b=base but unmatched")
-
-                ia = amatch
-                ib = bmatch
-            iz = zmatch
-
-            # if the same part of the base was deleted on both sides
-            # that's OK, we can just skip it.
-
-
-            if matchlen > 0:
-                assert ia == amatch
-                assert ib == bmatch
-                assert iz == zmatch
-
-                yield 'unchanged', zmatch, zend
-                iz = zend
-                ia = aend
-                ib = bend
-
-
-    def reprocess_merge_regions(self, merge_regions):
-        """Where there are conflict regions, remove the agreed lines.
-
-        Lines where both A and B have made the same changes are
-        eliminated.
-        """
-        for region in merge_regions:
-            if region[0] != "conflict":
-                yield region
-                continue
-            type, iz, zmatch, ia, amatch, ib, bmatch = region
-            a_region = self.a[ia:amatch]
-            b_region = self.b[ib:bmatch]
-            matches = mdiff.get_matching_blocks(''.join(a_region),
-                                                ''.join(b_region))
-            next_a = ia
-            next_b = ib
-            for region_ia, region_ib, region_len in matches[:-1]:
-                region_ia += ia
-                region_ib += ib
-                reg = self.mismatch_region(next_a, region_ia, next_b,
-                                           region_ib)
-                if reg is not None:
-                    yield reg
-                yield 'same', region_ia, region_len+region_ia
-                next_a = region_ia + region_len
-                next_b = region_ib + region_len
-            reg = self.mismatch_region(next_a, amatch, next_b, bmatch)
-            if reg is not None:
-                yield reg
-
-
-    def mismatch_region(next_a, region_ia,  next_b, region_ib):
-        if next_a < region_ia or next_b < region_ib:
-            return 'conflict', None, None, next_a, region_ia, next_b, region_ib
-    mismatch_region = staticmethod(mismatch_region)
-
-
-    def find_sync_regions(self):
-        """Return a list of sync regions, where both descendents match the base.
-
-        Generates a list of (base1, base2, a1, a2, b1, b2).  There is
-        always a zero-length sync region at the end of all the files.
-        """
-
-        ia = ib = 0
-        amatches = mdiff.get_matching_blocks(self.basetext, self.atext)
-        bmatches = mdiff.get_matching_blocks(self.basetext, self.btext)
-        len_a = len(amatches)
-        len_b = len(bmatches)
-
-        sl = []
-
-        while ia < len_a and ib < len_b:
-            abase, amatch, alen = amatches[ia]
-            bbase, bmatch, blen = bmatches[ib]
-
-            # there is an unconflicted block at i; how long does it
-            # extend?  until whichever one ends earlier.
-            i = intersect((abase, abase+alen), (bbase, bbase+blen))
-            if i:
-                intbase = i[0]
-                intend = i[1]
-                intlen = intend - intbase
-
-                # found a match of base[i[0], i[1]]; this may be less than
-                # the region that matches in either one
-                assert intlen <= alen
-                assert intlen <= blen
-                assert abase <= intbase
-                assert bbase <= intbase
-
-                asub = amatch + (intbase - abase)
-                bsub = bmatch + (intbase - bbase)
-                aend = asub + intlen
-                bend = bsub + intlen
-
-                assert self.base[intbase:intend] == self.a[asub:aend], \
-                       (self.base[intbase:intend], self.a[asub:aend])
-
-                assert self.base[intbase:intend] == self.b[bsub:bend]
-
-                sl.append((intbase, intend,
-                           asub, aend,
-                           bsub, bend))
-
-            # advance whichever one ends first in the base text
-            if (abase + alen) < (bbase + blen):
-                ia += 1
-            else:
-                ib += 1
-
-        intbase = len(self.base)
-        abase = len(self.a)
-        bbase = len(self.b)
-        sl.append((intbase, intbase, abase, abase, bbase, bbase))
-
-        return sl
-
-
-
-    def find_unconflicted(self):
-        """Return a list of ranges in base that are not conflicted."""
-        am = mdiff.get_matching_blocks(self.basetext, self.atext)
-        bm = mdiff.get_matching_blocks(self.basetext, self.btext)
-
-        unc = []
-
-        while am and bm:
-            # there is an unconflicted block at i; how long does it
-            # extend?  until whichever one ends earlier.
-            a1 = am[0][0]
-            a2 = a1 + am[0][2]
-            b1 = bm[0][0]
-            b2 = b1 + bm[0][2]
-            i = intersect((a1, a2), (b1, b2))
-            if i:
-                unc.append(i)
-
-            if a2 < b2:
-                del am[0]
-            else:
-                del bm[0]
-
-        return unc
-
-
-# bzr compatible interface, for the tests
-class Merge3(Merge3Text):
-    """3-way merge of texts.
-
-    Given BASE, OTHER, THIS, tries to produce a combined text
-    incorporating the changes from both BASE->OTHER and BASE->THIS.
-    All three will typically be sequences of lines."""
-    def __init__(self, base, a, b):
-        basetext = '\n'.join([i.strip('\n') for i in base] + [''])
-        atext = '\n'.join([i.strip('\n') for i in a] + [''])
-        btext = '\n'.join([i.strip('\n') for i in b] + [''])
-        if util.binary(basetext) or util.binary(atext) or util.binary(btext):
-            raise util.Abort(_("don't know how to merge binary files"))
-        Merge3Text.__init__(self, basetext, atext, btext, base, a, b)
-
-
-def simplemerge(local, base, other, **opts):
-    def readfile(filename):
-        f = open(filename, "rb")
-        text = f.read()
-        f.close()
-        if util.binary(text):
-            msg = _("%s looks like a binary file.") % filename
-            if not opts.get('text'):
-                raise util.Abort(msg)
-            elif not opts.get('quiet'):
-                warn(_('warning: %s\n') % msg)
-        return text
-
-    name_a = local
-    name_b = other
-    labels = opts.get('label', [])
-    if labels:
-        name_a = labels.pop(0)
-    if labels:
-        name_b = labels.pop(0)
-    if labels:
-        raise util.Abort(_("can only specify two labels."))
-
-    localtext = readfile(local)
-    basetext = readfile(base)
-    othertext = readfile(other)
-
-    orig = local
-    local = os.path.realpath(local)
-    if not opts.get('print'):
-        opener = util.opener(os.path.dirname(local))
-        out = opener(os.path.basename(local), "w", atomictemp=True)
-    else:
-        out = sys.stdout
-
-    reprocess = not opts.get('no_minimal')
-
-    m3 = Merge3Text(basetext, localtext, othertext)
-    for line in m3.merge_lines(name_a=name_a, name_b=name_b,
-                               reprocess=reprocess):
-        out.write(line)
-
-    if not opts.get('print'):
-        out.rename()
-
-    if m3.conflicts:
-        if not opts.get('quiet'):
-            warn(_("warning: conflicts during merge.\n"))
-        return 1
+from mercurial import simplemerge, fancyopts, util
 
 options = [('L', 'label', [], _('labels to use on conflict markers')),
            ('a', 'text', None, _('treat all files as text')),
@@ -517,6 +25,9 @@
     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():
     sys.stdout.write(usage)
     sys.stdout.write('\noptions:\n')
@@ -530,33 +41,24 @@
     for first, second in out_opts:
         sys.stdout.write(' %-*s  %s\n' % (opts_len, first, second))
 
-class ParseError(Exception):
-    """Exception raised on errors in parsing the command line."""
-
-def main(argv):
+try:
+    opts = {}
     try:
-        opts = {}
-        try:
-            args = fancyopts.fancyopts(argv[1:], options, opts)
-        except fancyopts.getopt.GetoptError, e:
-            raise ParseError(e)
-        if opts['help']:
-            showhelp()
-            return 0
-        if len(args) != 3:
-                raise ParseError(_('wrong number of arguments'))
-        return simplemerge(*args, **opts)
-    except ParseError, e:
-        sys.stdout.write("%s: %s\n" % (sys.argv[0], e))
+        args = fancyopts.fancyopts(sys.argv[1:], options, opts)
+    except fancyopts.getopt.GetoptError, e:
+        raise ParseError(e)
+    if opts['help']:
         showhelp()
-        return 1
-    except util.Abort, e:
-        sys.stderr.write("abort: %s\n" % e)
-        return 255
-    except KeyboardInterrupt:
-        return 255
-
-if __name__ == '__main__':
-    import sys
-    import os
-    sys.exit(main(sys.argv))
+        sys.exit(0)
+    if len(args) != 3:
+            raise ParseError(_('wrong number of arguments'))
+    sys.exit(simplemerge.simplemerge(*args, **opts))
+except ParseError, e:
+    sys.stdout.write("%s: %s\n" % (sys.argv[0], e))
+    showhelp()
+    sys.exit(1)
+except util.Abort, e:
+    sys.stderr.write("abort: %s\n" % e)
+    sys.exit(255)
+except KeyboardInterrupt:
+    sys.exit(255)
diff --git a/contrib/simplemerge b/mercurial/simplemerge.py
copy from contrib/simplemerge
copy to mercurial/simplemerge.py
--- a/contrib/simplemerge
+++ b/mercurial/simplemerge.py
@@ -15,27 +15,20 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
-
 # mbp: "you know that thing where cvs gives you conflict markers?"
 # s: "i hate that."
 
-from mercurial import demandimport
-demandimport.enable()
-
-from mercurial import util, mdiff, fancyopts
-from mercurial.i18n import _
-
+from i18n import _
+import util, mdiff, fancyopts, sys, os
 
 class CantReprocessAndShowBase(Exception):
     pass
 
-
 def warn(message):
     sys.stdout.flush()
     sys.stderr.write(message)
     sys.stderr.flush()
 
-
 def intersect(ra, rb):
     """Given two ranges return the range where they intersect or None.
 
@@ -58,7 +51,6 @@
     else:
         return None
 
-
 def compare_range(a, astart, aend, b, bstart, bend):
     """Compare a[astart:aend] == b[bstart:bend], without slicing.
     """
@@ -70,9 +62,6 @@
     else:
         return True
 
-
-
-
 class Merge3Text(object):
     """3-way merge of texts.
 
@@ -92,8 +81,6 @@
         self.a = a
         self.b = b
 
-
-
     def merge_lines(self,
                     name_a=None,
                     name_b=None,
@@ -150,10 +137,6 @@
             else:
                 raise ValueError(what)
 
-
-
-
-
     def merge_annotated(self):
         """Return merge with conflicts, showing origin of lines.
 
@@ -181,10 +164,6 @@
             else:
                 raise ValueError(what)
 
-
-
-
-
     def merge_groups(self):
         """Yield sequence of line groups.  Each one is a tuple:
 
@@ -219,7 +198,6 @@
             else:
                 raise ValueError(what)
 
-
     def merge_regions(self):
         """Return sequences of matching and conflicting regions.
 
@@ -305,7 +283,6 @@
                 ia = aend
                 ib = bend
 
-
     def reprocess_merge_regions(self, merge_regions):
         """Where there are conflict regions, remove the agreed lines.
 
@@ -337,13 +314,11 @@
             if reg is not None:
                 yield reg
 
-
     def mismatch_region(next_a, region_ia,  next_b, region_ib):
         if next_a < region_ia or next_b < region_ib:
             return 'conflict', None, None, next_a, region_ia, next_b, region_ib
     mismatch_region = staticmethod(mismatch_region)
 
-
     def find_sync_regions(self):
         """Return a list of sync regions, where both descendents match the base.
 
@@ -405,8 +380,6 @@
 
         return sl
 
-
-
     def find_unconflicted(self):
         """Return a list of ranges in base that are not conflicted."""
         am = mdiff.get_matching_blocks(self.basetext, self.atext)
@@ -432,23 +405,6 @@
 
         return unc
 
-
-# bzr compatible interface, for the tests
-class Merge3(Merge3Text):
-    """3-way merge of texts.
-
-    Given BASE, OTHER, THIS, tries to produce a combined text
-    incorporating the changes from both BASE->OTHER and BASE->THIS.
-    All three will typically be sequences of lines."""
-    def __init__(self, base, a, b):
-        basetext = '\n'.join([i.strip('\n') for i in base] + [''])
-        atext = '\n'.join([i.strip('\n') for i in a] + [''])
-        btext = '\n'.join([i.strip('\n') for i in b] + [''])
-        if util.binary(basetext) or util.binary(atext) or util.binary(btext):
-            raise util.Abort(_("don't know how to merge binary files"))
-        Merge3Text.__init__(self, basetext, atext, btext, base, a, b)
-
-
 def simplemerge(local, base, other, **opts):
     def readfile(filename):
         f = open(filename, "rb")
@@ -498,65 +454,3 @@
         if not opts.get('quiet'):
             warn(_("warning: conflicts during merge.\n"))
         return 1
-
-options = [('L', 'label', [], _('labels to use on conflict markers')),
-           ('a', 'text', None, _('treat all files as text')),
-           ('p', 'print', None,
-            _('print results instead of overwriting LOCAL')),
-           ('', 'no-minimal', None,
-            _('do not try to minimize conflict regions')),
-           ('h', 'help', None, _('display help and exit')),
-           ('q', 'quiet', None, _('suppress output'))]
-
-usage = _('''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.
-''')
-
-def showhelp():
-    sys.stdout.write(usage)
-    sys.stdout.write('\noptions:\n')
-
-    out_opts = []
-    for shortopt, longopt, default, desc in options:
-        out_opts.append(('%2s%s' % (shortopt and '-%s' % shortopt,
-                                    longopt and ' --%s' % longopt),
-                         '%s' % desc))
-    opts_len = max([len(opt[0]) for opt in out_opts])
-    for first, second in out_opts:
-        sys.stdout.write(' %-*s  %s\n' % (opts_len, first, second))
-
-class ParseError(Exception):
-    """Exception raised on errors in parsing the command line."""
-
-def main(argv):
-    try:
-        opts = {}
-        try:
-            args = fancyopts.fancyopts(argv[1:], options, opts)
-        except fancyopts.getopt.GetoptError, e:
-            raise ParseError(e)
-        if opts['help']:
-            showhelp()
-            return 0
-        if len(args) != 3:
-                raise ParseError(_('wrong number of arguments'))
-        return simplemerge(*args, **opts)
-    except ParseError, e:
-        sys.stdout.write("%s: %s\n" % (sys.argv[0], e))
-        showhelp()
-        return 1
-    except util.Abort, e:
-        sys.stderr.write("abort: %s\n" % e)
-        return 255
-    except KeyboardInterrupt:
-        return 255
-
-if __name__ == '__main__':
-    import sys
-    import os
-    sys.exit(main(sys.argv))
diff --git a/tests/test-simplemerge.py b/tests/test-simplemerge.py
--- a/tests/test-simplemerge.py
+++ b/tests/test-simplemerge.py
@@ -19,14 +19,24 @@
 from unittest import TestCase
 import imp
 import shutil
-from mercurial import util
+from mercurial import util, simplemerge
+
+# bzr compatible interface, for the tests
+class Merge3(simplemerge.Merge3Text):
+    """3-way merge of texts.
 
-# copy simplemerge to the cwd to avoid creating a .pyc file in the source tree
-shutil.copyfile(os.path.join(os.environ['TESTDIR'], os.path.pardir,
-                             'contrib', 'simplemerge'),
-                'simplemerge.py')
-simplemerge = imp.load_source('simplemerge', 'simplemerge.py')
-Merge3 = simplemerge.Merge3
+    Given BASE, OTHER, THIS, tries to produce a combined text
+    incorporating the changes from both BASE->OTHER and BASE->THIS.
+    All three will typically be sequences of lines."""
+    def __init__(self, base, a, b):
+        basetext = '\n'.join([i.strip('\n') for i in base] + [''])
+        atext = '\n'.join([i.strip('\n') for i in a] + [''])
+        btext = '\n'.join([i.strip('\n') for i in b] + [''])
+        if util.binary(basetext) or util.binary(atext) or util.binary(btext):
+            raise util.Abort("don't know how to merge binary files")
+        simplemerge.Merge3Text.__init__(self, basetext, atext, btext,
+                                        base, a, b)
+
 CantReprocessAndShowBase = simplemerge.CantReprocessAndShowBase
 
 def split_lines(t):