merge: minimize conflicts when common base is not shown (issue4447)

Previously, two changes that were nearly, but not quite, identical would result
in large merge conflict regions that looked very similar, and were thus very
confusing to users, and lead people used to other source control systems to
claim that "mercurial's merge algorithms suck". In the relatively common case
of a new file being introduced in two branches with very slight modifications,
the old behavior would show the entire file as a conflict, and it would be very
difficult for a user to determine what was going on.

In the past, mercurial attempted to solve this with a "very smart" algorithm
that would find all common lines, but this has significant problems as
described in 2ea6d906cf9b.

Instead, we use a "very dumb" algorithm introduced in the previous patch that
simply matches lines at the periphery of conflict regions. This minimizes most
conflict regions well, though there may still be some degenerate edge cases,
like small modification to the beginning and end of a large file.

mercurial/simplemerge.py

@@ -1,459 +1,466 b''
 # 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, see <http://www.gnu.org/licenses/>.
 
 # mbp: "you know that thing where cvs gives you conflict markers?"
 # s: "i hate that."
 
 from __future__ import absolute_import
 
 import os
 import sys
 
 from .i18n import _
 from . import (
     error,
     mdiff,
     scmutil,
     util,
 )
 
 class CantReprocessAndShowBase(Exception):
     pass
 
 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,
-                    localorother=None):
+                    localorother=None,
+                    minimize=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 name_a and start_marker:
             start_marker = start_marker + ' ' + name_a
         if name_b and end_marker:
             end_marker = end_marker + ' ' + name_b
         if name_base and base_marker:
             base_marker = base_marker + ' ' + name_base
         merge_regions = self.merge_regions()
+        if minimize:
+            merge_regions = self.minimize(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':
                 if localorother == 'local':
                     for i in range(t[3], t[4]):
                         yield self.a[i]
                 elif localorother == 'other':
                     for i in range(t[5], t[6]):
                         yield self.b[i]
                 else:
                     self.conflicts = True
                     if start_marker is not None:
                         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]
                     if mid_marker is not None:
                         yield mid_marker + newline
                     for i in range(t[5], t[6]):
                         yield self.b[i]
                     if end_marker is not None:
                         yield end_marker + newline
             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]
 
         'conflict', zstart, zend, astart, aend, bstart, bend
             Conflict between a and b, with z as common ancestor
 
         Method is as follows:
 
         The two sequences align only on regions which match the base
         and both descendants.  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 region in self.find_sync_regions():
             zmatch, zend, amatch, aend, bmatch, bend = region
             #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 minimize(self, merge_regions):
         """Trim conflict regions of lines where A and B sides match.
 
         Lines where both A and B have made the same changes at the begining
         or the end of each merge region are eliminated from the conflict
         region and are instead considered the same.
         """
         for region in merge_regions:
             if region[0] != "conflict":
                 yield region
                 continue
             issue, z1, z2, a1, a2, b1, b2 = region
             alen = a2 - a1
             blen = b2 - b1
 
             # find matches at the front
             ii = 0
             while ii < alen and ii < blen and \
                   self.a[a1 + ii] == self.b[b1 + ii]:
                 ii += 1
             startmatches = ii
 
             # find matches at the end
             ii = 0
             while ii < alen and ii < blen and \
                   self.a[a2 - ii - 1] == self.b[b2 - ii - 1]:
                 ii += 1
             endmatches = ii
 
             if startmatches > 0:
                 yield 'same', a1, a1 + startmatches
 
             yield ('conflict', z1, z2,
                     a1 + startmatches, a2 - endmatches,
                     b1 + startmatches, b2 - endmatches)
 
             if endmatches > 0:
                 yield 'same', a2 - endmatches, a2
 
     def find_sync_regions(self):
         """Return a list of sync regions, where both descendants 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
 
 def simplemerge(ui, 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('quiet'):
                 ui.warn(_('warning: %s\n') % msg)
             if not opts.get('text'):
                 raise error.Abort(msg)
         return text
 
     mode = opts.get('mode','merge')
     if mode == 'union':
         name_a = None
         name_b = None
         name_base = None
     else:
         name_a = local
         name_b = other
         name_base = None
         labels = opts.get('label', [])
         if len(labels) > 0:
             name_a = labels[0]
         if len(labels) > 1:
             name_b = labels[1]
         if len(labels) > 2:
             name_base = labels[2]
         if len(labels) > 3:
             raise error.Abort(_("can only specify three labels."))
 
     try:
         localtext = readfile(local)
         basetext = readfile(base)
         othertext = readfile(other)
     except error.Abort:
         return 1
 
     local = os.path.realpath(local)
     if not opts.get('print'):
         opener = scmutil.opener(os.path.dirname(local))
         out = opener(os.path.basename(local), "w", atomictemp=True)
     else:
         out = sys.stdout
 
     m3 = Merge3Text(basetext, localtext, othertext)
-    extrakwargs = {"localorother": opts.get("localorother", None)}
+    extrakwargs = {
+            "localorother": opts.get("localorother", None),
+            'minimize': True,
+        }
     if mode == 'union':
         extrakwargs['start_marker'] = None
         extrakwargs['mid_marker'] = None
         extrakwargs['end_marker'] = None
     elif name_base is not None:
         extrakwargs['base_marker'] = '|||||||'
         extrakwargs['name_base'] = name_base
+        extrakwargs['minimize'] = False
     for line in m3.merge_lines(name_a=name_a, name_b=name_b, **extrakwargs):
         out.write(line)
 
     if not opts.get('print'):
         out.close()
 
     if m3.conflicts and not mode == 'union':
         return 1

tests/test-conflict.t

@@ -1,291 +1,276 b''
   $ hg init
   $ cat << EOF > a
   > Small Mathematical Series.
   > One
   > Two
   > Three
   > Four
   > Five
   > Hop we are done.
   > EOF
   $ hg add a
   $ hg commit -m ancestor
   $ cat << EOF > a
   > Small Mathematical Series.
   > 1
   > 2
   > 3
   > 4
   > 5
   > Hop we are done.
   > EOF
   $ hg commit -m branch1
   $ hg co 0
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cat << EOF > a
   > Small Mathematical Series.
   > 1
   > 2
   > 3
   > 6
   > 8
   > Hop we are done.
   > EOF
   $ hg commit -m branch2
   created new head
 
   $ hg merge 1
   merging a
   warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
   0 files updated, 0 files merged, 0 files removed, 1 files unresolved
   use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
   [1]
 
   $ hg id
   618808747361+c0c68e4fe667+ tip
 
   $ cat a
   Small Mathematical Series.
-  <<<<<<< local: 618808747361 - test: branch2
   1
   2
   3
+  <<<<<<< local: 618808747361 - test: branch2
   6
   8
   =======
-  1
-  2
-  3
   4
   5
   >>>>>>> other: c0c68e4fe667  - test: branch1
   Hop we are done.
 
   $ hg status
   M a
   ? a.orig
 
 Verify custom conflict markers
 
   $ hg up -q --clean .
   $ printf "\n[ui]\nmergemarkertemplate={author} {rev}\n" >> .hg/hgrc
 
   $ hg merge 1
   merging a
   warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
   0 files updated, 0 files merged, 0 files removed, 1 files unresolved
   use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
   [1]
 
   $ cat a
   Small Mathematical Series.
-  <<<<<<< local: test 2
   1
   2
   3
+  <<<<<<< local: test 2
   6
   8
   =======
-  1
-  2
-  3
   4
   5
   >>>>>>> other: test 1
   Hop we are done.
 
 Verify line splitting of custom conflict marker which causes multiple lines
 
   $ hg up -q --clean .
   $ cat >> .hg/hgrc <<EOF
   > [ui]
   > mergemarkertemplate={author} {rev}\nfoo\nbar\nbaz
   > EOF
 
   $ hg -q merge 1
   warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
   [1]
 
   $ cat a
   Small Mathematical Series.
-  <<<<<<< local: test 2
   1
   2
   3
+  <<<<<<< local: test 2
   6
   8
   =======
-  1
-  2
-  3
   4
   5
   >>>>>>> other: test 1
   Hop we are done.
 
 Verify line trimming of custom conflict marker using multi-byte characters
 
   $ hg up -q --clean .
   $ python <<EOF
   > fp = open('logfile', 'w')
   > fp.write('12345678901234567890123456789012345678901234567890' +
   >          '1234567890') # there are 5 more columns for 80 columns
   > 
   > # 2 x 4 = 8 columns, but 3 x 4 = 12 bytes
   > fp.write(u'\u3042\u3044\u3046\u3048'.encode('utf-8'))
   > 
   > fp.close()
   > EOF
   $ hg add logfile
   $ hg --encoding utf-8 commit --logfile logfile
 
   $ cat >> .hg/hgrc <<EOF
   > [ui]
   > mergemarkertemplate={desc|firstline}
   > EOF
 
   $ hg -q --encoding utf-8 merge 1
   warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
   [1]
 
   $ cat a
   Small Mathematical Series.
-  <<<<<<< local: 123456789012345678901234567890123456789012345678901234567890\xe3\x81\x82... (esc)
   1
   2
   3
+  <<<<<<< local: 123456789012345678901234567890123456789012345678901234567890\xe3\x81\x82... (esc)
   6
   8
   =======
-  1
-  2
-  3
   4
   5
   >>>>>>> other: branch1
   Hop we are done.
 
 Verify basic conflict markers
 
   $ hg up -q --clean 2
   $ printf "\n[ui]\nmergemarkers=basic\n" >> .hg/hgrc
 
   $ hg merge 1
   merging a
   warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
   0 files updated, 0 files merged, 0 files removed, 1 files unresolved
   use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
   [1]
 
   $ cat a
   Small Mathematical Series.
-  <<<<<<< local
   1
   2
   3
+  <<<<<<< local
   6
   8
   =======
-  1
-  2
-  3
   4
   5
   >>>>>>> other
   Hop we are done.
 
 internal:merge3
 
   $ hg up -q --clean .
 
   $ hg merge 1 --tool internal:merge3
   merging a
   warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
   0 files updated, 0 files merged, 0 files removed, 1 files unresolved
   use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
   [1]
   $ cat a
   Small Mathematical Series.
   <<<<<<< local
   1
   2
   3
   6
   8
   ||||||| base
   One
   Two
   Three
   Four
   Five
   =======
   1
   2
   3
   4
   5
   >>>>>>> other
   Hop we are done.
 
 Add some unconflicting changes on each head, to make sure we really
 are merging, unlike :local and :other
 
   $ hg up -C
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   1 other heads for branch "default"
   $ printf "\n\nEnd of file\n" >> a
   $ hg ci -m "Add some stuff at the end"
   $ hg up -r 1
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ printf "Start of file\n\n\n" > tmp
   $ cat a >> tmp
   $ mv tmp a
   $ hg ci -m "Add some stuff at the beginning"
 
 Now test :merge-other and :merge-local
 
   $ hg merge
   merging a
   warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
   1 files updated, 0 files merged, 0 files removed, 1 files unresolved
   use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
   [1]
   $ hg resolve --tool :merge-other a
   merging a
   (no more unresolved files)
   $ cat a
   Start of file
   
   
   Small Mathematical Series.
   1
   2
   3
   6
   8
   Hop we are done.
   
   
   End of file
 
   $ hg up -C
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   1 other heads for branch "default"
   $ hg merge --tool :merge-local
   merging a
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ cat a
   Start of file
   
   
   Small Mathematical Series.
   1
   2
   3
   4
   5
   Hop we are done.
   
   
   End of file

tests/test-contrib.t

@@ -1,279 +1,276 b''
 Set vars:
 
   $ CONTRIBDIR="$TESTDIR/../contrib"
 
 Prepare repo-a:
 
   $ hg init repo-a
   $ cd repo-a
 
   $ echo this is file a > a
   $ hg add a
   $ hg commit -m first
 
   $ echo adding to file a >> a
   $ hg commit -m second
 
   $ echo adding more to file a >> a
   $ hg commit -m third
 
   $ hg verify
   checking changesets
   checking manifests
   crosschecking files in changesets and manifests
   checking files
   1 files, 3 changesets, 3 total revisions
 
 Dumping revlog of file a to stdout:
 
   $ python "$CONTRIBDIR/dumprevlog" .hg/store/data/a.i
   file: .hg/store/data/a.i
   node: 183d2312b35066fb6b3b449b84efc370d50993d0
   linkrev: 0
   parents: 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000
   length: 15
   -start-
   this is file a
   
   -end-
   node: b1047953b6e6b633c0d8197eaa5116fbdfd3095b
   linkrev: 1
   parents: 183d2312b35066fb6b3b449b84efc370d50993d0 0000000000000000000000000000000000000000
   length: 32
   -start-
   this is file a
   adding to file a
   
   -end-
   node: 8c4fd1f7129b8cdec6c7f58bf48fb5237a4030c1
   linkrev: 2
   parents: b1047953b6e6b633c0d8197eaa5116fbdfd3095b 0000000000000000000000000000000000000000
   length: 54
   -start-
   this is file a
   adding to file a
   adding more to file a
   
   -end-
 
 Dump all revlogs to file repo.dump:
 
   $ find .hg/store -name "*.i" | sort | xargs python "$CONTRIBDIR/dumprevlog" > ../repo.dump
   $ cd ..
 
 Undumping into repo-b:
 
   $ hg init repo-b
   $ cd repo-b
   $ python "$CONTRIBDIR/undumprevlog" < ../repo.dump
   .hg/store/00changelog.i
   .hg/store/00manifest.i
   .hg/store/data/a.i
   $ cd ..
 
 Rebuild fncache with clone --pull:
 
   $ hg clone --pull -U repo-b repo-c
   requesting all changes
   adding changesets
   adding manifests
   adding file changes
   added 3 changesets with 3 changes to 1 files
 
 Verify:
 
   $ hg -R repo-c verify
   checking changesets
   checking manifests
   crosschecking files in changesets and manifests
   checking files
   1 files, 3 changesets, 3 total revisions
 
 Compare repos:
 
   $ hg -R repo-c incoming repo-a
   comparing with repo-a
   searching for changes
   no changes found
   [1]
 
   $ hg -R repo-a incoming repo-c
   comparing with repo-c
   searching for changes
   no changes found
   [1]
 
 Test simplemerge command:
 
   $ cp "$CONTRIBDIR/simplemerge" .
   $ echo base > base
   $ echo local > local
   $ cat base >> local
   $ cp local orig
   $ cat base > other
   $ echo other >> other
 
 changing local directly
 
   $ python simplemerge local base other && echo "merge succeeded"
   merge succeeded
   $ cat local
   local
   base
   other
   $ cp orig local
 
 printing to stdout
 
   $ python simplemerge -p local base other
   local
   base
   other
 
 local:
 
   $ cat local
   local
   base
 
 conflicts
 
   $ cp base conflict-local
   $ cp other conflict-other
   $ echo not other >> conflict-local
   $ echo end >> conflict-local
   $ echo end >> conflict-other
 
   $ python simplemerge -p conflict-local base conflict-other
   base
   <<<<<<< conflict-local
   not other
-  end
   =======
   other
+  >>>>>>> conflict-other
   end
-  >>>>>>> conflict-other
   [1]
 
 1 label
 
   $ python simplemerge -p -L foo conflict-local base conflict-other
   base
   <<<<<<< foo
   not other
-  end
   =======
   other
+  >>>>>>> conflict-other
   end
-  >>>>>>> conflict-other
   [1]
 
 2 labels
 
   $ python simplemerge -p -L foo -L bar conflict-local base conflict-other
   base
   <<<<<<< foo
   not other
-  end
   =======
   other
+  >>>>>>> bar
   end
-  >>>>>>> bar
   [1]
 
 3 labels
 
   $ python simplemerge -p -L foo -L bar -L base conflict-local base conflict-other
   base
   <<<<<<< foo
   not other
   end
   ||||||| base
   =======
   other
   end
   >>>>>>> bar
   [1]
 
 too many labels
 
   $ python simplemerge -p -L foo -L bar -L baz -L buz conflict-local base conflict-other
   abort: can only specify three labels.
   [255]
 
 binary file
 
   $ $PYTHON -c "f = file('binary-local', 'w'); f.write('\x00'); f.close()"
   $ cat orig >> binary-local
   $ python simplemerge -p binary-local base other
   warning: binary-local looks like a binary file.
   [1]
 
 binary file --text
 
   $ python simplemerge -a -p binary-local base other 2>&1
   warning: binary-local looks like a binary file.
   \x00local (esc)
   base
   other
 
 help
 
   $ python simplemerge --help
   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.
   
   options:
    -L --label       labels to use on conflict markers
    -a --text        treat all files as text
    -p --print       print results instead of overwriting LOCAL
       --no-minimal  no effect (DEPRECATED)
    -h --help        display help and exit
    -q --quiet       suppress output
 
 wrong number of arguments
 
   $ python simplemerge
   simplemerge: wrong number of arguments
   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.
   
   options:
    -L --label       labels to use on conflict markers
    -a --text        treat all files as text
    -p --print       print results instead of overwriting LOCAL
       --no-minimal  no effect (DEPRECATED)
    -h --help        display help and exit
    -q --quiet       suppress output
   [1]
 
 bad option
 
   $ python simplemerge --foo -p local base other
   simplemerge: option --foo not recognized
   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.
   
   options:
    -L --label       labels to use on conflict markers
    -a --text        treat all files as text
    -p --print       print results instead of overwriting LOCAL
       --no-minimal  no effect (DEPRECATED)
    -h --help        display help and exit
    -q --quiet       suppress output
   [1]

tests/test-rebase-conflicts.t

@@ -1,307 +1,359 b''
   $ cat >> $HGRCPATH <<EOF
   > [format]
   > usegeneraldelta=yes
   > [extensions]
   > rebase=
   > 
   > [phases]
   > publish=False
   > 
   > [alias]
   > tglog = log -G --template "{rev}:{phase} '{desc}' {branches} {bookmarks}\n"
   > EOF
 
   $ hg init a
   $ cd a
   $ echo c1 >common
   $ hg add common
   $ hg ci -m C1
 
   $ echo c2 >>common
   $ hg ci -m C2
 
   $ echo c3 >>common
   $ hg ci -m C3
 
   $ hg up -q -C 1
 
   $ echo l1 >>extra
   $ hg add extra
   $ hg ci -m L1
   created new head
 
   $ sed -e 's/c2/l2/' common > common.new
   $ mv common.new common
   $ hg ci -m L2
 
   $ echo l3 >> extra2
   $ hg add extra2
   $ hg ci -m L3
   $ hg bookmark mybook
 
   $ hg phase --force --secret 4
 
   $ hg tglog
   @  5:secret 'L3'  mybook
   |
   o  4:secret 'L2'
   |
   o  3:draft 'L1'
   |
   | o  2:draft 'C3'
   |/
   o  1:draft 'C2'
   |
   o  0:draft 'C1'
   
 Try to call --continue:
 
   $ hg rebase --continue
   abort: no rebase in progress
   [255]
 
 Conflicting rebase:
 
   $ hg rebase -s 3 -d 2
   rebasing 3:3163e20567cc "L1"
   rebasing 4:46f0b057b5c0 "L2"
   merging common
   warning: conflicts while merging common! (edit, then use 'hg resolve --mark')
   unresolved conflicts (see hg resolve, then hg rebase --continue)
   [1]
 
 Try to continue without solving the conflict:
 
   $ hg rebase --continue
   already rebased 3:3163e20567cc "L1" as 3e046f2ecedb
   rebasing 4:46f0b057b5c0 "L2"
   abort: unresolved merge conflicts (see "hg help resolve")
   [255]
 
 Conclude rebase:
 
   $ echo 'resolved merge' >common
   $ hg resolve -m common
   (no more unresolved files)
   continue: hg rebase --continue
   $ hg rebase --continue
   already rebased 3:3163e20567cc "L1" as 3e046f2ecedb
   rebasing 4:46f0b057b5c0 "L2"
   rebasing 5:8029388f38dc "L3" (mybook)
   saved backup bundle to $TESTTMP/a/.hg/strip-backup/3163e20567cc-5ca4656e-backup.hg (glob)
 
   $ hg tglog
   @  5:secret 'L3'  mybook
   |
   o  4:secret 'L2'
   |
   o  3:draft 'L1'
   |
   o  2:draft 'C3'
   |
   o  1:draft 'C2'
   |
   o  0:draft 'C1'
   
 Check correctness:
 
   $ hg cat -r 0 common
   c1
 
   $ hg cat -r 1 common
   c1
   c2
 
   $ hg cat -r 2 common
   c1
   c2
   c3
 
   $ hg cat -r 3 common
   c1
   c2
   c3
 
   $ hg cat -r 4 common
   resolved merge
 
   $ hg cat -r 5 common
   resolved merge
 
 Bookmark stays active after --continue
   $ hg bookmarks
    * mybook                    5:d67b21408fc0
 
   $ cd ..
 
 Check that the right ancestors is used while rebasing a merge (issue4041)
 
   $ hg clone "$TESTDIR/bundles/issue4041.hg" issue4041
   requesting all changes
   adding changesets
   adding manifests
   adding file changes
   added 11 changesets with 8 changes to 3 files (+1 heads)
   updating to branch default
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd issue4041
   $ hg log -G
   o    changeset:   10:2f2496ddf49d
   |\   branch:      f1
   | |  tag:         tip
   | |  parent:      7:4c9fbe56a16f
   | |  parent:      9:e31216eec445
   | |  user:        szhang
   | |  date:        Thu Sep 05 12:59:39 2013 -0400
   | |  summary:     merge
   | |
   | o  changeset:   9:e31216eec445
   | |  branch:      f1
   | |  user:        szhang
   | |  date:        Thu Sep 05 12:59:10 2013 -0400
   | |  summary:     more changes to f1
   | |
   | o    changeset:   8:8e4e2c1a07ae
   | |\   branch:      f1
   | | |  parent:      2:4bc80088dc6b
   | | |  parent:      6:400110238667
   | | |  user:        szhang
   | | |  date:        Thu Sep 05 12:57:59 2013 -0400
   | | |  summary:     bad merge
   | | |
   o | |  changeset:   7:4c9fbe56a16f
   |/ /   branch:      f1
   | |    parent:      2:4bc80088dc6b
   | |    user:        szhang
   | |    date:        Thu Sep 05 12:54:00 2013 -0400
   | |    summary:     changed f1
   | |
   | o  changeset:   6:400110238667
   | |  branch:      f2
   | |  parent:      4:12e8ec6bb010
   | |  user:        szhang
   | |  date:        Tue Sep 03 13:58:02 2013 -0400
   | |  summary:     changed f2 on f2
   | |
   | | @  changeset:   5:d79e2059b5c0
   | | |  parent:      3:8a951942e016
   | | |  user:        szhang
   | | |  date:        Tue Sep 03 13:57:39 2013 -0400
   | | |  summary:     changed f2 on default
   | | |
   | o |  changeset:   4:12e8ec6bb010
   | |/   branch:      f2
   | |    user:        szhang
   | |    date:        Tue Sep 03 13:57:18 2013 -0400
   | |    summary:     created f2 branch
   | |
   | o  changeset:   3:8a951942e016
   | |  parent:      0:24797d4f68de
   | |  user:        szhang
   | |  date:        Tue Sep 03 13:57:11 2013 -0400
   | |  summary:     added f2.txt
   | |
   o |  changeset:   2:4bc80088dc6b
   | |  branch:      f1
   | |  user:        szhang
   | |  date:        Tue Sep 03 13:56:20 2013 -0400
   | |  summary:     added f1.txt
   | |
   o |  changeset:   1:ef53c9e6b608
   |/   branch:      f1
   |    user:        szhang
   |    date:        Tue Sep 03 13:55:26 2013 -0400
   |    summary:     created f1 branch
   |
   o  changeset:   0:24797d4f68de
      user:        szhang
      date:        Tue Sep 03 13:55:08 2013 -0400
      summary:     added default.txt
   
   $ hg rebase -s9 -d2 --debug # use debug to really check merge base used
   rebase onto 2 starting from e31216eec445
   ignoring null merge rebase of 3
   ignoring null merge rebase of 4
   ignoring null merge rebase of 6
   ignoring null merge rebase of 8
   rebasing 9:e31216eec445 "more changes to f1"
    future parents are 2 and -1
   rebase status stored
    update to 2:4bc80088dc6b
   resolving manifests
    branchmerge: False, force: True, partial: False
    ancestor: d79e2059b5c0+, local: d79e2059b5c0+, remote: 4bc80088dc6b
    f2.txt: other deleted -> r
   removing f2.txt
    f1.txt: remote created -> g
   getting f1.txt
    merge against 9:e31216eec445
      detach base 8:8e4e2c1a07ae
     searching for copies back to rev 3
   resolving manifests
    branchmerge: True, force: True, partial: False
    ancestor: 8e4e2c1a07ae, local: 4bc80088dc6b+, remote: e31216eec445
    f1.txt: remote is newer -> g
   getting f1.txt
   committing files:
   f1.txt
   committing manifest
   committing changelog
   rebased as 19c888675e13
   rebasing 10:2f2496ddf49d "merge" (tip)
    future parents are 11 and 7
   rebase status stored
    already in target
    merge against 10:2f2496ddf49d
      detach base 9:e31216eec445
     searching for copies back to rev 3
   resolving manifests
    branchmerge: True, force: True, partial: False
    ancestor: e31216eec445, local: 19c888675e13+, remote: 2f2496ddf49d
    f1.txt: remote is newer -> g
   getting f1.txt
   committing files:
   f1.txt
   committing manifest
   committing changelog
   rebased as 2a7f09cac94c
   rebase merging completed
   update back to initial working directory parent
   resolving manifests
    branchmerge: False, force: False, partial: False
    ancestor: 2a7f09cac94c, local: 2a7f09cac94c+, remote: d79e2059b5c0
    f1.txt: other deleted -> r
   removing f1.txt
    f2.txt: remote created -> g
   getting f2.txt
   2 changesets found
   list of changesets:
   e31216eec445e44352c5f01588856059466a24c9
   2f2496ddf49d69b5ef23ad8cf9fb2e0e4faf0ac2
   bundle2-output-bundle: "HG20", (1 params) 1 parts total
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
   saved backup bundle to $TESTTMP/issue4041/.hg/strip-backup/e31216eec445-15f7a814-backup.hg (glob)
   3 changesets found
   list of changesets:
   4c9fbe56a16f30c0d5dcc40ec1a97bbe3325209c
   19c888675e133ab5dff84516926a65672eaf04d9
   2a7f09cac94c7f4b73ebd5cd1a62d3b2e8e336bf
   bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
   adding branch
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "changegroup" (params: 1 mandatory) supported
   adding changesets
   add changeset 4c9fbe56a16f
   add changeset 19c888675e13
   add changeset 2a7f09cac94c
   adding manifests
   adding file changes
   adding f1.txt revisions
   added 2 changesets with 2 changes to 1 files
   bundle2-input-part: total payload size 1713
   bundle2-input-bundle: 0 parts total
   invalid branchheads cache (served): tip differs
   rebase completed
   updating the branch cache
   truncating cache/rbc-revs-v1 to 72
+
+Test minimization of merge conflicts
+  $ hg up -q null
+  $ echo a > a
+  $ hg add a
+  $ hg commit -q -m 'a'
+  $ echo b >> a
+  $ hg commit -q -m 'ab'
+  $ hg bookmark ab
+  $ hg up -q '.^'
+  $ echo b >> a
+  $ echo c >> a
+  $ hg commit -q -m 'abc'
+  $ hg rebase -s 7bc217434fc1 -d ab --keep
+  rebasing 13:7bc217434fc1 "abc" (tip)
+  merging a
+  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
+  unresolved conflicts (see hg resolve, then hg rebase --continue)
+  [1]
+  $ hg diff
+  diff -r 328e4ab1f7cc a
+  --- a/a	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/a	* (glob)
+  @@ -1,2 +1,6 @@
+   a
+   b
+  +<<<<<<< dest:   328e4ab1f7cc  ab - test: ab
+  +=======
+  +c
+  +>>>>>>> source: 7bc217434fc1 - test: abc
+  $ hg rebase --abort
+  rebase aborted
+  $ hg up -q -C 7bc217434fc1
+  $ hg rebase -s . -d ab --keep -t internal:merge3
+  rebasing 13:7bc217434fc1 "abc" (tip)
+  merging a
+  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
+  unresolved conflicts (see hg resolve, then hg rebase --continue)
+  [1]
+  $ hg diff
+  diff -r 328e4ab1f7cc a
+  --- a/a	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/a	* (glob)
+  @@ -1,2 +1,8 @@
+   a
+  +<<<<<<< dest:   328e4ab1f7cc  ab - test: ab
+   b
+  +||||||| base
+  +=======
+  +b
+  +c
+  +>>>>>>> source: 7bc217434fc1 - test: abc