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Viewing changes to bzrlib/tests/test_merge.py

Committer: John Arbash Meinel
Date: 2008-07-10 22:41:46 UTC
mto: This revision was merged to the branch mainline in revision 3543.
Revision ID: john@arbash-meinel.com-20080710224146-pmkkzgc4vbxhgrsr

The insertion ordering into the weave has an impact on conflicts.

Basically, when A has ancestors B and C which have overlapping changes,
inserting B before C will implicitly sort its lines earlier in the weave.
If A resolves the conflict by preserving this ordering, then switching that
ordering later will make those lines look like they originated in A, rather
than in B and C. (Because diff can't track moved lines yet.)

So bring in some explicit ordering constraints which are likely to fit the
real world workflow. Specifically, prefer to add the left-hand parents before
the right-hand parents. Since that is how the merge was done.

files modified:
bzrlib/graph.py

bzrlib/merge.py

bzrlib/tests/test_graph.py

bzrlib/tests/test_merge.py

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added added

removed removed

bzrlib/tests/test_merge.py

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('unchanged', 'a\n'),

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('killed-a', 'b\n'),

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('killed-b', 'c\n'),

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('new-b', 'g\n'),

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('new-a', 'e\n'),

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('new-a', 'h\n'),

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('new-a', 'g\n')],

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('new-a', 'g\n'),

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('new-b', 'g\n')],

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list(plan))

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def test_plan_merge_cherrypick(self):

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self.add_version(('root', 'B'), [], 'xyz')

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my_plan = _PlanMerge('A', 'B', self.plan_merge_vf, ('root',))

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self.assertEqual([

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('new-a', 'a\n'),

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('new-a', 'b\n'),

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('new-a', 'c\n'),

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('new-b', 'x\n'),

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('new-b', 'y\n'),

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('new-b', 'z\n'),

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('new-a', 'a\n'),

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('new-a', 'b\n'),

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('new-a', 'c\n')],

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('new-b', 'z\n')],

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list(my_plan.plan_merge()))

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def test_plan_merge_uncommitted_files(self):

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('unchanged', 'a\n'),

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('killed-a', 'b\n'),

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('killed-b', 'c\n'),

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('new-b', 'g\n'),

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('new-a', 'e\n'),

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('new-a', 'h\n'),

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('new-a', 'g\n')],

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('new-a', 'g\n'),

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('new-b', 'g\n')],

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list(plan))

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def test_plan_merge_insert_order(self):

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"""Weave merges are sensitive to the order of insertion.

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Specifically for overlapping regions, it effects which region gets put

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'first'. And when a user resolves an overlapping merge, if they use the

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same ordering, then the lines match the parents, if they don't only

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*some* of the lines match.

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"""

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self.add_version(('root', 'A'), [], 'abcdef')

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self.add_version(('root', 'B'), [('root', 'A')], 'abwxcdef')

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self.add_version(('root', 'C'), [('root', 'A')], 'abyzcdef')

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# Merge, and resolve the conflict by adding *both* sets of lines

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# If we get the ordering wrong, these will look like new lines in D,

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# rather than carried over from B, C

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self.add_version(('root', 'D'), [('root', 'B'), ('root', 'C')],

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'abwxyzcdef')

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# Supersede the lines in B and delete the lines in C, which will

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# conflict if they are treated as being in D

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self.add_version(('root', 'E'), [('root', 'C'), ('root', 'B')],

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'abnocdef')

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# Same thing for the lines in C

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self.add_version(('root', 'F'), [('root', 'C')], 'abpqcdef')

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plan = self.plan_merge_vf.plan_merge('D', 'E')

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self.assertEqual([

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('unchanged', 'a\n'),

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('unchanged', 'b\n'),

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('killed-b', 'w\n'),

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('killed-b', 'x\n'),

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('killed-b', 'y\n'),

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('killed-b', 'z\n'),

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('new-b', 'n\n'),

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('new-b', 'o\n'),

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('unchanged', 'c\n'),

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('unchanged', 'd\n'),

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('unchanged', 'e\n'),

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('unchanged', 'f\n')],

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list(plan))

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plan = self.plan_merge_vf.plan_merge('E', 'D')

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# Going in the opposite direction shows the effect of the opposite plan

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self.assertEqual([

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('unchanged', 'a\n'),

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('unchanged', 'b\n'),

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('new-b', 'w\n'),

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('new-b', 'x\n'),

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('killed-a', 'y\n'),

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('killed-a', 'z\n'),

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('killed-both', 'w\n'),

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('killed-both', 'x\n'),

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('new-a', 'n\n'),

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('new-a', 'o\n'),

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('unchanged', 'c\n'),

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('unchanged', 'd\n'),

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('unchanged', 'e\n'),

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('unchanged', 'f\n')],

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list(plan))

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def test_plan_merge_criss_cross(self):

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# This is specificly trying to trigger problems when using limited

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# ancestry and weaves. The ancestry graph looks like:

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# XX unused ancestor, should not show up in the weave

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# |

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# A Unique LCA

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# |\

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# B \ Introduces a line 'foo'

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# 'foo', it should appear as superseding the value in F (since it

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# came from B), rather than conflict because of the resolution during

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# C & D.

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self.add_version(('root', 'A'), [], 'abcdef')

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self.add_version(('root', 'XX'), [], 'qrs')

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self.add_version(('root', 'A'), [('root', 'XX')], 'abcdef')

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self.add_version(('root', 'B'), [('root', 'A')], 'axcdef')

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self.add_version(('root', 'C'), [('root', 'B')], 'axcdefg')

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self.add_version(('root', 'D'), [('root', 'B')], 'haxcdef')

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