view tests/test-linerange.py @ 42619:20d0e59be79b

tests: show the files fields of changelogs for many merges

I don't think there's coverage for many of the subtle cases, and I
found it hard to understand what the code is doing by reading it.  The
test takes 40s to run on a laptop, or 9s with --chg.

I have yet to find a description of what the files field is supposed
to be for merges. I thought it could be one of:
1. the files added/modified/removed relative to p1 (wouldn't seem
  useful, but `hg diff -c -r mergerev` has this behavior)
2. the files with filelog nodes not in either parent (i.e., what is
needed to create a bundle out of a commit)
3. the files added/removed/modified files by merge itself [1]

It's clearly not 1, because file contents merges are symmetric. It's
clearly not 2 because removed files and exec bit changes are
listed. It's also not 3 but I think it's intended to be 3 and the
differences are bugs.

Assuming 3, the test shows that, for merges, the list of files both
overapproximates and underapproximates. All the cases involve file
changes not in the filelog but in the manifest (existence of file
at revision, exec bit and file vs symlink).

I didn't look at all underapproximations, but they looked minor. The
two overapproximations are problematic though because they both cause
potentially long lists of files when merging cleanly.


[1] even what it means for the merge commit itself to change a file is
not completely trivial. A file in the merge being the same as in one
of the parent is too lax as it would consider that merges change
nothing when they revert all the changes done on one side. The
criteria used in the test and in the next commit for "merge didn't
touch a file" is:
- the parents and the merge all have the same file
- or, one parent didn't touch the file and the other parent contains
  the same file as the merge

Differential Revision: https://phab.mercurial-scm.org/D6612

from __future__ import absolute_import

import unittest
from mercurial import error, mdiff

# for readability, line numbers are 0-origin
text1 = b'''
           00 at OLD
           01 at OLD
           02 at OLD
02 at NEW, 03 at OLD
03 at NEW, 04 at OLD
04 at NEW, 05 at OLD
05 at NEW, 06 at OLD
           07 at OLD
           08 at OLD
           09 at OLD
           10 at OLD
           11 at OLD
'''[1:] # strip initial LF

text2 = b'''
00 at NEW
01 at NEW
02 at NEW, 03 at OLD
03 at NEW, 04 at OLD
04 at NEW, 05 at OLD
05 at NEW, 06 at OLD
06 at NEW
07 at NEW
08 at NEW
09 at NEW
10 at NEW
11 at NEW
'''[1:] # strip initial LF

def filteredblocks(blocks, rangeb):
    """return `rangea` extracted from `blocks` coming from
    `mdiff.blocksinrange` along with the mask of blocks within rangeb.
    """
    filtered, rangea = mdiff.blocksinrange(blocks, rangeb)
    skipped = [b not in filtered for b in blocks]
    return rangea, skipped

class blocksinrangetests(unittest.TestCase):

    def setUp(self):
        self.blocks = list(mdiff.allblocks(text1, text2))
        assert self.blocks == [
            ([0, 3, 0, 2], b'!'),
            ((3, 7, 2, 6), b'='),
            ([7, 12, 6, 12], b'!'),
            ((12, 12, 12, 12), b'='),
        ], self.blocks

    def testWithinEqual(self):
        """linerange within an "=" block"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #        ^^
        linerange2 = (3, 5)
        linerange1, skipped = filteredblocks(self.blocks, linerange2)
        self.assertEqual(linerange1, (4, 6))
        self.assertEqual(skipped, [True, False, True, True])

    def testWithinEqualStrictly(self):
        """linerange matching exactly an "=" block"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #       ^^^^
        linerange2 = (2, 6)
        linerange1, skipped = filteredblocks(self.blocks, linerange2)
        self.assertEqual(linerange1, (3, 7))
        self.assertEqual(skipped, [True, False, True, True])

    def testWithinEqualLowerbound(self):
        """linerange at beginning of an "=" block"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #       ^^
        linerange2 = (2, 4)
        linerange1, skipped = filteredblocks(self.blocks, linerange2)
        self.assertEqual(linerange1, (3, 5))
        self.assertEqual(skipped, [True, False, True, True])

    def testWithinEqualLowerboundOneline(self):
        """oneline-linerange at beginning of an "=" block"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #       ^
        linerange2 = (2, 3)
        linerange1, skipped = filteredblocks(self.blocks, linerange2)
        self.assertEqual(linerange1, (3, 4))
        self.assertEqual(skipped, [True, False, True, True])

    def testWithinEqualUpperbound(self):
        """linerange at end of an "=" block"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #        ^^^
        linerange2 = (3, 6)
        linerange1, skipped = filteredblocks(self.blocks, linerange2)
        self.assertEqual(linerange1, (4, 7))
        self.assertEqual(skipped, [True, False, True, True])

    def testWithinEqualUpperboundOneLine(self):
        """oneline-linerange at end of an "=" block"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #          ^
        linerange2 = (5, 6)
        linerange1, skipped = filteredblocks(self.blocks, linerange2)
        self.assertEqual(linerange1, (6, 7))
        self.assertEqual(skipped, [True, False, True, True])

    def testWithinFirstBlockNeq(self):
        """linerange within the first "!" block"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #     ^
        #      |           (empty)
        #      ^
        #     ^^
        for linerange2 in [
            (0, 1),
            (1, 1),
            (1, 2),
            (0, 2),
        ]:
            linerange1, skipped = filteredblocks(self.blocks, linerange2)
            self.assertEqual(linerange1, (0, 3))
            self.assertEqual(skipped, [False, True, True, True])

    def testWithinLastBlockNeq(self):
        """linerange within the last "!" block"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #           ^
        #            ^
        #           |      (empty)
        #           ^^^^^^
        #                ^
        for linerange2 in [
            (6, 7),
            (7, 8),
            (7, 7),
            (6, 12),
            (11, 12),
        ]:
            linerange1, skipped = filteredblocks(self.blocks, linerange2)
            self.assertEqual(linerange1, (7, 12))
            self.assertEqual(skipped, [True, True, False, True])

    def testAccrossTwoBlocks(self):
        """linerange accross two blocks"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #      ^^^^
        linerange2 = (1, 5)
        linerange1, skipped = filteredblocks(self.blocks, linerange2)
        self.assertEqual(linerange1, (0, 6))
        self.assertEqual(skipped, [False, False, True, True])

    def testCrossingSeveralBlocks(self):
        """linerange accross three blocks"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #      ^^^^^^^
        linerange2 = (1, 8)
        linerange1, skipped = filteredblocks(self.blocks, linerange2)
        self.assertEqual(linerange1, (0, 12))
        self.assertEqual(skipped, [False, False, False, True])

    def testStartInEqBlock(self):
        """linerange starting in an "=" block"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #          ^^^^
        #         ^^^^^^^
        for linerange2, expectedlinerange1 in [
            ((5, 9), (6, 12)),
            ((4, 11), (5, 12)),
        ]:
            linerange1, skipped = filteredblocks(self.blocks, linerange2)
            self.assertEqual(linerange1, expectedlinerange1)
            self.assertEqual(skipped, [True, False, False, True])

    def testEndInEqBlock(self):
        """linerange ending in an "=" block"""
        # IDX 0         1
        #     012345678901
        # SRC NNOOOONNNNNN (New/Old)
        #      ^^
        #     ^^^^^
        for linerange2, expectedlinerange1 in [
            ((1, 3), (0, 4)),
            ((0, 4), (0, 5)),
        ]:
            linerange1, skipped = filteredblocks(self.blocks, linerange2)
            self.assertEqual(linerange1, expectedlinerange1)
            self.assertEqual(skipped, [False, False, True, True])

    def testOutOfRange(self):
        """linerange exceeding file size"""
        exctype = error.Abort
        for linerange2 in [
            (0, 34),
            (15, 12),
        ]:
            # Could be `with self.assertRaises(error.Abort)` but python2.6
            # does not have assertRaises context manager.
            try:
                mdiff.blocksinrange(self.blocks, linerange2)
            except exctype as exc:
                self.assertTrue('line range exceeds file size' in str(exc))
            else:
                self.fail('%s not raised' % exctype.__name__)

if __name__ == '__main__':
    import silenttestrunner
    silenttestrunner.main(__name__)