view tests/test-absorb-filefixupstate.py @ 42743:8c9a6adec67a

rust-discovery: using the children cache in add_missing

The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.

The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.

This is a case where staying on the same side of the interface
between the two languages has clear benefits.

On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.

For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:

Rust version with simple iteration
  addcommons: 57.287us
  first undecided computation: 184.278334ms
  first children cache computation: 131.056us
  addmissings iteration: 42.766us
  first addinfo total: 185.24 ms

Python + C version
  first addcommons: 0.29 ms
  addcommons 0.21 ms
  first undecided computation 191.35 ms
  addmissings 45.75 ms
  first addinfo total: 237.77 ms

On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:

Rust version:
  first undecided computation: 293.842629ms
  first children cache computation: 407.911297ms
  addmissings iteration: 34.312869ms
  first addinfo total: 776.02 ms
  taking initial sample
  query 2: sampling time: 1318.38 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings: 143.062us

Python + C version:
  first undecided computation 298.13 ms
  addmissings 80.13 ms
  first addinfo total: 399.62 ms
  taking initial sample
  query 2: sampling time: 3957.23 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings 52.88 ms

Differential Revision: https://phab.mercurial-scm.org/D6428

from __future__ import absolute_import, print_function

import itertools
from mercurial import pycompat
from hgext import absorb

class simplefctx(object):
    def __init__(self, content):
        self.content = content

    def data(self):
        return self.content

def insertreturns(x):
    # insert "\n"s after each single char
    if isinstance(x, bytes):
        return b''.join(ch + b'\n' for ch in pycompat.bytestr(x))
    else:
        return pycompat.maplist(insertreturns, x)

def removereturns(x):
    # the revert of "insertreturns"
    if isinstance(x, bytes):
        return x.replace(b'\n', b'')
    else:
        return pycompat.maplist(removereturns, x)

def assertlistequal(lhs, rhs, decorator=lambda x: x):
    if lhs != rhs:
        raise RuntimeError('mismatch:\n actual:   %r\n expected: %r'
                           % tuple(map(decorator, [lhs, rhs])))

def testfilefixup(oldcontents, workingcopy, expectedcontents, fixups=None):
    """([str], str, [str], [(rev, a1, a2, b1, b2)]?) -> None

    workingcopy is a string, of which every character denotes a single line.

    oldcontents, expectedcontents are lists of strings, every character of
    every string denots a single line.

    if fixups is not None, it's the expected fixups list and will be checked.
    """
    expectedcontents = insertreturns(expectedcontents)
    oldcontents = insertreturns(oldcontents)
    workingcopy = insertreturns(workingcopy)
    state = absorb.filefixupstate(pycompat.maplist(simplefctx, oldcontents),
                                  'path')
    state.diffwith(simplefctx(workingcopy))
    if fixups is not None:
        assertlistequal(state.fixups, fixups)
    state.apply()
    assertlistequal(state.finalcontents, expectedcontents, removereturns)

def buildcontents(linesrevs):
    # linesrevs: [(linecontent : str, revs : [int])]
    revs = set(itertools.chain(*[revs for line, revs in linesrevs]))
    return [b''] + [
        b''.join([l for l, rs in linesrevs if r in rs])
        for r in sorted(revs)
    ]

# input case 0: one single commit
case0 = [b'', b'11']

# replace a single chunk
testfilefixup(case0, b'', [b'', b''])
testfilefixup(case0, b'2', [b'', b'2'])
testfilefixup(case0, b'22', [b'', b'22'])
testfilefixup(case0, b'222', [b'', b'222'])

# input case 1: 3 lines, each commit adds one line
case1 = buildcontents([
    (b'1', [1, 2, 3]),
    (b'2', [   2, 3]),
    (b'3', [      3]),
])

# 1:1 line mapping
testfilefixup(case1, b'123', case1)
testfilefixup(case1, b'12c', [b'', b'1', b'12', b'12c'])
testfilefixup(case1, b'1b3', [b'', b'1', b'1b', b'1b3'])
testfilefixup(case1, b'1bc', [b'', b'1', b'1b', b'1bc'])
testfilefixup(case1, b'a23', [b'', b'a', b'a2', b'a23'])
testfilefixup(case1, b'a2c', [b'', b'a', b'a2', b'a2c'])
testfilefixup(case1, b'ab3', [b'', b'a', b'ab', b'ab3'])
testfilefixup(case1, b'abc', [b'', b'a', b'ab', b'abc'])

# non 1:1 edits
testfilefixup(case1, b'abcd', case1)
testfilefixup(case1, b'ab', case1)

# deletion
testfilefixup(case1, b'',   [b'', b'', b'', b''])
testfilefixup(case1, b'1',  [b'', b'1', b'1', b'1'])
testfilefixup(case1, b'2',  [b'', b'', b'2', b'2'])
testfilefixup(case1, b'3',  [b'', b'', b'', b'3'])
testfilefixup(case1, b'13', [b'', b'1', b'1', b'13'])

# replaces
testfilefixup(case1, b'1bb3', [b'', b'1', b'1bb', b'1bb3'])

# (confusing) replaces
testfilefixup(case1, b'1bbb', case1)
testfilefixup(case1, b'bbbb', case1)
testfilefixup(case1, b'bbb3', case1)
testfilefixup(case1, b'1b', case1)
testfilefixup(case1, b'bb', case1)
testfilefixup(case1, b'b3', case1)

# insertions at the beginning and the end
testfilefixup(case1, b'123c', [b'', b'1', b'12', b'123c'])
testfilefixup(case1, b'a123', [b'', b'a1', b'a12', b'a123'])

# (confusing) insertions
testfilefixup(case1, b'1a23', case1)
testfilefixup(case1, b'12b3', case1)

# input case 2: delete in the middle
case2 = buildcontents([
    (b'11', [1, 2]),
    (b'22', [1   ]),
    (b'33', [1, 2]),
])

# deletion (optimize code should make it 2 chunks)
testfilefixup(case2, b'', [b'', b'22', b''],
              fixups=[(4, 0, 2, 0, 0), (4, 2, 4, 0, 0)])

# 1:1 line mapping
testfilefixup(case2, b'aaaa', [b'', b'aa22aa', b'aaaa'])

# non 1:1 edits
# note: unlike case0, the chunk is not "continuous" and no edit allowed
testfilefixup(case2, b'aaa', case2)

# input case 3: rev 3 reverts rev 2
case3 = buildcontents([
    (b'1', [1, 2, 3]),
    (b'2', [   2   ]),
    (b'3', [1, 2, 3]),
])

# 1:1 line mapping
testfilefixup(case3, b'13', case3)
testfilefixup(case3, b'1b', [b'', b'1b', b'12b', b'1b'])
testfilefixup(case3, b'a3', [b'', b'a3', b'a23', b'a3'])
testfilefixup(case3, b'ab', [b'', b'ab', b'a2b', b'ab'])

# non 1:1 edits
testfilefixup(case3, b'a', case3)
testfilefixup(case3, b'abc', case3)

# deletion
testfilefixup(case3, b'', [b'', b'', b'2', b''])

# insertion
testfilefixup(case3, b'a13c', [b'', b'a13c', b'a123c', b'a13c'])

# input case 4: a slightly complex case
case4 = buildcontents([
    (b'1', [1, 2, 3]),
    (b'2', [   2, 3]),
    (b'3', [1, 2,  ]),
    (b'4', [1,    3]),
    (b'5', [      3]),
    (b'6', [   2, 3]),
    (b'7', [   2   ]),
    (b'8', [   2, 3]),
    (b'9', [      3]),
])

testfilefixup(case4, b'1245689', case4)
testfilefixup(case4, b'1a2456bbb', case4)
testfilefixup(case4, b'1abc5689', case4)
testfilefixup(case4, b'1ab5689', [b'', b'134', b'1a3678', b'1ab5689'])
testfilefixup(case4, b'aa2bcd8ee', [b'', b'aa34', b'aa23d78', b'aa2bcd8ee'])
testfilefixup(case4, b'aa2bcdd8ee',[b'', b'aa34', b'aa23678', b'aa24568ee'])
testfilefixup(case4, b'aaaaaa', case4)
testfilefixup(case4, b'aa258b', [b'', b'aa34', b'aa2378', b'aa258b'])
testfilefixup(case4, b'25bb', [b'', b'34', b'23678', b'25689'])
testfilefixup(case4, b'27', [b'', b'34', b'23678', b'245689'])
testfilefixup(case4, b'28', [b'', b'34', b'2378', b'28'])
testfilefixup(case4, b'', [b'', b'34', b'37', b''])

# input case 5: replace a small chunk which is near a deleted line
case5 = buildcontents([
    (b'12', [1, 2]),
    (b'3',  [1]),
    (b'4',  [1, 2]),
])

testfilefixup(case5, b'1cd4', [b'', b'1cd34', b'1cd4'])

# input case 6: base "changeset" is immutable
case6 = [b'1357', b'0125678']

testfilefixup(case6, b'0125678', case6)
testfilefixup(case6, b'0a25678', case6)
testfilefixup(case6, b'0a256b8', case6)
testfilefixup(case6, b'abcdefg', [b'1357', b'a1c5e7g'])
testfilefixup(case6, b'abcdef', case6)
testfilefixup(case6, b'', [b'1357', b'157'])
testfilefixup(case6, b'0123456789', [b'1357', b'0123456789'])

# input case 7: change an empty file
case7 = [b'']

testfilefixup(case7, b'1', case7)