Mercurial > hg
view tests/test-absorb-filefixupstate.py @ 49000:dd6b67d5c256 stable
rust: fix unsound `OwningDirstateMap`
As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.
The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.
I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.
In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.
Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.
Differential Revision: https://phab.mercurial-scm.org/D12429
author | Raphaël Gomès <rgomes@octobus.net> |
---|---|
date | Tue, 05 Apr 2022 10:55:28 +0200 |
parents | 89a2afe31e82 |
children | 6000f5b25c9b |
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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)