Mercurial > hg
view tests/test-linerange.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 | ee3a55c8fd0f |
children | 6000f5b25c9b |
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from __future__ import absolute_import import unittest from mercurial import error, mdiff from mercurial.utils import stringutil # 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( b'line range exceeds file size' in stringutil.forcebytestr(exc) ) else: self.fail('%s not raised' % exctype.__name__) if __name__ == '__main__': import silenttestrunner silenttestrunner.main(__name__)