Mercurial > hg
view tests/test-mq-missingfiles.t @ 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 | c70bdd222dcd |
children | fe3303436b79 |
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Issue835: qpush fails immediately when patching a missing file, but remaining added files are still created empty which will trick a future qrefresh. $ cat > writelines.py <<EOF > import sys > if sys.version_info[0] >= 3: > encode = lambda x: x.encode('utf-8').decode('unicode_escape').encode('utf-8') > else: > encode = lambda x: x.decode('string_escape') > path = sys.argv[1] > args = sys.argv[2:] > assert (len(args) % 2) == 0 > > f = open(path, 'wb') > for i in range(len(args) // 2): > count, s = args[2 * i:2 * i + 2] > count = int(count) > s = encode(s) > f.write(s * count) > f.close() > EOF $ echo "[extensions]" >> $HGRCPATH $ echo "mq=" >> $HGRCPATH $ hg init normal $ cd normal $ "$PYTHON" ../writelines.py b 10 'a\n' $ hg ci -Am addb adding b $ echo a > a $ "$PYTHON" ../writelines.py b 2 'b\n' 10 'a\n' 2 'c\n' $ echo c > c $ hg add a c $ hg qnew -f changeb $ hg qpop popping changeb patch queue now empty $ hg rm b $ hg ci -Am rmb Push patch with missing target: $ hg qpush applying changeb unable to find 'b' for patching (use '--prefix' to apply patch relative to the current directory) 2 out of 2 hunks FAILED -- saving rejects to file b.rej patch failed, unable to continue (try -v) patch failed, rejects left in working directory errors during apply, please fix and qrefresh changeb [2] Display added files: $ cat a a $ cat c c Display rejections: $ cat b.rej --- b +++ b @@ -1,3 +1,5 @@ +b +b a a a @@ -8,3 +10,5 @@ a a a +c +c Test missing renamed file $ hg qpop popping changeb patch queue now empty $ hg up -qC 0 $ echo a > a $ hg mv b bb $ "$PYTHON" ../writelines.py bb 2 'b\n' 10 'a\n' 2 'c\n' $ echo c > c $ hg add a c $ hg qnew changebb $ hg qpop popping changebb patch queue now empty $ hg up -qC 1 $ hg qpush applying changebb patching file bb Hunk #1 FAILED at 0 Hunk #2 FAILED at 7 2 out of 2 hunks FAILED -- saving rejects to file bb.rej b not tracked! patch failed, unable to continue (try -v) patch failed, rejects left in working directory errors during apply, please fix and qrefresh changebb [2] $ cat a a $ cat c c $ cat bb.rej --- bb +++ bb @@ -1,3 +1,5 @@ +b +b a a a @@ -8,3 +10,5 @@ a a a +c +c $ cd .. $ echo "[diff]" >> $HGRCPATH $ echo "git=1" >> $HGRCPATH $ hg init git $ cd git $ "$PYTHON" ../writelines.py b 1 '\x00' $ hg ci -Am addb adding b $ echo a > a $ "$PYTHON" ../writelines.py b 1 '\x01' 1 '\x00' $ echo c > c $ hg add a c $ hg qnew -f changeb $ hg qpop popping changeb patch queue now empty $ hg rm b $ hg ci -Am rmb Push git patch with missing target: $ hg qpush applying changeb unable to find 'b' for patching (use '--prefix' to apply patch relative to the current directory) 1 out of 1 hunks FAILED -- saving rejects to file b.rej patch failed, unable to continue (try -v) patch failed, rejects left in working directory errors during apply, please fix and qrefresh changeb [2] $ hg st ? b.rej Display added files: $ cat a a $ cat c c Display rejections: $ cat b.rej --- b +++ b GIT binary patch literal 2 Jc${No0000400IC2 $ cd .. Test push creating directory during git copy or rename: $ hg init missingdir $ cd missingdir $ echo a > a $ hg ci -Am adda adding a $ mkdir d $ hg copy a d/a2 $ hg mv a d/a $ hg qnew -g -f patch $ hg qpop popping patch patch queue now empty $ hg qpush applying patch now at: patch $ cd ..