Raphaël Gomès <rgomes@octobus.net> [Tue, 05 Apr 2022 10:55:28 +0200] rev 49001
rust-dirstate: panic if the DirstateMap counters go below 0
When modifying the API I hit some... interesting errors (trying to allocate
178GB of RAM, for example) because I failed to keep the counters correctly
updated.
This counter underflow is likely to happen when code is changed around
and can have up to eat-your-dirstate level of consequences, which is not nice.
The very small runtime cost of checking these counters should really not be an
issue and will help us uncover bugs when/if they do appear in the future.
Differential Revision: https://phab.mercurial-scm.org/D12430
Raphaël Gomès <rgomes@octobus.net> [Tue, 05 Apr 2022 10:55:28 +0200] rev 49000
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
Raphaël Gomès <rgomes@octobus.net> [Tue, 05 Apr 2022 10:55:27 +0200] rev 48999
rust: explain why the current `OwningDirstateMap` is unsound
See inline comments.
Differential Revision: https://phab.mercurial-scm.org/D12428
Valentin Gatien-Baron <vgatien-baron@janestreet.com> [Fri, 01 Apr 2022 12:46:58 -0400] rev 48998
dispatch: fix silly blackbox entries when hg is interrupted
When hg is interrupted, it creates ui.log like this:
1970/01/01 00:00:00 user @0000000000000000000000000000000000000000 (62488)> killed!
exited 255 after 1.78 seconds
This is due to a scoping problem: two different uses of the name "msg"
collide. So rename one of them.
Differential Revision: https://phab.mercurial-scm.org/D12427
Matt Harbison <matt_harbison@yahoo.com> [Wed, 30 Mar 2022 00:57:08 -0400] rev 48997
tests: stop excluding the pycompat module from pyflakes
I assume this was skipped because of all of the py2 stuff causing a lot of spew.
The "unused" imports are left in place in case any 3rd party stuff is using it.
I don't care about most of it, but TortoiseHg uses `io` and `queue`, so
minimally I'd like to keep those.
Differential Revision: https://phab.mercurial-scm.org/D12423
Matt Harbison <matt_harbison@yahoo.com> [Wed, 30 Mar 2022 00:44:55 -0400] rev 48996
tests: drop some py2 specific pyflake failures
Differential Revision: https://phab.mercurial-scm.org/D12422
Matt Harbison <matt_harbison@yahoo.com> [Tue, 29 Mar 2022 23:31:37 -0400] rev 48995
util: drop a duplicate import
This was already imported several lines above.
Differential Revision: https://phab.mercurial-scm.org/D12421
Matt Harbison <matt_harbison@yahoo.com> [Tue, 29 Mar 2022 23:34:18 -0400] rev 48994
pycompat: drop the pickle import
I suspect this is what df56e6bd37f6 meant to eliminate.
Differential Revision: https://phab.mercurial-scm.org/D12420
Matt Harbison <matt_harbison@yahoo.com> [Tue, 29 Mar 2022 22:22:36 -0400] rev 48993
util: restore the util.pickle symbol
This was accidently dropped in df56e6bd37f6, which started importing pickle
directly. That commit explicitly says it will retain it for compatibility with
external stuff though.
The unused import in pycompat isn't flagged because that module is skipped.
Just importing with a comment seemed cleaner than `import X as Y` and then
assigning to a `pickle` variable, just to avoid the pyflakes warning.
Differential Revision: https://phab.mercurial-scm.org/D12419
Raphaël Gomès <rgomes@octobus.net> [Tue, 29 Mar 2022 14:27:45 +0200] rev 48992
merge: stable into default