quick-protobuf VS rust-playground

[quick-protobuf]: https://github.com/tafia/quick-protobuf

I actually went through all projects listed in [1] because I remember this very quirk. It turns out that there are many such libraries that have two variants of encode/decode functions, where the second variant prepends a varint length. In my brief inspection there do exist a few libraries with only the second variant (e.g. Rust quick-protobuf), which is legitimately problematic [2].

But if the project in question was indeed protobuf.js (see loeg's comments), it clearly distinguishes encode/decode vs. encodeDelimited/decodeDelimited. So I believe the project should not be blamed, and the better question would be why so many people chose to add this exact helper. Well, because Google itself also had the same helper [3]! So at this point protobuf should just standardize this simple framing format (with an explicitly different name though), instead of claiming that protobuf has no obligation to define one.

[1] https://github.com/protocolbuffers/protobuf/blob/main/docs/t...

[2] https://github.com/tafia/quick-protobuf/issues/130

[3] https://protobuf.dev/reference/java/api-docs/com/google/prot...

[4] https://github.com/protocolbuffers/protobuf/blob/main/src/go...

If you have an object that's !Unpin, then Miri will not apply uniqueness rules to anything containing it [0], including boxes and &mut references. (In the example code, replacing the PhantomPinned with a () will make Miri complain again.) This is considered a temporary (if long-lived) measure to allow async executors to manipulate pinned futures without invalidating all their references and whatnot. Thus, it might be seen as undetected UB, in lieu of a permanent solution.

[0] https://play.rust-lang.org/?version=stable&mode=debug&editio...

That would be true if you used `Vec::clear` too, it doesn't allocate a new vector. My point was that you still end up running Drop implementations with RepeatedField, just not all at once. See https://play.rust-lang.org/?version=stable&mode=debug&editio...

That's a valid Unix path, but rust's quoting does nothing to stop it: https://play.rust-lang.org/?version=stable&mode=debug&editio...

Self-referential structs work fine in Rust and always have.

https://play.rust-lang.org/?version=stable&mode=debug&editio...

The compiler will correctly prevent you from moving the value.

The other way to have a struct that starts out as non-self-referential and then becomes self-referential can be achieved with `unsafe` and `Pin::new_unchecked`, which is how `async {}` is handled.

In rust as currently stands: https://play.rust-lang.org/?version=stable&mode=debug&editio...

On the other hand, both this wrapper and yours are counterproductive if the element size is dynamic (e.g. perhaps you're dealing with some nonsense like:)

    struct ITableColumn {

Overflow checks turn into two's compliments' wrapping, but that's only considered acceptable because bounds checks are not turned off.

https://play.rust-lang.org/?version=stable&mode=release&edit...

I have no idea what you're talking about, but it sounds unnecessarily complicated and why I don't use Rust for any serious work.

This demonstrates the ABA problem in safe Rust: https://play.rust-lang.org/?version=stable&mode=debug&editio...

Substitute the sleep with a combination of doing computation/work and the OS thread scheduler, and you can see how the bug surfaces.

You can also try Rust online using the Rust playground: https://play.rust-lang.org/

(Click ... beside build to get assembly) https://play.rust-lang.org/?version=stable&mode=release&edit...

Unfortunately the go playground doesn't seem to support emitting assembly?