8 ms·

You can because all allocations are tracked and explicit

by slekker 2mo ago

onlyrealcuzzo 2mo ago
Allocations are less of a problem than aliases. Without affine/linear ownership - solving the aliasing problem is the Halting Problem. Rust didn't invent Affine Ownership just to make Rust hard. It did it because it's one of the only ways to have memory safety without a GC.
- dnautics 2mo ago
  1. rust didnt invent affine ownership. 2. It's possible to bolt on to other languages (see ada). zig in particular is easy (disclaimer: i think, i haven't implemented it yet)
  - onlyrealcuzzo 2mo ago
    > zig in particular is easy (disclaimer: i think, i haven't implemented it yet) I guess it's "easy" compared to other languages - but if you think it's "easy", we have different definitions of "easy". You could implement it, but it would look like efforts in Rust to get SPARK-like safety, and SPARK itself. It will essentially be a different language. You will not be able to work seamlessly with any regular Zig code. That may or may not be a problem if you're willing to assume you can just use it all unsafely and it works enough that things are fine. That's somewhat analogous to unsafe Rust. The difference with unsafe Rust is... That's a very small fraction of what you're using, not the vast majority of what you use. When you use a Rust crate - you generally do not expect that it could have infinite race conditions. It may have some unsafe code, but that should be the exception, not the norm. By all means, please build it. I'd consider using it [=
    - dnautics 2mo ago
      > You will not be able to work seamlessly with any regular Zig code. That may or may not be a problem if you're willing to assume you can just use it all unsafely and it works enough that things are fine. that may be true, but it seems "not". to date, all of the patterns in zig-clr nudge you towards idiomatic zig and not away from it. i run tests on not-my-code (an unaltered version of an existing zig project -- you can see it's vendored in the "vendored/validate"), and it passes. still working through forestmq. and I'm planning a mechanism to let you reach into a function and "oracle" its safety parameters, probably most useful when someone else has written code that you know is ok but you cant tell them "hey make this work to pass my linter" Also remember that zig compiles as a single compilation unit so even if you draw in zig dependencies, unless they are hidden behind a .so, zig-clr will analyze the dependency code too.
      - onlyrealcuzzo 2mo ago
        By all means - reach out when it's ready and I'll give it a test. I'm highly skeptical you can get it to work. If it was easy and optional and non-invasive and actually worked - the Zig team would almost certainly build it. But, even if it just mostly works - that would still be very useful if it's non invasive.
        dnautics 2mo ago
        > the Zig team would almost certainly build it 1. It's a small team. 2. The zig team is parsimonious about what they do and don't build. For example, they did not work on the language server, rather punting it to the community. 3. That you can do this with the zig compiler is a happy accident. The team was not designing towards this possibility, it's not really a part of the core zig ethos (and that's fine). 4. You certainly cannot do things exactly the way that rust does it without changing the language; because the rust conversation has sucked all of the air out of the discourse around safety, you really do have to make a paradigm shift away from "tagged ownership" to "data dependency tracking with ownership agnosticism" to do it with zig.
        onlyrealcuzzo 2mo ago
        You either do it with Linear Types, Affine Types, or you have holes... Or you've invented a novel new system and should be publishing white papers immediately. You can do virtually everything Zig comptime does in Brute Force in C++23. If this was possible - completely, it would already be done for C++. You need to point out exactly what you can do in Zig that you can't in C that somehow magically makes this completely possible and bulletproof in Zig - otherwise, you have a "concept of a plan". The reason Rust sucked the air out of the room is that people are much more interested in systems without holes than systems that mostly work, or partially solve small parts of the problem and/or rely on the developer getting it right. I hope you're right, but hope is a bad strategy.
        dnautics 2mo ago
        its refinement types which are a "superset of affine types" iiuc (you can construct a refinement type system that can represent affine types, plus more). there is nothing special about zig that makes it fundamentally possible in zig and impossible in C. the difference is that compiler architecture, some language decisions, well-designed stdlib, not having to contend with past decisions of a committee that overweighted backwards compatibility, take it from "jesus christ this is too much of a pain in the ass to bother" to "oh theres actually a path forward for one person and an llm". As a concrete example. In C there is no "anointed allocator", sure, most people use malloc/free, but a broadly useful analyzer needs to be able to contend with any of a billion different patterns, and "oops I forgot jemalloc's mallocx" is not really okay (plus you gotta deal with weird things like errno, etc, and maybe some program uses jemalloc's free in some places and stdlib free in other places, how do you track that). In zig, sure, you could build a function that allocates off the stdlib path, but it's not unreasonable to "ban" that and force people to use the stdlib interface, and most dependencies will be compliant. Hopefully you can see how this "jesus christ i don't want to deal with all that" vs "a clean path forward".
gpm 2mo ago
That's not sufficient - consider the following pseudocode x = malloc(); if (opaque_cond()) free(x); if (other_opaque_cond()) use(x); Conditions can be opaque and non-analyzable due to rices theorem - in any turing complete language. This code is correct (or at least not memory unsound) if opaque_cond and other_opaque_cond are never both true. Otherwise it isn't. And functionally compiler analyses of whether conditions hold have to be trivial because using some form of theorem prover to decide of code is correct or not leads to code that is brittle against compiler version changes, and slow compile times. Thus opaque_cond could be as simple as `len == 0` and `other_opaque_cond` could be `len > 0` and it's unlikely you'd want the compiler to realize those are mutually exclusive (at the stage where it accepts programs, obviously during optimization it is very likely to take advantage of this). Rust solves this by simply rejecting the pattern. Very roughly forcing you to write if opaque_cond() { free(x) } else if other_opaque_cond() { use_x } (or something else where the program structure and not just the logic in the conditions guarantees correctness). Zig simply allows it and leaves it up to the programmer not to make a mistake. And as onlyrealcuzzo suggests aliases are where this type of analysis (accepting enough programs to be useful but still imposing enough structure you can prove correctness) is really tricky.
- dnautics 2mo ago
  so yes it is possible to detect those patterns and ban them as unsafe, and have a"safety checked alternative. clr does this currently: https://github.com/ityonemo/clr#safety-oriented-architecture https://github.com/ityonemo/clr#safety-oriented-architecture
  - dnautics 2mo ago
    i dont understand the downvotes here. the point of any safety checker is to flag and ban potentially unsafe code, and force the author to rewrite with existing language patterns that guarantee the desired safety parameters. in this case, zig has a first class nullable syntax that the checker can use ti guarantee correctness for, so a checker can deterministically sidestep this turing completeness issue, by squeezing indeterminate code into the knowably safer language idiom.
  - 2mo ago
deleted 2mo ago
[deleted]

You can because all allocations are tracked and explicit

by slekker 2mo ago

You can because all allocations are tracked and explicit

Allocations are less of a problem than aliases. Without affine/linear ownership - solving the aliasing problem is the Halting Problem. Rust didn't invent Affine Ownership just to make Rust hard. It did it because it's one of the only ways to have memory safety without a GC.

dnautics 2mo ago
1. rust didnt invent affine ownership. 2. It's possible to bolt on to other languages (see ada). zig in particular is easy (disclaimer: i think, i haven't implemented it yet)
- onlyrealcuzzo 2mo ago
  > zig in particular is easy (disclaimer: i think, i haven't implemented it yet) I guess it's "easy" compared to other languages - but if you think it's "easy", we have different definitions of "easy". You could implement it, but it would look like efforts in Rust to get SPARK-like safety, and SPARK itself. It will essentially be a different language. You will not be able to work seamlessly with any regular Zig code. That may or may not be a problem if you're willing to assume you can just use it all unsafely and it works enough that things are fine. That's somewhat analogous to unsafe Rust. The difference with unsafe Rust is... That's a very small fraction of what you're using, not the vast majority of what you use. When you use a Rust crate - you generally do not expect that it could have infinite race conditions. It may have some unsafe code, but that should be the exception, not the norm. By all means, please build it. I'd consider using it [=
  - dnautics 2mo ago
    > You will not be able to work seamlessly with any regular Zig code. That may or may not be a problem if you're willing to assume you can just use it all unsafely and it works enough that things are fine. that may be true, but it seems "not". to date, all of the patterns in zig-clr nudge you towards idiomatic zig and not away from it. i run tests on not-my-code (an unaltered version of an existing zig project -- you can see it's vendored in the "vendored/validate"), and it passes. still working through forestmq. and I'm planning a mechanism to let you reach into a function and "oracle" its safety parameters, probably most useful when someone else has written code that you know is ok but you cant tell them "hey make this work to pass my linter" Also remember that zig compiles as a single compilation unit so even if you draw in zig dependencies, unless they are hidden behind a .so, zig-clr will analyze the dependency code too.
    - onlyrealcuzzo 2mo ago
      By all means - reach out when it's ready and I'll give it a test. I'm highly skeptical you can get it to work. If it was easy and optional and non-invasive and actually worked - the Zig team would almost certainly build it. But, even if it just mostly works - that would still be very useful if it's non invasive.
      - dnautics 2mo ago
        > the Zig team would almost certainly build it 1. It's a small team. 2. The zig team is parsimonious about what they do and don't build. For example, they did not work on the language server, rather punting it to the community. 3. That you can do this with the zig compiler is a happy accident. The team was not designing towards this possibility, it's not really a part of the core zig ethos (and that's fine). 4. You certainly cannot do things exactly the way that rust does it without changing the language; because the rust conversation has sucked all of the air out of the discourse around safety, you really do have to make a paradigm shift away from "tagged ownership" to "data dependency tracking with ownership agnosticism" to do it with zig.
        onlyrealcuzzo 2mo ago
        You either do it with Linear Types, Affine Types, or you have holes... Or you've invented a novel new system and should be publishing white papers immediately. You can do virtually everything Zig comptime does in Brute Force in C++23. If this was possible - completely, it would already be done for C++. You need to point out exactly what you can do in Zig that you can't in C that somehow magically makes this completely possible and bulletproof in Zig - otherwise, you have a "concept of a plan". The reason Rust sucked the air out of the room is that people are much more interested in systems without holes than systems that mostly work, or partially solve small parts of the problem and/or rely on the developer getting it right. I hope you're right, but hope is a bad strategy.
        dnautics 2mo ago
        its refinement types which are a "superset of affine types" iiuc (you can construct a refinement type system that can represent affine types, plus more). there is nothing special about zig that makes it fundamentally possible in zig and impossible in C. the difference is that compiler architecture, some language decisions, well-designed stdlib, not having to contend with past decisions of a committee that overweighted backwards compatibility, take it from "jesus christ this is too much of a pain in the ass to bother" to "oh theres actually a path forward for one person and an llm". As a concrete example. In C there is no "anointed allocator", sure, most people use malloc/free, but a broadly useful analyzer needs to be able to contend with any of a billion different patterns, and "oops I forgot jemalloc's mallocx" is not really okay (plus you gotta deal with weird things like errno, etc, and maybe some program uses jemalloc's free in some places and stdlib free in other places, how do you track that). In zig, sure, you could build a function that allocates off the stdlib path, but it's not unreasonable to "ban" that and force people to use the stdlib interface, and most dependencies will be compliant. Hopefully you can see how this "jesus christ i don't want to deal with all that" vs "a clean path forward".

gpm 2mo ago

That's not sufficient - consider the following pseudocode x = malloc(); if (opaque_cond()) free(x); if (other_opaque_cond()) use(x); Conditions can be opaque and non-analyzable due to rices theorem - in any turing complete language. This code is correct (or at least not memory unsound) if opaque_cond and other_opaque_cond are never both true. Otherwise it isn't. And functionally compiler analyses of whether conditions hold have to be trivial because using some form of theorem prover to decide of code is correct or not leads to code that is brittle against compiler version changes, and slow compile times. Thus opaque_cond could be as simple as `len == 0` and `other_opaque_cond` could be `len > 0` and it's unlikely you'd want the compiler to realize those are mutually exclusive (at the stage where it accepts programs, obviously during optimization it is very likely to take advantage of this). Rust solves this by simply rejecting the pattern. Very roughly forcing you to write if opaque_cond() { free(x) } else if other_opaque_cond() { use_x } (or something else where the program structure and not just the logic in the conditions guarantees correctness). Zig simply allows it and leaves it up to the programmer not to make a mistake. And as onlyrealcuzzo suggests aliases are where this type of analysis (accepting enough programs to be useful but still imposing enough structure you can prove correctness) is really tricky.

dnautics 2mo ago
so yes it is possible to detect those patterns and ban them as unsafe, and have a"safety checked alternative. clr does this currently: https://github.com/ityonemo/clr#safety-oriented-architecture https://github.com/ityonemo/clr#safety-oriented-architecture
- dnautics 2mo ago
  i dont understand the downvotes here. the point of any safety checker is to flag and ban potentially unsafe code, and force the author to rewrite with existing language patterns that guarantee the desired safety parameters. in this case, zig has a first class nullable syntax that the checker can use ti guarantee correctness for, so a checker can deterministically sidestep this turing completeness issue, by squeezing indeterminate code into the knowably safer language idiom.
- 2mo ago

deleted 2mo ago

[deleted]