Hi, author of this devlog here! Not to dismiss concerns about breaking language changes, but there seems to be a bit of a misconception here that this compiler change was highly breaking and will require significant effort from Zig users to update for. Perhaps I unintentionally gave that impression in the devlog or the PR writeup, apologies if so---but it's not the case! Although there were breaking changes in this patch, they were quite minor: most users are unlikely to hit them, and if they do then they're straightforward to deal with.

For a concrete example, while testing this branch, I tried building ZLS (https://github.com/zigtools/zls/). To do that, the only change I had to make was changing `.{}` to `.empty` in a couple of its dependencies (i.e. not even in ZLS itself!). This was needed because I removed some default values from `std.ArrayList` (so the change was in standard library code rather than the language). Those default values had actually already been deprecated (with intent to remove) for around a year, so this wasn't exactly a new change either.

As another example, Andrew has updated Awebo (https://codeberg.org/awebo-chat/awebo), a text and voice chat application, to the new version of Zig. Across Awebo's entire dependency tree (which includes various packages for graphics, audio, and probably some other stuff), the full set of necessary changes was:

* Same as above, change `.{}` to `.empty` in a few places, due to removal of deprecated defaults

* Add one extra `comptime` annotation to logic which was constructing an array at comptime

* Append `orelse @alignOf(T)` onto an expression to deal with a newly-possible `null` case

These are all trivial fixes which Zig developers would be able to do pretty much on autopilot upon seeing the compile errors.

So, while there were a handful of small breaking changes, they don't seem to me like a particularly big deal (for a language where some level of breakage is still allowed). The main thing this PR achieved was instead a combination of bugfixes, and enhancements to existing features (particularly incremental compilation).

I would really like to hear from people using Zig in production/semi-serious applications; where software stability is important.

How's your experience with the constantly changing language? How're your update/rewrite cycles looking like? Are there cases where packages you may use fall behind the language?

I know Bun's using zig to a degree of success, was wondering how the rest were doing.

I am impressed by the achievements of the Zig team. I use the ghostty terminal emulator regularly -- it is built in Zig and it is super stable. It is a fantastic piece of software.

This makes me feel that the underlying technology behind Zig is solid.

But I prefer Rust over Zig. The main difference is Rust chooses a "closed world" model while Zig chooses an "open world" model: in Rust, you must explicitly implement a trait while in Zig as long as the shape fits, or the `.` on a structure member exists (for whichever type you pass in), it will work (I don't use Zig so pardon hand wavy description).

This gives Zig very powerful meta programming abilities but is a pain because you don't know what kind of type "shapes" will be used in a particular piece of code. Zig is similar to C++ templates in some respects.

This has a ripple effect everywhere. Rust generated documentation is very rich and explicit about what functions a structure supports (as each trait is explicitly enrolled and implemented). In Zig the dynamic nature of the code becomes a problem with autocomplete, documentation, LSP support, ...

The kernel32 -> Ntdll changes are the most interesting thing to me here. A lot of the rationale is applicable also to the linux userspace APIs, especially errors in return at the kernel-userspace boundary vs GetLastError/errno in kernel32/libc. Of course on linux the "problem" is that libc and the kernel API are intimately intertwined and the former mandates using errno. I wonder how the pattern made its way into windows as well. That environment has never seemed to me to promote using libc.

I just have to add another reflection:

One thing that tends to be overlooked when discussing changes is the ecosystem effect of frequent changes.

A language that breaks frequently doesn't just impose upgrade work on apps, but also discourages the creation of long-lived libraries and tools. Anything that sits between the language and the user (linters, bindings, frameworks, teaching material, tutorials etc) has to to some degree "chase the language"

This means that the ecosystem will skew toward very actively maintained libraries and away from "write once then leave it alone" libs. And this the trade-off is reasonable during early language design, but it's worth acknowledging that it has real consequences for ecosystem growth.

One should note that other newer languages have put significant effort into minimizing this churn, precisely to allow the latter type of ecosystem to also form. So it's kind of an experiment, and it will be interesting to see which approach ends up producing the larger ecosystem over time.

Instead of implementing a workaround for types as namespaces, wouldn't it better to explicitly add namespaces to the language?

> Many projects including Chromium, boringssl, Firefox, and Rust call SystemFunction036 from advapi32.dll because it worked on versions older than Windows 8.

That's not true. They use ProcessPrng since versions earlier than 10 are no longer supported (well, rust also has a windows 7 target but that couldn't use ProcessPrng anyway since it wasn't available). The issue they linked is from a decade ago. E.g. here's Chromium: https://github.com/chromium/chromium/blob/dc7016d1ef67e3e128...

> If [ProcessPrng] fails it returns NO_MEMORY in a BOOL (documented behavior is to never fail, and always return TRUE).

From Windows 10 onward ProcessPrng will never fail. There's a whitepaper that gives the justification for this (https://aka.ms/win10rng):

> We also have the property that a request for random bytes never fails. In the past our RNG functions could return an error code. We have observed that there are many callers that never check for the error code, even if they are generating cryptographic key material. This can lead to serious security vulnerabilities if an attacker manages to create a situation in which the RNG infrastructure returns an error. For that reason, the Win10 RNG infrastructure will never return an error code and always produce high-quality random bytes for every request...

> For each user-mode process, we have a (buffered) base PRNG maintained by BCryptPrimitives.dll. When this DLL loads it requests a random seed from kernel mode (where it is produced by the per-CPU states) and seeds the process base PRNG. If this were to fail, BCryptPrimitive.dll fails to load, which in most cases causes the process to terminate. This behavior ensures that we never have to return an error code from the RNG system.

Move 'ZIG'.

What makes zig special as a language? I have the impression that it has quite a large fan base here on HN but don't really hear any talks about it anywhere else.

It’s good to see that this is finally addressed. It’s been a well known broken part of the language semantics for years.

There are similar hidden quirks in the language that will need to be addressed at some point, such as integer promotion semantics.

To address the question about stability: the Zig community are already used to Zig breaking between 0.x versions. Unlike competitors such as Odin or my own C3, there is no expectation that Zig is trying to minimize upgrading problems.

This is a cultural thing, it would be no real problem to be clear about deprecations, but in the Zig community it’s simply not valued. In fact it’s a source of pride to be able to adapt as fast as possible to the new changes.

I like to talk about expectation management, and this is a great example of it.

In discussions, it is often falsely argued that ”Zig is not 1.0 so breaks are expected” in order to motivate the frequent breaks. However, there are degrees to how you handle breaks, and Zig is clearly in the ”we don’t care to reduce the work”-camp.

If someone is trying to get a more objective look at the Zig upgrade path, then it’s worth keeping in mind that the tradition in Zig is to offload all the work on the user.

The argument, which is frequently voiced, is that ”breaking things will make the language get better and so it’s good that there are language breaks”

It is certainly true that breaking changes are needed, but most people outside of the Zig community would expect it to be done with more care (deprecation paths etc)

Secondly, it should perhaps be a concern for Zig, now at 10 years old, to still produce solidly breaking code every half year.

10 years is the common point where languages go 1.0. However, the outlook for a Zig 1.0 is bleak from what I gather from Zig social forums: the most optimistic estimate I’ve heard is 2029 for 1.0.

This means that in the future, projects using Zig can still expect any libraries and applications to bitrot quickly if they are not constantly maintained.

Putting this in contrast with Odin (9 years old) which is essentially 1.0 already and has been stable for several years.

Maybe this also explains the difference in actual output. For example the number of games I know of written in Odin is somewhere between 5 to 10 times as many as Zig games. Now weighing in that Zig has maybe 5 or 10 times as many users, it means Odin users are somewhere between 20-100 times as likely to have written a playable game.

There are several explanations as to why this is: we could discuss whether the availability of SDL, Raylib etc is easier on Odin (then why is Zig less friendly?), maybe more Odin has better programmers (then why do better programmers choose Odin over Zig), maybe it’s just easier to write resource intensive applications with Odin than Zig (then what do we make of Zig’s claim of optimality?)

If we look past the excuses made for Zig (”it’s easy to fix breaks” ”it’s not 1.0”) and the hype (”Zig is much safer than C” ”Zig makes me so productive”) and compare with Odin in actual productivity, stability and compilation speed (neither C3 nor Odin requires 100s of GB of cache to compile in less than a second using LLVM) then Zig is not looking particularly good.

Even things like build.zig, often touted as a great thing, is making it really hard for a Zig beginner (”to build your first Hello World, first understand this build script in non-trivial Zig”). Then for IDEs, suddenly something like just reading the configuration of what is going to be used for building is hidden behind an opaque Zig script. These trade-offs are rarely talked about, as both criticism and hype is usually based on surface rather than depth.

Well, that’s long enough of a comment.

To round it off I’d like to end on a positive note: I find the Zig community nice and welcoming. So if you’re trying Zig out (and better do that, don’t let others’ opinions - including mine - prevent you from trying things out) do so.

If you want to evaluate Zig against competitors, I’d recommend comparing it to D, Odin, Jai and C3.

Congratulations to the dev, a 30,000 line PR for a language compiler (and a very much non-trivial compiler) is a feat to be proud of. But a change of this magnitude is a serious bit of development and gave me pause.

I understand both of the following:

1. Language development is a tricky subject, in general, but especially for those languages looking for wide adoption or hoping for ‘generational’ (program life span being measured in multiple decades) usage in infrastructure, etc.

2) Zig is a young-ish language, not at 1.0, and explicitly evolving as of the posting of TFA

With those points as caveats, I find the casualness of the following (from the codeburg post linked on the devlog) surprising:

‘’’This branch changes the semantics of "uninstantiable" types (things like noreturn, that is, types which contain no values). I wasn't originally planning to do this here, but matching the semantics of master was pretty difficult because the existing semantics don't make much sense.’’’

I don’t know Zig’s particular strategy and terminology for language and compiler development, but I would assume the usage of ‘branch’ here implies this is not a change fully/formally adopted by the language but more a fully implemented proposal. Even if it is just a proposal for change, the large scale of the rewrite and clear implication that the author expects it to be well received strikes me as uncommon confidence. Changing the semantics of a language with any production use is nearly definitionally MAJOR, to just blithely state your PR changes semantics and proceed with no deep discussion (which could have previously happened, IDK) or serious justification or statements concerning the limited effect of those changes is not something I have experienced watching the evolution (or de-evolution) of other less ‘serious’ languages.

Is this a “this dev” thing, a Zig thing, or am just out of touch with modern language (or even larger scale development) projects?

Also, not particularly important or really significant to the overall thrust of TFA, but the author uses the phrase “modern Zig”, which given Zig’s age and seeming rate of change currently struck me as a very funny turn of phrase.