Try Julia repl does not load reliably

[DhairyaLGandhi]

https://julialang.org/learning/tryjulia/ has a fairly old (at this time!) version of Julia (1.3.1). Can that be updated?

[logankilpatrick]

I have had a PR open for this for months. https://Repl.it went into performance/stability mode and stopped merging PR's for things like language updates for the time being.

[logankilpatrick]

See here: replit/polygott#89

[logankilpatrick]

New PR: replit/polygott#222

Julia 1.4.3 should be available soon and 1.5.3 shortly thereafter.

[ViralBShah]

Should we remove reply.it?

[DhairyaLGandhi]

I would think so. Or at least link to places like a live Pluto app on juliahub or perhaps nextjournal?

[DilumAluthge]

I would prefer that instead of removing repl.it, we get replit/polygott#222 merged, and then upgrade to 1.6.2.

[logankilpatrick]

Regarding updating Julia, we are trying to converge with Nix's channel system. They have a stable Nix release every 6 months which can still be updated but all new updates must be backwards compatible. So if Julia has a new version that is backwards compatible, it can be updated in the latest stable Nix channel (If I understand correctly). Our Nix cache currently supports Nix stable 21.11 and unstable and those caches will be updated periodically (ideally weekly). The best way to get Julia updated is to get it backported on the latest stable release of Nix (assuming backwards compatibility).

If there are backwards incompatible changes made to Julia, it can be updated in the unstable Nix branch, but ideally our base templates always use a stable Nix channel to mitigate repls breaking. We will support all future Nix stable channels, which means you may have to wait up to 6 months to update the base Julia template if there are breaking changes.

@DilumAluthge from the folks at Replit

[DilumAluthge]

I know very little about Nix, so we may need to bring in some other people to help with this.

Are they saying that they will only use Julia if there is a Nix package for Julia?

How does Nix currently distribute Julia? Do they distribute the official binaries from the Julia website? Or do they build it themselves? If Nix builds Julia themselves, and if Repl.it only uses the Nix Julia, I'd be reluctant to keep Repl.it on the Julia website.

[logankilpatrick]

I just pinged in the nix channel on Slack to see if we can get some more nix experts.

[ViralBShah]

Can't we just provide a shell script to users to download and install Julia on login? Maybe just juliaup. Seems like a much easier solution.

Building something special here means either is committing to do it forever or having older versions when we can't keep up.

Maybe replit staff can package Julia as part of their distribution? Our views here should be the same as those for packaging for other Linux distros.

[rikhuijzer]

How does Nix currently distribute Julia? Do they distribute the official binaries from the Julia website? Or do they build it themselves?

See https://github.com/NixOS/nixpkgs/tree/master/pkgs/development/compilers/julia: 1.6 and 1.7 are based on the official binaries. Note that only 1.6 is on the stable channel (https://github.com/NixOS/nixpkgs/tree/21.11/pkgs/development/compilers/julia).

Maybe replit staff can package Julia as part of their distribution?

They say that they don't want that, right? They use Nix because "This should make getting the latest version of Julia much, much easier." (replit/polygott#222 (comment)). In theory, I agree. But since they stick to "We will support all future Nix stable channels, which means you may have to wait up to 6 months to update the base Julia template if there are breaking changes." they contradict themselves. The system is so "easy" that it is always about 6 months behind.

I authored and maintain the non-source Nix packages: julia-lts-bin and julia-stable-bin (currently pointing to julia_17-bin and julia_16-bin) on Nixpkgs master (which then feeds into the unstable channel). If Repl.it wants to follow stable for everything, they are more than welcome to backport non-breaking changes to stable. It is not hard work, but takes cherry picking commits, submitting a PR, and ensuring that someone with commit rights is convinced that you are indeed not breaking stable and that the update is warranted. Alternatively, it is not like it is difficult to mix channels with Nix/NixOS (I have my base system on stable, but lift in specific packages like Julia from unstable and of course have a handful of packages that I maintain privately as I do not want to commit to maintaining everything I use upstream). This is where Nix absolutely shines, so I am not sure why Repl.it would not go down this route for a language that moves significantly faster than say Python.

It literally is as simple as adding this to your configuration:

config.packageOverrides = pkgs: {
    # Run when installing a new system:
    #
    #   nix-channel --add https://nixos.org/channels/nixos-unstable nixos-unstable
    #   nix-channel --update
    unstable = import <nixos-unstable> { config = config.nixpkgs.config; };
}

Then you can just replace julia-bin-stable with unstable.julia-bin-stable wherever you mention it and you will follow unstable for that package only and the rest of your system will still be on stable. I think this only applies for your global configuration though, if you want it to seep all the way down into your shell.nix files and the likes you probably need to refer to the manual (do tell me if do as I would me curious exactly how this interoperates).

[adkabo]

@logankilpatrick quoted

So if Julia has a new version that is backwards compatible, it can be updated in the latest stable Nix channel (If I understand correctly).

On Nix stable channels, normally only package bugfixes and security fixes are applied between semiannual major releases -- upgrading from 1.6 to 1.7 would likely be too much. If Replit also provides an option to access Nixpkgs unstable, new versions would be available on a rolling basis.

[ViralBShah]

When I go here, nothing loads - I just get an empty page: https://julialang.org/learning/tryjulia/

@logankilpatrick is this supposed to give us a working Julia repl? I feel it is best to take it down if it is not reliable. I haven't been able to get anything but a grey page for a long time.

[logankilpatrick]

If you use chrome incognito, then it stops working, else, it works as expected with Julia 1.6.3 right now.