elmPackages.elm: fails to connect to the elm package repository

[Pacrilege]

Nixpkgs version

• Stable (25.05)

Describe the bug

elm install and other commands accessing https://package.elm-lang.org/all-packages to fetch elm packages fail with the error InternalException (HandshakeFailed (Error_Protocol "peer does not support Extended Main Secret" HandshakeFailure)).

This is likely because the haskell tls library on versions >= 2.0.0 requires Extended Main Secret but https://package.elm-lang.org/all-packages does not support it. A possible fix would be to pin an earlier version of the haskell tls library as a dependency for elm.

Steps to reproduce

1. Install elmPackages.elm
2. run elm init in a directory you don't care about
3. run elm install BrianHicks/elm-csv (though any string matching .+/.+ should do as an argument)

If that doesn't fail with the above error, I have misdiagnosed the issue and this bug report is moot

Expected behaviour

elm install BrianHicks/elm-csv adds BrianHicks/elm-csv to the elm.json file with the current version of the package

Screenshots

No response

Relevant log output

~/projects/habitable-planets via 🌳 v0.19.1 via ❄️  impure (shell) ❯ elm install BrianHicks/elm-csv
-- PROBLEM LOADING PACKAGE LIST ------------------------------------------------

I need the list of published packages to figure out how to install things, so I
tried to fetch:

    https://package.elm-lang.org/all-packages

But my HTTP library is giving me the following error message:

    InternalException (HandshakeFailed (Error_Protocol "peer does not support Extended Main Secret" HandshakeFailure))

Are you somewhere with a slow internet connection? Or no internet? Does the link
I am trying to fetch work in your browser? Maybe the site is down? Does your
internet connection have a firewall that blocks certain domains? It is usually
something like that!

Additional context

ping package.elm-lang.org goes through, as does curl https://package.elm-lang.org/all-packages, so it probably is not something like that.

System metadata

• system: "x86_64-linux"
• host os: Linux 6.12.30, NixOS, 25.05 (Warbler), 25.05.20250525.7c43f08
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.28.3
• channels(root): "nixos-24.05"
• nixpkgs: /nix/store/vj980b72z6zb0yg6v0a7nzc9rcww3jmn-source

Notify maintainers

@domenkozar @turboMaCk

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[domenkozar]

Needs elm/compiler#2325

[turboMaCk]

I think it's unlikely this will be accepted upstream any time soon (from experience). But we can easily add patch on our side.