Ruby 2.6.3 devenv

.envrc

#!/usr/bin/env bash

export DIRENV_WARN_TIMEOUT=20s
export NIXPKGS_ALLOW_INSECURE=1


eval "$(devenv direnvrc)"

# `use devenv` supports the same options as the `devenv shell` command.
#
# To silence all output, use `--quiet`.
#
# Example usage: use devenv --quiet --impure --option services.postgres.enable:bool true
use devenv --impure

devenv.nix

{ pkgs, lib, config, inputs, ... }:

{
  # https://devenv.sh/basics/
  env.GREET = "devenv";

  # https://devenv.sh/packages/
  packages = with pkgs;  [
    git
    libyaml
  ];

  env.NIX_CFLAGS_COMPILE = "-Wno-error=incompatible-pointer-types";

  languages.ruby = {
    enable = true;
    version = "2.6.3";
    bundler.enable = true;
    # listen_addresses = "localhost";
  };

  # https://devenv.sh/basics/
  enterShell = ''
    ruby --version
  '';
}

devenv.yaml

inputs:
  nixpkgs:
    url: github:cachix/devenv-nixpkgs/rolling
  nixpkgs-ruby:
    url: github:bobvanderlinden/nixpkgs-ruby
    inputs:
      nixpkgs:
        follows: nixpkgs

# If you're willing to use a package that's vulnerable
permittedInsecurePackages:
  - "openssl-1.1.1w"

Error log

error: Cannot build '/nix/store/c4bg3kdahn31kxs2q3972w8wvh48xa0y-ruby-2.6.3.drv'.
       Reason: builder failed with exit code 2.
       Output paths:
         /nix/store/ggyxs901qq5fa8i2750snlb15gkpb1cf-ruby-2.6.3
       Last 25 log lines:
       > cc1: note: unrecognized command-line option '-Wno-constant-logical-operand' may have been intended to silence earlier diagnostics
       > At top level:
       > cc1: note: unrecognized command-line option '-Wno-self-assign' may have been intended to silence earlier diagnostics
       > cc1: note: unrecognized command-line option '-Wno-parentheses-equality' may have been intended to silence earlier diagnostics
       > cc1: note: unrecognized command-line option '-Wno-constant-logical-operand' may have been intended to silence earlier diagnostics
       > building rb_mjit_header.h
       > linking miniruby
       > rb_mjit_header.h updated
       > generating encdb.h
       > building .ext/include/x86_64-linux/rb_mjit_min_header-2.6.3.h
       > ./miniruby -I./lib -I. -I.ext/common  ./tool/transform_mjit_header.rb "gcc " rb_mjit_header.h .ext/include/x86_64-linux/rb_mjit_min_header-2.6.3.h
       > encdb.h updated
       > error in initial header file:
       > In file included from /build/20260208-15334-17xmzqv.c:1:
       > /build/20260208-15334-12g14mu.h: In function 'vm_cref_dup':
       > /build/20260208-15334-12g14mu.h:9762:30: error: passing argument 2 of 'rb_hash_foreach' from incompatible pointer type [-Wincompatible-pointer-types]
       >  9762 |         rb_hash_foreach(ref, ref_delete_symkey, ((VALUE)RUBY_Qnil));
       >       |                              ^~~~~~~~~~~~~~~~~
       >       |                              |
       >       |                              int (*)(VALUE,  VALUE,  VALUE) {aka int (*)(long unsigned int,  long unsigned int,  long unsigned int)}
       > compilation terminated due to -Wfatal-errors.
       > make: *** [uncommon.mk:233: .ext/include/x86_64-linux/rb_mjit_min_header-2.6.3.h] Error 1
       > make: *** Waiting for unfinished jobs....
       > ./tool/ifchange "--timestamp=.rbconfig.time" rbconfig.rb rbconfig.tmp
       > rbconfig.rb updated