47 lines
1.5 KiB
Markdown
47 lines
1.5 KiB
Markdown
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---
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date: 2025-06-25
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title: Nix and older versions of PHP
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permalink: /daily/2025/06/25/nix-and-older-versions-php
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---
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Yesterday, I wrote about [using Nix to create shells for different versions of PHP][1].
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The current stable version of Nix has PHP 8.4.8, 8.3.22, 8.2.28 and 8.1.32, but what if you need an older version?
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If it has been in nixpkgs previously, it can still be accessed.
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Nix allows you to create different channels to install different versions of the nixpkgs repository and access different sets of packages.
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With flakes, different versions of nixpkgs can be used as inputs to add multiple releases, such as [stable and unstable][0], or older releases or even a specific Git commit.
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For example, if I needed to use PHP 7.4 - which is not available in the current release - I could use this flake.nix file:
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```nix
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{
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inputs = {
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nixpkgs-php74.url = "github:nixos/nixpkgs/81b77fd3847a";
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};
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outputs = { nixpkgs-php74, ... }:
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let
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system = "x86_64-linux";
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pkgs = import nixpkgs-php74 { inherit system; };
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in {
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devShells.${system}.default = pkgs.mkShell {
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packages = [
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pkgs.php74
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];
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};
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};
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}
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```
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Pinning nixpkgs to that commit hash gives me access to `php74`, which I can access using `nix develop`.
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This approach works with any package in nixpkgs - not just PHP.
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Or, if it wasn't available in an older version of nixpkgs, I can write a custom derivation and add it myself.
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[0]: /daily/2025/05/25/why-i-prefer-rolling-linux-distribution
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[1]: /daily/2025/06/24/php-and-nix-shells
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