purescript-lua · Unisay · Jun 23, 2026 · Jun 23, 2026
diff --git a/CLAUDE.md b/CLAUDE.md
@@ -12,14 +12,20 @@ The project uses **Nix with flakes** for reproducible builds and **Cabal** for H
 
 ### Toolchain
 
-Versions are pinned by the flake (`compiler-nix-name` and `easy-ps.purs-*`
-in `flake.nix`); update them there, not locally:
+Versions are pinned by the flake (`compiler-nix-name` and the
+`purs-bin.*` / `spago-bin.*` attrs in `flake.nix`); update them there, not
+locally:
 
 - **GHC**: 9.8.x (haskell.nix `ghc98`)
-- **PureScript**: `purs` 0.15.16 (from easy-purescript-nix; note that attr
-  names may carry an upstream release suffix, e.g. `purs-0_15_16-0`)
+- **PureScript**: `purs` 0.15.16, from [purescript-overlay] pinned as
+  `purs-bin.purs-0_15_16` (explicit pin so `nix flake update` never silently
+  bumps the compiler and churns goldens)
 - **Spago**: 0.21.x — the *legacy* Haskell spago driven by `spago.dhall` /
-  `packages.dhall` (not the newer `spago.yaml`-based one)
+  `packages.dhall` (not the newer `spago.yaml`-based one), pinned as
+  `spago-bin.spago-0_21_0`. NB: the overlay's plain `spago` attr now resolves
+  to the new PureScript spago (1.x), hence the explicit legacy pin.
+
+[purescript-overlay]: https://github.com/thomashoneyman/purescript-overlay
 
 ### Development Environment
 
@@ -312,8 +318,10 @@ often enough; add more when the bug spans several code paths).
 ## Updating Dependencies
 
 1. `nix flake update` — refreshes haskell.nix (and with it the Hackage
-   index pin), nixpkgs, and easy-purescript-nix. To bump GHC or `purs`,
-   edit `compiler-nix-name` / `easy-ps.purs-*` in `flake.nix`.
+   index pin), nixpkgs, and purescript-overlay. To bump GHC, `purs`, or
+   spago, edit `compiler-nix-name` / `purs-bin.*` / `spago-bin.*` in
+   `flake.nix` (the toolchain attrs are explicitly version-pinned, so a flake
+   update alone never changes them).
 2. PureScript package sets live in `test/ps/packages.dhall` as
    `upstream-ps // upstream-lua`. The right operand wins: `upstream-lua`
    (releases of `purescript-lua/purescript-lua-package-sets`) overrides core

diff --git a/flake.lock b/flake.lock
diff --git a/flake.nix b/flake.nix
@@ -3,7 +3,8 @@
     haskellNix.url = "github:input-output-hk/haskell.nix";
     nixpkgs.follows = "haskellNix/nixpkgs-unstable";
     flake-utils.url = "github:numtide/flake-utils";
-    easy-purescript-nix.url = "github:justinwoo/easy-purescript-nix";
+    purescript-overlay.url = "github:thomashoneyman/purescript-overlay";
+    purescript-overlay.inputs.nixpkgs.follows = "nixpkgs";
     treefmt-nix.url = "github:numtide/treefmt-nix";
     treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";
   };
@@ -13,7 +14,7 @@
       nixpkgs,
       flake-utils,
       haskellNix,
-      easy-purescript-nix,
+      purescript-overlay,
       treefmt-nix,
     }:
     let
@@ -22,13 +23,13 @@
     flake-utils.lib.eachSystem supportedSystems (
       system:
       let
-        easy-ps = easy-purescript-nix.packages.${system};
         pkgs = import nixpkgs {
           inherit system overlays;
           inherit (haskellNix) config;
         };
         overlays = [
           haskellNix.overlay
+          purescript-overlay.overlays.default
           (final: prev: {
             psluaProject = final.haskell-nix.project' {
               src = ./.;
@@ -58,8 +59,8 @@
                 };
                 buildInputs = with pkgs; [
                   cachix
-                  easy-ps.purs-0_15_16-0
-                  easy-ps.spago
+                  purs-bin.purs-0_15_16
+                  spago-bin.spago-0_21_0
                   lua51Packages.lua
                   lua51Packages.luacheck
                   nil