[nix] Add package for official golang binaries to the dev shell

This ensures dev shell users always have the required golang version.

Author: maru-ava

flake.nix

@@ -33,6 +33,9 @@
         default = pkgs.mkShell {
           # The Nix packages provided in the environment
           packages = with pkgs; [
+            # Local Go package
+            (import ./nix/go.nix { inherit pkgs; })
+
             # Monitoring tools
             promtail                                   # Loki log shipper
             prometheus                                 # Metrics collector
@@ -49,6 +52,14 @@
             # macOS-specific frameworks
             darwin.apple_sdk.frameworks.Security
           ];
+
+          shellHook = ''
+            # Ensure golang bin is in the path
+            GOBIN="$(go env GOPATH)/bin"
+            if [[ ":$PATH:" != *":$GOBIN:"* ]]; then
+              export PATH="$GOBIN:$PATH"
+            fi
+          '';
         };
       });
 

go.mod

@@ -3,6 +3,7 @@ module github.com/ava-labs/avalanchego
 // - Changes to the minimum golang version must also be replicated in:
 //   - CONTRIBUTING.md
 //   - README.md
+//   - nix/go.nix (update version and sha256 for supported arches)
 //   - go.mod (here)
 //
 // - If updating between minor versions (e.g. 1.23.x -> 1.24.x):

nix/go.nix

@@ -0,0 +1,50 @@
+{ pkgs }:
+let
+  # Helper functions to derive Go arch from Nix arch
+  nixArchToGoArch = arch: {
+    "x86_64" = "amd64";
+    "aarch64" = "arm64";
+  }.${arch} or arch;
+
+  # Split system into arch and os
+  parseSystem = system:
+    let
+      parts = builtins.split "-" system;
+      arch = builtins.elemAt parts 0;
+      os = builtins.elemAt parts 2;
+    in {
+      goarch = nixArchToGoArch arch;
+      goos = os;
+      goURLPath = "${os}-${nixArchToGoArch arch}";
+    };
+
+  # Update the following to change the version:
+  goVersion = "1.23.6";
+  goSHA256s = {
+    "linux-amd64" = "9379441ea310de000f33a4dc767bd966e72ab2826270e038e78b2c53c2e7802d";
+    "linux-arm64" = "561c780e8f4a8955d32bf72e46af0b5ee5e0debe1e4633df9a03781878219202";
+    "darwin-amd64" = "782da50ce8ec5e98fac2cd3cdc6a1d7130d093294fc310038f651444232a3fb0";
+    "darwin-arm64" = "5cae2450a1708aeb0333237a155640d5562abaf195defebc4306054565536221";
+  };
+
+  targetSystem = parseSystem pkgs.system;
+in
+pkgs.stdenv.mkDerivation {
+  name = "go-${goVersion}";
+  version = goVersion;
+
+  inherit (targetSystem) goos goarch;
+  GOOS = targetSystem.goos;
+  GOARCH = targetSystem.goarch;
+
+  src = pkgs.fetchurl {
+    url = "https://go.dev/dl/go${goVersion}.${targetSystem.goURLPath}.tar.gz";
+    sha256 = goSHA256s.${targetSystem.goURLPath} or (throw "Unsupported system: ${pkgs.system}");
+  };
+
+  installPhase = ''
+    mkdir -p $out
+    cp -r ./* $out/
+    chmod +x $out/bin/go
+  '';
+}