From c761e1de4dcf87b9106e4f70cb89217a81aa2f9f Mon Sep 17 00:00:00 2001
From: Ophestra <cat@gensokyo.uk>
Date: Sat, 15 Nov 2025 16:27:34 +0900
Subject: [PATCH] nix: build with clang

Clang is better than gcc in various ways. This also pulls in clang-format which is very helpful.

Signed-off-by: Ophestra <cat@gensokyo.uk>
---
 flake.nix                      |  8 ++++++--
 internal/outcome/shim-signal.c |  2 +-
 package.nix                    | 13 +++++++++----
 test/default.nix               |  2 +-
 4 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/flake.nix b/flake.nix
index e158b50..109551b 100644
--- a/flake.nix
+++ b/flake.nix
@@ -114,7 +114,7 @@
             inherit (pkgs)
               # passthru.buildInputs
               go
-              gcc
+              clang
 
               # nativeBuildInputs
               pkg-config
@@ -129,6 +129,10 @@
               zstd
               gnutar
               coreutils
+
+              # for check
+              util-linux
+              nettools
               ;
           };
           hsu = pkgs.callPackage ./cmd/hsu/package.nix { inherit (self.packages.${system}) hakurei; };
@@ -144,7 +148,7 @@
                 && chmod -R +w .
 
             export HAKUREI_VERSION="v${hakurei.version}"
-            ./dist/release.sh && mkdir $out && cp -v "dist/hakurei-$HAKUREI_VERSION.tar.gz"* $out
+            CC="clang -O3 -Werror" ./dist/release.sh && mkdir $out && cp -v "dist/hakurei-$HAKUREI_VERSION.tar.gz"* $out
           '';
         }
       );
diff --git a/internal/outcome/shim-signal.c b/internal/outcome/shim-signal.c
index 7e56206..0e04abb 100644
--- a/internal/outcome/shim-signal.c
+++ b/internal/outcome/shim-signal.c
@@ -38,7 +38,7 @@ static void hakurei_shim_sigaction(int sig, siginfo_t *si, void *ucontext) {
 
 void hakurei_shim_setup_cont_signal(pid_t ppid, int fd) {
   if (hakurei_shim_param_ppid != -1 || hakurei_shim_fd != -1)
-    *(int *)NULL = 0; /* unreachable */
+    *(volatile int *)NULL = 0; /* unreachable */
 
   struct sigaction new_action = {0}, old_action = {0};
   if (sigaction(SIGCONT, NULL, &old_action) != 0)
diff --git a/package.nix b/package.nix
index 21aee35..fb449c1 100644
--- a/package.nix
+++ b/package.nix
@@ -20,7 +20,7 @@
 
   # for passthru.buildInputs
   go,
-  gcc,
+  clang,
 
   # for check
   util-linux,
@@ -81,8 +81,13 @@ buildGoModule rec {
         hsuPath = "/run/wrappers/bin/hsu";
       };
 
-  # nix build environment does not allow acls
-  env.GO_TEST_SKIP_ACL = 1;
+  env = {
+    # use clang instead of gcc
+    CC = "clang -O3 -Werror";
+
+    # nix build environment does not allow acls
+    GO_TEST_SKIP_ACL = 1;
+  };
 
   buildInputs = [
     libffi
@@ -135,7 +140,7 @@ buildGoModule rec {
 
   passthru.targetPkgs = [
     go
-    gcc
+    clang
     xorg.xorgproto
     util-linux
 
diff --git a/test/default.nix b/test/default.nix
index 037d7de..edca9fd 100644
--- a/test/default.nix
+++ b/test/default.nix
@@ -44,7 +44,7 @@ nixosTest {
 
           cd ${self.packages.${system}.hakurei.src}
           ${fhs}/bin/hakurei-fhs -c \
-            'go test ${if withRace then "-race" else "-count 16"} ./...' \
+            'CC="clang -O3 -Werror" go test ${if withRace then "-race" else "-count 16"} ./...' \
             &> /tmp/hakurei-test.log && \
             touch /tmp/hakurei-test-ok
           touch /tmp/hakurei-test-done