From 559fd922959905e12dabfdecf8b2a78db8ecda22 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <m@mitchellh.com>
Date: Tue, 17 Jun 2025 16:23:15 -0700
Subject: [PATCH] build: use `xcrun --sdk <sdk> metal` for metal paths

This wasn't working before but it just requires a restart of the machine
for the changes to take effect. The namespace runners have this prebuilt
so this should work now.

The other workaround was flaky for unknown reasons so I'd prefer to go
back to this.
---
 src/build/MetallibStep.zig | 33 +++++++--------------------------
 1 file changed, 7 insertions(+), 26 deletions(-)

diff --git a/src/build/MetallibStep.zig b/src/build/MetallibStep.zig
index bac3a72c5..b7405c496 100644
--- a/src/build/MetallibStep.zig
+++ b/src/build/MetallibStep.zig
@@ -22,10 +22,11 @@ step: *Step,
 output: LazyPath,
 
 pub fn create(b: *std.Build, opts: Options) ?*MetallibStep {
-    switch (opts.target.result.os.tag) {
-        .macos, .ios => {},
-        else => return null, // Only macOS and iOS are supported.
-    }
+    const sdk = switch (opts.target.result.os.tag) {
+        .macos => "macosx",
+        .ios => "iphoneos",
+        else => return null,
+    };
 
     const self = b.allocator.create(MetallibStep) catch @panic("OOM");
 
@@ -37,31 +38,11 @@ pub fn create(b: *std.Build, opts: Options) ?*MetallibStep {
         else => unreachable,
     };
 
-    // Find the metal and metallib executables. The Apple docs
-    // at the time of writing (June 2025) say to use
-    // `xcrun --sdk <sdk> metal` but this doesn't work with Xcode 26.
-    //
-    // I don't know if this is a bug but the xcodebuild approach also
-    // works with Xcode 15 so it seems safe to use this instead.
-    //
-    // Reported bug: FB17874042.
-    var code: u8 = undefined;
-    const metal_exe = std.mem.trim(u8, b.runAllowFail(
-        &.{ "xcodebuild", "-find-executable", "metal" },
-        &code,
-        .Ignore,
-    ) catch return null, "\r\n ");
-    const metallib_exe = std.mem.trim(u8, b.runAllowFail(
-        &.{ "xcodebuild", "-find-executable", "metallib" },
-        &code,
-        .Ignore,
-    ) catch return null, "\r\n ");
-
     const run_ir = RunStep.create(
         b,
         b.fmt("metal {s}", .{opts.name}),
     );
-    run_ir.addArgs(&.{ metal_exe, "-o" });
+    run_ir.addArgs(&.{ "/usr/bin/xcrun", "-sdk", sdk, "metal", "-o" });
     const output_ir = run_ir.addOutputFileArg(b.fmt("{s}.ir", .{opts.name}));
     run_ir.addArgs(&.{"-c"});
     for (opts.sources) |source| run_ir.addFileArg(source);
@@ -81,7 +62,7 @@ pub fn create(b: *std.Build, opts: Options) ?*MetallibStep {
         b,
         b.fmt("metallib {s}", .{opts.name}),
     );
-    run_lib.addArgs(&.{ metallib_exe, "-o" });
+    run_lib.addArgs(&.{ "/usr/bin/xcrun", "-sdk", sdk, "metallib", "-o" });
     const output_lib = run_lib.addOutputFileArg(b.fmt("{s}.metallib", .{opts.name}));
     run_lib.addFileArg(output_ir);
     run_lib.step.dependOn(&run_ir.step);