From 89ff10d568522e7a64a3a8e5dbe9e873a17eff4f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Thu, 17 Sep 2026 00:34:37 +0200
Subject: [PATCH] test: only run test-libc-nsz in debug mode

libzigc uses compilerRtOptMode(), so is always either small or fast. As such, we
don't get much value from running these tests in all optimize modes. debug seems
like the sensible choice to make the tests more debuggable.
---
 test/src/Libc.zig | 119 ++++++++++++++++++++++++----------------------
 1 file changed, 61 insertions(+), 58 deletions(-)

diff --git a/test/src/Libc.zig b/test/src/Libc.zig
index 6474fc43fed2f3a58b4bd5fe2d67d91b6cf145b3..9a87d922acb2675131f70243a20edc6ca34ce1f7 100644
--- a/test/src/Libc.zig
+++ b/test/src/Libc.zig
@@ -44,6 +44,11 @@ pub fn addLibcTestCase(
 }
 
 pub fn addTarget(libc: *const Libc, target: std.Build.ResolvedTarget) void {
+    const want_debug = for (libc.options.optimize_modes) |m| {
+        if (m == .debug) break true;
+    } else false;
+    if (!want_debug) return;
+
     if (libc.options.skip_wasm and target.query.cpu_arch != null and target.query.cpu_arch.?.isWasm()) return;
 
     if (libc.options.test_target_filters.len > 0) {
@@ -55,73 +60,71 @@ pub fn addTarget(libc: *const Libc, target: std.Build.ResolvedTarget) void {
 
     const common = libc.libc_test_src_path.path(libc.b, "common");
 
-    for (libc.options.optimize_modes) |optimize| {
-        const libtest_mod = libc.b.createModule(.{
+    const libtest_mod = libc.b.createModule(.{
+        .target = target,
+        .optimize = .debug,
+        .link_libc = true,
+    });
+
+    const libtest_c_source_files: []const []const u8 = &.{
+        "print.c", "rand.c", "mtest.c", "setrlim.c", "memfill.c", "vmfill.c", "fdfill.c", "utf8.c",
+    };
+    libtest_mod.addCSourceFiles(.{
+        .root = common,
+        .files = libtest_c_source_files[0..if (target.result.isMuslLibC()) 8 else 3],
+        .flags = &.{"-fno-builtin"},
+    });
+
+    const libtest = libc.b.addLibrary(.{
+        .name = "test",
+        .root_module = libtest_mod,
+    });
+
+    for (libc.test_cases.items) |*test_case| {
+        if (target.result.isWasiLibC() and !test_case.supports_wasi_libc)
+            continue;
+
+        const annotated_case_name = libc.b.fmt("run libc-test {s}", .{test_case.name});
+        for (libc.options.test_filters) |test_filter| {
+            if (std.mem.find(u8, annotated_case_name, test_filter)) |_| break;
+        } else if (libc.options.test_filters.len > 0) continue;
+
+        const mod = libc.b.createModule(.{
             .target = target,
-            .optimize = optimize,
+            .optimize = .debug,
             .link_libc = true,
         });
-
-        var libtest_c_source_files: []const []const u8 = &.{
-            "print.c", "rand.c", "mtest.c", "setrlim.c", "memfill.c", "vmfill.c", "fdfill.c", "utf8.c",
-        };
-        libtest_mod.addCSourceFiles(.{
-            .root = common,
-            .files = libtest_c_source_files[0..if (target.result.isMuslLibC()) 8 else 3],
+        mod.addIncludePath(common);
+        if (target.result.isWasiLibC())
+            mod.addCMacro("_WASI_EMULATED_SIGNAL", "");
+        mod.addCSourceFile(.{
+            .file = test_case.src_file,
             .flags = &.{"-fno-builtin"},
         });
-
-        const libtest = libc.b.addLibrary(.{
-            .name = "test",
-            .root_module = libtest_mod,
-        });
-
-        for (libc.test_cases.items) |*test_case| {
-            if (target.result.isWasiLibC() and !test_case.supports_wasi_libc)
-                continue;
-
-            const annotated_case_name = libc.b.fmt("run libc-test {s} ({t})", .{ test_case.name, optimize });
-            for (libc.options.test_filters) |test_filter| {
-                if (std.mem.find(u8, annotated_case_name, test_filter)) |_| break;
-            } else if (libc.options.test_filters.len > 0) continue;
-
-            const mod = libc.b.createModule(.{
-                .target = target,
-                .optimize = optimize,
-                .link_libc = true,
-            });
-            mod.addIncludePath(common);
-            if (target.result.isWasiLibC())
-                mod.addCMacro("_WASI_EMULATED_SIGNAL", "");
+        if (test_case.additional_src_file) |additional_src_file| {
             mod.addCSourceFile(.{
-                .file = test_case.src_file,
+                .file = additional_src_file,
                 .flags = &.{"-fno-builtin"},
             });
-            if (test_case.additional_src_file) |additional_src_file| {
-                mod.addCSourceFile(.{
-                    .file = additional_src_file,
-                    .flags = &.{"-fno-builtin"},
-                });
-            }
-            mod.linkLibrary(libtest);
-
-            const exe = libc.b.addExecutable(.{
-                .name = test_case.name,
-                .root_module = mod,
-                .max_rss = libc.options.max_rss,
-            });
-
-            const run = libc.b.addRunArtifact(exe);
-            run.setName(annotated_case_name);
-            run.skip_foreign_checks = true;
-            run.disable_zig_progress = true; // can interfere with fd count assumptions
-            run.expectStdErrEqual("");
-            run.expectStdOutEqual("");
-            run.expectExitCode(0);
-            run.step.max_rss = libc.options.max_rss;
-
-            libc.root_step.dependOn(&run.step);
         }
+        mod.linkLibrary(libtest);
+
+        const exe = libc.b.addExecutable(.{
+            .name = test_case.name,
+            .root_module = mod,
+            .max_rss = libc.options.max_rss,
+        });
+
+        const run = libc.b.addRunArtifact(exe);
+        run.setName(annotated_case_name);
+        run.skip_foreign_checks = true;
+        run.disable_zig_progress = true; // can interfere with fd count assumptions
+        run.expectStdErrEqual("");
+        run.expectStdOutEqual("");
+        run.expectExitCode(0);
+        run.step.max_rss = libc.options.max_rss;
+
+        libc.root_step.dependOn(&run.step);
     }
 }
 
-- 
2.54.0