CLI: always try to exec binaries

Previously when using `zig run` or `zig test`, zig would try to guess
whether the host system was capable of running the target binaries. Now,
it will always try. If it fails, then Zig emits a helpful warning to
explain the probable cause.

1 files changed, 43 insertions, 28 deletions

diff --git a/lib/std/build.zig b/lib/std/build.zig
index 041510bb02..75e6db301e 100644
--- a/lib/std/build.zig
+++ b/lib/std/build.zig
@@ -2527,45 +2527,56 @@ pub const LibExeObjStep = struct {
                 }
             }
         } else switch (self.target.getExternalExecutor()) {
-            .native, .unavailable => {},
+            .native => {},
+            .unavailable => {
+                try zig_args.append("--test-no-exec");
+            },
             .rosetta => if (builder.enable_rosetta) {
                 try zig_args.append("--test-cmd-bin");
+            } else {
+                try zig_args.append("--test-no-exec");
             },
-            .qemu => |bin_name| if (builder.enable_qemu) qemu: {
-                const need_cross_glibc = self.target.isGnuLibC() and self.is_linking_libc;
-                const glibc_dir_arg = if (need_cross_glibc)
-                    builder.glibc_runtimes_dir orelse break :qemu
-                else
-                    null;
-                try zig_args.append("--test-cmd");
-                try zig_args.append(bin_name);
-                if (glibc_dir_arg) |dir| {
-                    // TODO look into making this a call to `linuxTriple`. This
-                    // needs the directory to be called "i686" rather than
-                    // "i386" which is why we do it manually here.
-                    const fmt_str = "{s}" ++ fs.path.sep_str ++ "{s}-{s}-{s}";
-                    const cpu_arch = self.target.getCpuArch();
-                    const os_tag = self.target.getOsTag();
-                    const abi = self.target.getAbi();
-                    const cpu_arch_name: []const u8 = if (cpu_arch == .i386)
-                        "i686"
+            .qemu => |bin_name| ok: {
+                if (builder.enable_qemu) qemu: {
+                    const need_cross_glibc = self.target.isGnuLibC() and self.is_linking_libc;
+                    const glibc_dir_arg = if (need_cross_glibc)
+                        builder.glibc_runtimes_dir orelse break :qemu
                     else
-                        @tagName(cpu_arch);
-                    const full_dir = try std.fmt.allocPrint(builder.allocator, fmt_str, .{
-                        dir, cpu_arch_name, @tagName(os_tag), @tagName(abi),
-                    });
-
+                        null;
                     try zig_args.append("--test-cmd");
-                    try zig_args.append("-L");
-                    try zig_args.append("--test-cmd");
-                    try zig_args.append(full_dir);
+                    try zig_args.append(bin_name);
+                    if (glibc_dir_arg) |dir| {
+                        // TODO look into making this a call to `linuxTriple`. This
+                        // needs the directory to be called "i686" rather than
+                        // "i386" which is why we do it manually here.
+                        const fmt_str = "{s}" ++ fs.path.sep_str ++ "{s}-{s}-{s}";
+                        const cpu_arch = self.target.getCpuArch();
+                        const os_tag = self.target.getOsTag();
+                        const abi = self.target.getAbi();
+                        const cpu_arch_name: []const u8 = if (cpu_arch == .i386)
+                            "i686"
+                        else
+                            @tagName(cpu_arch);
+                        const full_dir = try std.fmt.allocPrint(builder.allocator, fmt_str, .{
+                            dir, cpu_arch_name, @tagName(os_tag), @tagName(abi),
+                        });
+
+                        try zig_args.append("--test-cmd");
+                        try zig_args.append("-L");
+                        try zig_args.append("--test-cmd");
+                        try zig_args.append(full_dir);
+                    }
+                    try zig_args.append("--test-cmd-bin");
+                    break :ok;
                 }
-                try zig_args.append("--test-cmd-bin");
+                try zig_args.append("--test-no-exec");
             },
             .wine => |bin_name| if (builder.enable_wine) {
                 try zig_args.append("--test-cmd");
                 try zig_args.append(bin_name);
                 try zig_args.append("--test-cmd-bin");
+            } else {
+                try zig_args.append("--test-no-exec");
             },
             .wasmtime => |bin_name| if (builder.enable_wasmtime) {
                 try zig_args.append("--test-cmd");
@@ -2573,11 +2584,15 @@ pub const LibExeObjStep = struct {
                 try zig_args.append("--test-cmd");
                 try zig_args.append("--dir=.");
                 try zig_args.append("--test-cmd-bin");
+            } else {
+                try zig_args.append("--test-no-exec");
             },
             .darling => |bin_name| if (builder.enable_darling) {
                 try zig_args.append("--test-cmd");
                 try zig_args.append(bin_name);
                 try zig_args.append("--test-cmd-bin");
+            } else {
+                try zig_args.append("--test-no-exec");
             },
         }