build: create new build options per compile step

This is going to let us put more object-specific config into the options
rather than affecting every object build per build.

build.zig

@@ -159,7 +159,7 @@ pub fn build(b: *std.Build) !void {
             "If not specified, git will be used. This must be a semantic version.",
     );
 
-    const version: std.SemanticVersion = if (version_string) |v|
+    config.version = if (version_string) |v|
         try std.SemanticVersion.parse(v)
     else version: {
         const vsn = try Version.detect(b);
@@ -211,19 +211,8 @@ pub fn build(b: *std.Build) !void {
         .optimize = optimize,
     }) else null;
 
-    const exe_options = b.addOptions();
-    config.addOptions(exe_options);
-    exe_options.addOption(std.SemanticVersion, "app_version", version);
-    exe_options.addOption([:0]const u8, "app_version_string", try std.fmt.allocPrintZ(
-        b.allocator,
-        "{}",
-        .{version},
-    ));
-
     // Exe
     if (exe_) |exe| {
-        exe.root_module.addOptions("build_options", exe_options);
-
         // Add the shared dependencies
         _ = try addDeps(b, exe, config);
 
@@ -428,7 +417,7 @@ pub fn build(b: *std.Build) !void {
     }
 
     // Documenation
-    if (emit_docs) buildDocumentation(b, version);
+    if (emit_docs) buildDocumentation(b, config.version);
 
     // App (Linux)
     if (target.result.os.tag == .linux and config.app_runtime != .none) {
@@ -464,7 +453,6 @@ pub fn build(b: *std.Build) !void {
                 .optimize = optimize,
                 .target = target,
             });
-            lib.root_module.addOptions("build_options", exe_options);
             _ = try addDeps(b, lib, config);
 
             const lib_install = b.addInstallLibFile(
@@ -482,7 +470,6 @@ pub fn build(b: *std.Build) !void {
                 .optimize = optimize,
                 .target = target,
             });
-            lib.root_module.addOptions("build_options", exe_options);
             _ = try addDeps(b, lib, config);
 
             const lib_install = b.addInstallLibFile(
@@ -510,7 +497,6 @@ pub fn build(b: *std.Build) !void {
             b,
             optimize,
             config,
-            exe_options,
         );
 
         // Add our library to zig-out
@@ -526,7 +512,6 @@ pub fn build(b: *std.Build) !void {
             null,
             optimize,
             config,
-            exe_options,
         );
 
         // Add our library to zig-out
@@ -542,7 +527,6 @@ pub fn build(b: *std.Build) !void {
             .simulator,
             optimize,
             config,
-            exe_options,
         );
 
         // Add our library to zig-out
@@ -605,6 +589,11 @@ pub fn build(b: *std.Build) !void {
             }),
         };
 
+        // Whether we're using wasm shared memory. Some behaviors change.
+        // For now we require this but I wanted to make the code handle both
+        // up front.
+        const wasm_shared: bool = true;
+
         // Modify our build configuration for wasm builds.
         const wasm_config: BuildConfig = config: {
             var copy = config;
@@ -616,26 +605,19 @@ pub fn build(b: *std.Build) !void {
             // Backends that are fixed for wasm
             copy.font_backend = .web_canvas;
 
+            // Wasm-specific options
+            copy.wasm_shared = wasm_shared;
+            copy.wasm_target = wasm_target;
+
             break :config copy;
         };
 
-        // Whether we're using wasm shared memory. Some behaviors change.
-        // For now we require this but I wanted to make the code handle both
-        // up front.
-        const wasm_shared: bool = true;
-        exe_options.addOption(bool, "wasm_shared", wasm_shared);
-
-        // We want to support alternate wasm targets in the future (i.e.
-        // server side) so we have this now although its hardcoded.
-        exe_options.addOption(WasmTarget, "wasm_target", wasm_target);
-
         const wasm = b.addSharedLibrary(.{
             .name = "ghostty-wasm",
             .root_source_file = .{ .path = "src/main_wasm.zig" },
             .target = b.resolveTargetQuery(wasm_crosstarget),
             .optimize = optimize,
         });
-        wasm.root_module.addOptions("build_options", exe_options);
 
         // So that we can use web workers with our wasm binary
         wasm.import_memory = true;
@@ -666,7 +648,6 @@ pub fn build(b: *std.Build) !void {
             .target = b.resolveTargetQuery(wasm_crosstarget),
         });
 
-        main_test.root_module.addOptions("build_options", exe_options);
         _ = try addDeps(b, main_test, wasm_config);
         test_step.dependOn(&main_test.step);
     }
@@ -709,7 +690,6 @@ pub fn build(b: *std.Build) !void {
                 copy.static = true;
                 break :config copy;
             });
-            main_test.root_module.addOptions("build_options", exe_options);
 
             const test_run = b.addRunArtifact(main_test);
             test_step.dependOn(&test_run.step);
@@ -755,7 +735,6 @@ fn createMacOSLib(
     b: *std.Build,
     optimize: std.builtin.OptimizeMode,
     config: BuildConfig,
-    exe_options: *std.Build.Step.Options,
 ) !struct { *std.Build.Step, std.Build.LazyPath } {
     // Modify our build configuration for macOS builds.
     const macos_config: BuildConfig = config: {
@@ -781,7 +760,6 @@ fn createMacOSLib(
         });
         lib.bundle_compiler_rt = true;
         lib.linkLibC();
-        lib.root_module.addOptions("build_options", exe_options);
 
         // Create a single static lib with all our dependencies merged
         var lib_list = try addDeps(b, lib, macos_config);
@@ -810,7 +788,6 @@ fn createMacOSLib(
         });
         lib.bundle_compiler_rt = true;
         lib.linkLibC();
-        lib.root_module.addOptions("build_options", exe_options);
 
         // Create a single static lib with all our dependencies merged
         var lib_list = try addDeps(b, lib, macos_config);
@@ -847,7 +824,6 @@ fn createIOSLib(
     abi: ?std.Target.Abi,
     optimize: std.builtin.OptimizeMode,
     config: BuildConfig,
-    exe_options: *std.Build.Step.Options,
 ) !struct { *std.Build.Step, std.Build.LazyPath } {
     const ios_config: BuildConfig = config: {
         var copy = config;
@@ -868,7 +844,6 @@ fn createIOSLib(
     });
     lib.bundle_compiler_rt = true;
     lib.linkLibC();
-    lib.root_module.addOptions("build_options", exe_options);
 
     // Create a single static lib with all our dependencies merged
     var lib_list = try addDeps(b, lib, ios_config);
@@ -895,6 +870,11 @@ fn addDeps(
     step: *std.Build.Step.Compile,
     config: BuildConfig,
 ) !LazyPathList {
+    // All object targets get access to a standard build_options module
+    const exe_options = b.addOptions();
+    try config.addOptions(exe_options);
+    step.root_module.addOptions("build_options", exe_options);
+
     var static_libs = LazyPathList.init(b.allocator);
     errdefer static_libs.deinit();
 

src/build_config.zig

@@ -9,6 +9,7 @@ const assert = std.debug.assert;
 const apprt = @import("apprt.zig");
 const font = @import("font/main.zig");
 const rendererpkg = @import("renderer.zig");
+const WasmTarget = @import("os/wasm/target.zig").Target;
 
 /// The build configuratin options. This may not be all available options
 /// to `zig build` but it contains all the options that the Ghostty source
@@ -18,6 +19,7 @@ const rendererpkg = @import("renderer.zig");
 /// between options, make it easy to copy and mutate options for different
 /// build types, etc.
 pub const BuildConfig = struct {
+    version: std.SemanticVersion = .{ .major = 0, .minor = 0, .patch = 0 },
     static: bool = false,
     flatpak: bool = false,
     libadwaita: bool = false,
@@ -25,8 +27,14 @@ pub const BuildConfig = struct {
     renderer: rendererpkg.Impl = .opengl,
     font_backend: font.Backend = .freetype,
 
+    /// The target runtime for the wasm build and whether to use wasm shared
+    /// memory or not. These are both legacy wasm-specific options that we
+    /// will probably have to revisit when we get back to work on wasm.
+    wasm_target: WasmTarget = .browser,
+    wasm_shared: bool = true,
+
     /// Configure the build options with our values.
-    pub fn addOptions(self: BuildConfig, step: *std.Build.Step.Options) void {
+    pub fn addOptions(self: BuildConfig, step: *std.Build.Step.Options) !void {
         // We need to break these down individual because addOption doesn't
         // support all types.
         step.addOption(bool, "flatpak", self.flatpak);
@@ -34,6 +42,18 @@ pub const BuildConfig = struct {
         step.addOption(apprt.Runtime, "app_runtime", self.app_runtime);
         step.addOption(font.Backend, "font_backend", self.font_backend);
         step.addOption(rendererpkg.Impl, "renderer", self.renderer);
+        step.addOption(WasmTarget, "wasm_target", self.wasm_target);
+        step.addOption(bool, "wasm_shared", self.wasm_shared);
+
+        // Our version. We also add the string version so we don't need
+        // to do any allocations at runtime.
+        var buf: [64]u8 = undefined;
+        step.addOption(std.SemanticVersion, "app_version", self.version);
+        step.addOption([:0]const u8, "app_version_string", try std.fmt.bufPrintZ(
+            &buf,
+            "{}",
+            .{self.version},
+        ));
     }
 
     /// Rehydrate our BuildConfig from the comptime options. Note that not all
@@ -41,11 +61,14 @@ pub const BuildConfig = struct {
     /// to see what is and isn't available.
     pub fn fromOptions() BuildConfig {
         return .{
+            .version = options.app_version,
             .flatpak = options.flatpak,
             .libadwaita = options.libadwaita,
             .app_runtime = std.meta.stringToEnum(apprt.Runtime, @tagName(options.app_runtime)).?,
             .font_backend = std.meta.stringToEnum(font.Backend, @tagName(options.font_backend)).?,
             .renderer = std.meta.stringToEnum(rendererpkg.Impl, @tagName(options.renderer)).?,
+            .wasm_target = std.meta.stringToEnum(WasmTarget, @tagName(options.wasm_target)).?,
+            .wasm_shared = options.wasm_shared,
         };
     }
 };