Faster debug builds (#16354)

build.zig

@@ -200,7 +200,10 @@ pub fn build(b: *Build) !void {
         b.option([]const u8, "codegen_path", "Set the generated code directory") orelse
             "build/debug/codegen",
     );
-    const codegen_embed = b.option(bool, "codegen_embed", "If codegen files should be embedded in the binary") orelse false;
+    const codegen_embed = b.option(bool, "codegen_embed", "If codegen files should be embedded in the binary") orelse switch (b.release_mode) {
+        .off => false,
+        else => true,
+    };
 
     const bun_version = b.option([]const u8, "version", "Value of `Bun.version`") orelse "0.0.0";
 
@@ -527,36 +530,36 @@ fn addInternalPackages(b: *Build, obj: *Compile, opts: *BunBuildOptions) void {
         .{ .file = "ZigGeneratedClasses.zig", .import = "ZigGeneratedClasses" },
         .{ .file = "ResolvedSourceTag.zig", .import = "ResolvedSourceTag" },
         .{ .file = "ErrorCode.zig", .import = "ErrorCode" },
-        .{ .file = "runtime.out.js" },
+        .{ .file = "runtime.out.js", .enable = opts.shouldEmbedCode() },
         .{ .file = "bake.client.js", .import = "bake-codegen/bake.client.js", .enable = opts.shouldEmbedCode() },
         .{ .file = "bake.error.js", .import = "bake-codegen/bake.error.js", .enable = opts.shouldEmbedCode() },
         .{ .file = "bake.server.js", .import = "bake-codegen/bake.server.js", .enable = opts.shouldEmbedCode() },
         .{ .file = "bun-error/index.js", .enable = opts.shouldEmbedCode() },
         .{ .file = "bun-error/bun-error.css", .enable = opts.shouldEmbedCode() },
         .{ .file = "fallback-decoder.js", .enable = opts.shouldEmbedCode() },
-        .{ .file = "node-fallbacks/assert.js" },
-        .{ .file = "node-fallbacks/buffer.js" },
-        .{ .file = "node-fallbacks/console.js" },
-        .{ .file = "node-fallbacks/constants.js" },
-        .{ .file = "node-fallbacks/crypto.js" },
-        .{ .file = "node-fallbacks/domain.js" },
-        .{ .file = "node-fallbacks/events.js" },
-        .{ .file = "node-fallbacks/http.js" },
-        .{ .file = "node-fallbacks/https.js" },
-        .{ .file = "node-fallbacks/net.js" },
-        .{ .file = "node-fallbacks/os.js" },
-        .{ .file = "node-fallbacks/path.js" },
-        .{ .file = "node-fallbacks/process.js" },
-        .{ .file = "node-fallbacks/punycode.js" },
-        .{ .file = "node-fallbacks/querystring.js" },
-        .{ .file = "node-fallbacks/stream.js" },
-        .{ .file = "node-fallbacks/string_decoder.js" },
-        .{ .file = "node-fallbacks/sys.js" },
-        .{ .file = "node-fallbacks/timers.js" },
-        .{ .file = "node-fallbacks/tty.js" },
-        .{ .file = "node-fallbacks/url.js" },
-        .{ .file = "node-fallbacks/util.js" },
-        .{ .file = "node-fallbacks/zlib.js" },
+        .{ .file = "node-fallbacks/assert.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/buffer.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/console.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/constants.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/crypto.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/domain.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/events.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/http.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/https.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/net.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/os.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/path.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/process.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/punycode.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/querystring.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/stream.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/string_decoder.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/sys.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/timers.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/tty.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/url.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/util.js", .enable = opts.shouldEmbedCode() },
+        .{ .file = "node-fallbacks/zlib.js", .enable = opts.shouldEmbedCode() },
     }) |entry| {
         if (!@hasField(@TypeOf(entry), "enable") or entry.enable) {
             const path = b.pathJoin(&.{ opts.codegen_path, entry.file });

entitlements.debug.plist

@@ -2,19 +2,19 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
-    <key>com.apple.security.cs.allow-jit</key>
-    <true/>
-    <key>com.apple.security.cs.allow-unsigned-executable-memory</key>
-    <true/>
-    <key>com.apple.security.cs.disable-executable-page-protection</key>
-    <true/>
-    <key>com.apple.security.cs.allow-dyld-environment-variables</key>
-    <true/>
-    <key>com.apple.security.cs.disable-library-validation</key>
-    <true/>
-    <key>com.apple.security.get-task-allow</key>
-    <true/>
-    <key>com.apple.security.cs.debugger</key>
-    <true/>
+	<key>com.apple.security.cs.allow-jit</key>
+	<true/>
+	<key>com.apple.security.cs.allow-unsigned-executable-memory</key>
+	<true/>
+	<key>com.apple.security.cs.disable-executable-page-protection</key>
+	<true/>
+	<key>com.apple.security.cs.allow-dyld-environment-variables</key>
+	<true/>
+	<key>com.apple.security.cs.disable-library-validation</key>
+	<true/>
+	<key>com.apple.security.get-task-allow</key>
+	<true/>
+	<key>com.apple.security.cs.debugger</key>
+	<true/>
 </dict>
 </plist>

packages/bun-types/bun.d.ts

@@ -1233,13 +1233,13 @@ declare module "bun" {
 
     /**
      * Deletes the file. ( same as unlink )
-    */
-    delete(): Promise<void>
+     */
+    delete(): Promise<void>;
 
     /**
      *  Provides useful information about the file.
-    */
-    stat(): Promise<Stats>
+     */
+    stat(): Promise<Stats>;
   }
   interface NetworkSink extends FileSink {
     /**

src/bun.js/module_loader.zig

@@ -2496,7 +2496,7 @@ pub const ModuleLoader = struct {
         if (specifier.eqlComptime(Runtime.Runtime.Imports.Name)) {
             return ResolvedSource{
                 .allocator = null,
-                .source_code = String.init(Runtime.Runtime.source_code),
+                .source_code = String.init(Runtime.Runtime.sourceCode()),
                 .specifier = specifier,
                 .source_url = specifier,
                 .hash = Runtime.Runtime.versionHash(),

src/codegen/bake-codegen.ts

@@ -1,7 +1,7 @@
 import assert from "node:assert";
-import { existsSync, writeFileSync, rmSync, readFileSync } from "node:fs";
+import { existsSync, readFileSync, rmSync } from "node:fs";
 import { basename, join } from "node:path";
-import { argParse } from "./helpers";
+import { argParse, writeIfNotChanged } from "./helpers";
 
 // arg parsing
 let { "codegen-root": codegenRoot, debug, ...rest } = argParse(["codegen-root", "debug"]);
@@ -28,7 +28,7 @@ function convertZigEnum(zig: string) {
 
 async function run() {
   const devServerZig = readFileSync(join(base_dir, "DevServer.zig"), "utf-8");
-  writeFileSync(join(base_dir, "generated.ts"), convertZigEnum(devServerZig));
+  writeIfNotChanged(join(base_dir, "generated.ts"), convertZigEnum(devServerZig));
 
   const results = await Promise.allSettled(
     ["client", "server", "error"].map(async file => {
@@ -69,7 +69,7 @@ async function run() {
           `;
       const generated_entrypoint = join(base_dir, `.runtime-${file}.generated.ts`);
 
-      writeFileSync(generated_entrypoint, combined_source);
+      writeIfNotChanged(generated_entrypoint, combined_source);
 
       result = await Bun.build({
         entrypoints: [generated_entrypoint],
@@ -124,7 +124,7 @@ async function run() {
         }
       }
 
-      writeFileSync(join(codegenRoot, `bake.${file}.js`), code);
+      writeIfNotChanged(join(codegenRoot, `bake.${file}.js`), code);
     }),
   );
 
@@ -169,7 +169,7 @@ async function run() {
     console.log("-> bake.client.js, bake.server.js, bake.error.js");
 
     const empty_file = join(codegenRoot, "bake_empty_file");
-    if (!existsSync(empty_file)) writeFileSync(empty_file, "this is used to fulfill a cmake dependency");
+    if (!existsSync(empty_file)) writeIfNotChanged(empty_file, "this is used to fulfill a cmake dependency");
   }
 }
 

src/js/node/stream.ts

@@ -5258,18 +5258,10 @@ function createNativeStreamReadable(Readable) {
   var handleNumberResult = function (nativeReadable, result, view, isClosed) {
     if (result > 0) {
       const slice = view.subarray(0, result);
-      const remainder = view.subarray(result);
+      view = slice.byteLength < view.byteLength ? view.subarray(result) : undefined;
       if (slice.byteLength > 0) {
         nativeReadable.push(slice);
       }
-
-      if (isClosed) {
-        ProcessNextTick(() => {
-          nativeReadable.push(null);
-        });
-      }
-
-      return remainder.byteLength > 0 ? remainder : undefined;
     }
 
     if (isClosed) {

src/node_fallbacks.zig

@@ -17,7 +17,24 @@ comptime {
 pub const FallbackModule = struct {
     path: Fs.Path,
     package_json: *const PackageJSON,
-    code: string,
+    code: *const fn () string,
+
+    // This workaround exists to allow bun.runtimeEmbedFile to work.
+    // Using `@embedFile` forces you to wait for the Zig build to finish in
+    // debug builds, even when you only changed JS builtins.
+    fn createSourceCodeGetter(comptime code_path: string) *const fn () string {
+        const Getter = struct {
+            fn get() string {
+                if (bun.Environment.codegen_embed) {
+                    return @embedFile(code_path);
+                }
+
+                return bun.runtimeEmbedFile(.codegen_eager, code_path);
+            }
+        };
+
+        return Getter.get;
+    }
 
     pub fn init(comptime name: string) FallbackModule {
         @setEvalBranchQuota(99999);
@@ -35,7 +52,7 @@ pub const FallbackModule = struct {
                 .source = logger.Source.initPathString(import_path ++ name ++ "/package.json", ""),
                 .side_effects = .false,
             },
-            .code = @embedFile(code_path),
+            .code = createSourceCodeGetter(code_path),
         };
     }
 };
@@ -74,7 +91,7 @@ pub fn contentsFromPath(path: string) ?string {
     module_name = module_name[0 .. std.mem.indexOfScalar(u8, module_name, '/') orelse module_name.len];
 
     if (Map.get(module_name)) |mod| {
-        return mod.code;
+        return mod.code();
     }
 
     return null;

src/runtime.zig

@@ -149,12 +149,15 @@ pub const Fallback = struct {
 };
 
 pub const Runtime = struct {
-    pub const source_code = @embedFile("runtime.out.js");
-    pub const hash = brk: {
-        @setEvalBranchQuota(source_code.len * 50);
-        break :brk bun.Wyhash11.hash(0, source_code);
-    };
+    pub fn sourceCode() string {
+        return if (Environment.codegen_embed)
+            @embedFile("runtime.out.js")
+        else
+            bun.runtimeEmbedFile(.src_eager, "runtime.out.js");
+    }
+
     pub fn versionHash() u32 {
+        const hash = bun.Wyhash11.hash(0, sourceCode());
         return @truncate(hash);
     }