Add Module.prototype.load for new Module() instances

src/bun.js/bindings/JSCommonJSModule.cpp

@@ -812,6 +812,16 @@ class JSCommonJSModulePrototype final : public JSC::JSNonFinalObject {
             clientData(vm)->builtinNames().requireNativeModulePrivateName(),
             0,
             jsFunctionRequireNativeModule, ImplementationVisibility::Public, NoIntrinsic, JSC::PropertyAttribute::ReadOnly | JSC::PropertyAttribute::DontDelete);
+
+        // `Module.prototype.load(filename)` — needed for packages like
+        // `requizzle` that construct `new Module(...)` directly and call
+        // `.load()` on it. Mirrors Node's cjs loader semantics.
+        this->putDirectBuiltinFunction(
+            vm,
+            globalObject,
+            JSC::Identifier::fromString(vm, "load"_s),
+            WebCore::commonJSModulePrototypeLoadCodeGenerator(vm),
+            0);
     }
 };
 

src/bun.js/modules/NodeModuleModule.cpp

@@ -765,16 +765,25 @@ JSC_DEFINE_CUSTOM_SETTER(setNodeModuleWrapper,
 
 static JSValue getModulePrototypeObject(VM& vm, JSObject* moduleObject)
 {
+    // `Module.prototype` must be the SAME object that sits in the prototype
+    // chain of instances created via `new Module(...)`. Otherwise, assigning
+    // `Module.prototype.foo = ...` won't affect instances, and methods added
+    // to the real instance prototype (e.g. `load`) won't be visible via
+    // `Module.prototype`. Packages like `requizzle` depend on this.
     auto* globalObject = defaultGlobalObject(moduleObject->globalObject());
-    auto prototype = constructEmptyObject(globalObject, globalObject->objectPrototype(), 2);
-
-    prototype->putDirectCustomAccessor(
-        vm, WebCore::clientData(vm)->builtinNames().requirePublicName(),
-        JSC::CustomGetterSetter::create(vm, getterRequireFunction,
-            setterRequireFunction),
-        0);
-
-    prototype->putDirect(vm, Identifier::fromString(vm, "_compile"_s), globalObject->modulePrototypeUnderscoreCompileFunction());
+    auto* structure = globalObject->CommonJSModuleObjectStructure();
+    auto* prototype = structure->storedPrototypeObject();
+
+    // Expose `require` on the public prototype. Instance-level `require` is
+    // set per-instance during module evaluation, so the prototype accessor
+    // is only hit for instances constructed outside the normal loader path.
+    if (!prototype->getDirect(vm, WebCore::clientData(vm)->builtinNames().requirePublicName())) {
+        prototype->putDirectCustomAccessor(
+            vm, WebCore::clientData(vm)->builtinNames().requirePublicName(),
+            JSC::CustomGetterSetter::create(vm, getterRequireFunction,
+                setterRequireFunction),
+            0);
+    }
 
     return prototype;
 }

src/js/builtins/CommonJS.ts

@@ -415,7 +415,40 @@
 
   return proxy;
 }
 
+// `Module.prototype.load(filename)` — used by packages like `requizzle` that
+// construct `new Module(...)` directly and expect Node's module-loader shape.
+// Mirrors Node's lib/internal/modules/cjs/loader.js `Module.prototype.load`.
+$visibility = "Private";
+export function modulePrototypeLoad(this: JSCommonJSModule, filename: string) {
+  if (this.loaded) {
+    throw new Error("Module already loaded");
+  }
+
+  const Module = require("node:module");
+  const path = require("node:path");
+  const fs = require("node:fs");
+
+  this.filename = filename;
+  this.paths = Module._nodeModulePaths(path.dirname(filename));
+
+  const ext = path.extname(filename);
+  const extensions = Module._extensions;
+  const handler = extensions[ext] || extensions[".js"];
+  handler.$call(extensions, this, filename);
+
+  this.loaded = true;
+}
+
+// `Module._extensions['.js']` — reads file, runs it through `module._compile`
+// (which honors the current (possibly overridden) `Module.wrap`).
+$visibility = "Private";
+export function modulePrototypeLoadJSExtension(this: any, module: JSCommonJSModule, filename: string) {
+  const fs = require("node:fs");
+  const content = fs.readFileSync(filename, "utf8");
+  module._compile(content, filename);
+}
+
 type WrapperMutate = (start: string, end: string) => void;
 export function getWrapperArrayProxy(onMutate: WrapperMutate) {
   const wrapper = ["(function(exports,require,module,__filename,__dirname){", "})"];

test/regression/issue/29253.test.ts

@@ -0,0 +1,173 @@
+// https://github.com/oven-sh/bun/issues/29253
+//
+// `new Module(id, parent)` produced an instance whose prototype
+// did not expose `Module.prototype.load(filename)`, so packages
+// that construct a module by hand and then call `.load()` on it
+// (the same pattern Node's internal cjs loader uses) threw:
+//
+//   TypeError: targetModule.load is not a function
+//
+// `requizzle` — a dependency of `jsdoc` — does exactly this
+// inside its `exports.load` helper, so `bun run .../jsdoc.js`
+// crashed before jsdoc got a chance to run.
+//
+// The fix adds `Module.prototype.load` as a real method on the
+// prototype shared by instances created via `new Module(...)`
+// and unifies `require("module").prototype` with that same
+// prototype, so patching one is reflected in the other (Node
+// semantics).
+import { expect, test } from "bun:test";
+import { bunEnv, bunExe, tempDir } from "harness";
+import Module from "node:module";
+
+test("Module.prototype.load is a function (#29253)", () => {
+  // The one the ticket is about: the stub on the instance prototype.
+  expect(typeof Module.prototype.load).toBe("function");
+
+  // An instance created via `new Module(...)` must inherit `.load`.
+  const m = new Module("/tmp/does-not-matter-29253.js", null);
+  expect(typeof m.load).toBe("function");
+});
+
+test("Module.prototype is the instance prototype (#29253)", () => {
+  // Node guarantees these are the same object — so patching
+  // `Module.prototype.foo` is visible on every instance. Several
+  // libraries (next.js, requizzle, etc.) rely on this.
+  const m = new Module("/tmp/does-not-matter-29253-proto.js", null);
+  expect(Object.getPrototypeOf(m)).toBe(Module.prototype);
+});
+
+test("new Module().load(filename) reads and evaluates the file (#29253)", async () => {
+  // Spawn a separate Bun so the test doesn't pollute its own
+  // require cache or Module.wrap state.
+  using dir = tempDir("issue-29253-load", {
+    "target.js": `
+      module.exports = { answer: 42, filename: __filename, dirname: __dirname };
+    `,
+    "driver.js": `
+      const Module = require("node:module");
+      const path = require("node:path");
+      const target = path.resolve(__dirname, "target.js");
+
+      const m = new Module(target, module);
+      m.load(target);
+
+      // After load(): the file has been read, wrapped, and
+      // executed. The module's exports must be the object the
+      // file assigned to module.exports, and the bookkeeping
+      // fields must be populated the way Node does.
+      console.log(JSON.stringify({
+        loaded: m.loaded,
+        filename: m.filename,
+        exports: m.exports,
+      }));
+    `,
+  });
+
+  await using proc = Bun.spawn({
+    cmd: [bunExe(), "driver.js"],
+    env: bunEnv,
+    cwd: String(dir),
+    stdout: "pipe",
+    stderr: "pipe",
+  });
+
+  const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
+
+  expect(stderr).not.toContain("TypeError");
+  expect(stderr).not.toContain("Error");
+  expect(exitCode).toBe(0);
+
+  const result = JSON.parse(stdout.trim());
+  expect(result.loaded).toBe(true);
+  expect(result.filename).toMatch(/target\.js$/);
+  expect(result.exports.answer).toBe(42);
+  expect(result.exports.filename).toBe(result.filename);
+});
+
+test("Module.prototype.load honors an overridden Module.wrapper (#29253)", async () => {
+  // `load()` must compile the file through the CURRENT module
+  // wrapper (`Module.wrapper[0] + source + Module.wrapper[1]`)
+  // — not a hard-coded one. Mutating the wrapper array is how
+  // Bun exposes Node's wrapper-override hook.
+  using dir = tempDir("issue-29253-wrap", {
+    "target.js": `module.exports = { wrappedVar: typeof __swizzled };`,
+    "driver.js": `
+      const Module = require("node:module");
+      const path = require("node:path");
+      const originalWrapper0 = Module.wrapper[0];
+
+      // Inject a local 'const __swizzled = 1;' at the top of
+      // the module scope; if the wrapper is honored, the module
+      // sees typeof __swizzled === "number".
+      Module.wrapper[0] = originalWrapper0 + "const __swizzled = 1;\\n";
+
+      try {
+        const target = path.resolve(__dirname, "target.js");
+        const m = new Module(target, module);
+        m.load(target);
+        console.log(m.exports.wrappedVar);
+      } finally {
+        Module.wrapper[0] = originalWrapper0;
+      }
+    `,
+  });
+
+  await using proc = Bun.spawn({
+    cmd: [bunExe(), "driver.js"],
+    env: bunEnv,
+    cwd: String(dir),
+    stdout: "pipe",
+    stderr: "pipe",
+  });
+
+  const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
+
+  expect(stderr).not.toContain("TypeError");
+  expect(stderr).not.toContain("ReferenceError");
+  expect(exitCode).toBe(0);
+  expect(stdout.trim()).toBe("number");
+});
+
+test("new Module().load populates filename/paths/loaded (#29253)", async () => {
+  // Node's `Module.prototype.load` writes `filename`, `paths`,
+  // and `loaded` before returning. `requizzle` and any other
+  // package that reads those fields after `.load()` depends on
+  // this, even if it doesn't touch the wrapper.
+  using dir = tempDir("issue-29253-fields", {
+    "leaf.js": `module.exports = 'ok';`,
+    "driver.js": `
+      const Module = require("node:module");
+      const path = require("node:path");
+
+      const target = path.resolve(__dirname, "leaf.js");
+      const m = new Module(target, module);
+
+      // Pre-load state: loaded=false, no filename.
+      if (m.loaded !== false) throw new Error("pre-load 'loaded' should be false, got " + m.loaded);
+
+      m.load(target);
+
+      if (m.loaded !== true) throw new Error("post-load 'loaded' should be true");
+      if (m.filename !== target) throw new Error("filename mismatch: " + m.filename);
+      if (!Array.isArray(m.paths)) throw new Error("paths should be an array");
+      if (m.exports !== 'ok') throw new Error("exports mismatch: " + m.exports);
+      console.log("ok");
+    `,
+  });
+
+  await using proc = Bun.spawn({
+    cmd: [bunExe(), "driver.js"],
+    env: bunEnv,
+    cwd: String(dir),
+    stdout: "pipe",
+    stderr: "pipe",
+  });
+
+  const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
+
+  expect(stderr).not.toContain("TypeError");
+  expect(stderr).not.toContain("Error:");
+  expect(exitCode).toBe(0);
+  expect(stdout.trim()).toBe("ok");
+});