From d074e67cb17b41f81715bf491047f0b4d9818ff1 Mon Sep 17 00:00:00 2001
From: Jeff Quast <contact@jeffquast.com>
Date: Mon, 28 Sep 2026 14:36:14 +0000
Subject: [PATCH] Fix the engine aborting on load after a rebuild

loadMicropolisMainModule passed Module.wasmBinary. Emscripten accepts
that option only when wasmBinary is listed in INCOMING_MODULE_JS_API, and
the current default list omits it, so a build made with the current
Emscripten aborted before anything ran:

    RuntimeError: Aborted(`Module.wasmBinary` was supplied but
    `wasmBinary` not included in INCOMING_MODULE_JS_API)

The committed artifacts predate that default, so the failure appears only
once `make install` regenerates them. The loader now takes the wasm from
locateFile, which reads micropolisengine.wasm from disk next to the glue.
---
 apps/micropolis/cli/wasm/sim.ts      |  6 +++---
 apps/micropolis/src/lib/wasm/node.ts | 15 +++++++--------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/apps/micropolis/cli/wasm/sim.ts b/apps/micropolis/cli/wasm/sim.ts
index c4d8b09c..90edef9a 100644
--- a/apps/micropolis/cli/wasm/sim.ts
+++ b/apps/micropolis/cli/wasm/sim.ts
@@ -10,7 +10,7 @@ import { createNoopJsCallback } from '../../src/lib/wasm/callbacks';
 import { loadMicropolisMainModule } from '../../src/lib/wasm/node';
 import { normalizeStructuredFormat, stringifyStructured } from '../lib/format.js';
 
-type Flags = { city?: string; ticks?: number; format?: string };
+type Flags = { city?: string; ticks?: number; format?: string; verbose?: boolean };
 
 function stringFlag(v: unknown, fallback: string): string {
 	return typeof v === 'string' && v.length > 0 ? v : fallback;
@@ -53,7 +53,7 @@ function summarize(
 async function runSmoke(flags: Flags) {
 	const ticks = numberFlag(flags.ticks, 10);
 	const city = stringFlag(flags.city, '/cities/haight.cty');
-	const engine = await loadMicropolisMainModule();
+	const engine = await loadMicropolisMainModule(flags.verbose ?? false);
 	const micropolis = new engine.Micropolis();
 	const cb = createNoopJsCallback(engine);
 	micropolis.setCallback(cb, {});
@@ -69,7 +69,7 @@ async function runSmoke(flags: Flags) {
 
 async function runInfo(flags: Flags) {
 	const city = stringFlag(flags.city, '/cities/haight.cty');
-	const engine = await loadMicropolisMainModule();
+	const engine = await loadMicropolisMainModule(flags.verbose ?? false);
 	const micropolis = new engine.Micropolis();
 	const cb = createNoopJsCallback(engine);
 	micropolis.setCallback(cb, {});
diff --git a/apps/micropolis/src/lib/wasm/node.ts b/apps/micropolis/src/lib/wasm/node.ts
index 7adf3e45..1d544a64 100644
--- a/apps/micropolis/src/lib/wasm/node.ts
+++ b/apps/micropolis/src/lib/wasm/node.ts
@@ -37,18 +37,18 @@ function isBrowserOnlyEngineError(error: unknown): boolean {
 	);
 }
 
-export async function loadMicropolisMainModule(): Promise<MainModule> {
+export async function loadMicropolisMainModule(verbose = false): Promise<MainModule> {
 	assertWasmArtifactsPresent();
-	const wasmBinary = toArrayBuffer(readFileSync(wasmPath));
 	const dataBinary = toArrayBuffer(readFileSync(dataPath));
+	const print = verbose ? (message: string) => console.log(message) : () => {};
+	const printErr = verbose ? (message: string) => console.error(message) : () => {};
 
 	try {
 		return (await initModule({
-			print: () => {},
-			printErr: () => {},
+			print,
+			printErr,
 			setStatus: () => {},
 			locateFile: (filename: string) => path.join(projectLib, filename),
-			wasmBinary,
 			getPreloadedPackage: () => dataBinary
 		})) as MainModule;
 	} catch (nodeError) {
@@ -66,11 +66,10 @@ export async function loadMicropolisMainModule(): Promise<MainModule> {
 		(globalThis as { process?: unknown }).process = undefined;
 
 		return (await initModule({
-			print: () => {},
-			printErr: () => {},
+			print,
+			printErr,
 			setStatus: () => {},
 			locateFile: (filename: string) => path.join(projectLib, filename),
-			wasmBinary,
 			getPreloadedPackage: () => dataBinary
 		})) as MainModule;
 	} finally {