Force re-build of all plugins on Miniflare#reload()

...regardless of whether options have changed or not, ensuring files
(e.g. scripts, .env files, WASM modules) are re-read from disk

Author: mrbbot

packages/core/src/index.ts

@@ -316,7 +316,7 @@ export class MiniflareCore<
   }
 
   readonly #initPromise: Promise<void>;
-  async #init(): Promise<void> {
+  async #init(reloadAll = false): Promise<void> {
     // The caller must eventually call #reload() at some point after #init()
     this.#ctx.log.debug("Initialising worker...");
 
@@ -365,13 +365,14 @@ export class MiniflareCore<
     // through execution. (NOTE: ??= will only assign on undefined, not false)
     this.#watching ??= options.CorePlugin.watch ?? false;
 
-    // Build compatibility manager, rebuild all plugins if compatibility data,
-    // root path or any limits have changed
+    // Build compatibility manager, rebuild all plugins if reloadAll is set,
+    // compatibility data, root path or any limits have changed
     const { compatibilityDate, compatibilityFlags, globalAsyncIO } =
       options.CorePlugin;
     let ctxUpdate =
       (this.#previousRootPath && this.#previousRootPath !== rootPath) ||
-      this.#previousGlobalAsyncIO !== globalAsyncIO;
+      this.#previousGlobalAsyncIO !== globalAsyncIO ||
+      reloadAll;
     this.#previousRootPath = rootPath;
 
     if (this.#compat) {
@@ -930,7 +931,10 @@ export class MiniflareCore<
 
   async reload(): Promise<void> {
     await this.#initPromise;
-    await this.#init();
+    // Force re-build of all plugins, regardless of whether options have changed
+    // or not. This ensures files (scripts, .env files, WASM modules, etc.) are
+    // re-read from disk.
+    await this.#init(/* reloadAll */ true);
     await this.#reload();
   }
 

packages/core/test/index.spec.ts

@@ -873,22 +873,35 @@ test("MiniflareCore: #watcherCallback: re-runs setup for script-providing plugin
 
 test("MiniflareCore: reload: reloads worker", async (t) => {
   const tmp = await useTmp(t);
+  const scriptPath = path.join(tmp, "worker.js");
   const wranglerConfigPath = path.join(tmp, "wrangler.toml");
+  await fs.writeFile(
+    scriptPath,
+    "export default { fetch: (req, env) => new Response(`1:${env.KEY}`) };"
+  );
   await fs.writeFile(wranglerConfigPath, '[vars]\nKEY = "value1"');
-  const mf = useMiniflare({ BindingsPlugin }, { wranglerConfigPath });
-  let globalScope = await mf.getGlobalScope();
-  t.is(globalScope.KEY, "value1");
+  const mf = useMiniflare(
+    { BindingsPlugin },
+    { modules: true, scriptPath, wranglerConfigPath }
+  );
+  let res = await mf.dispatchFetch("http://localhost/");
+  t.is(await res.text(), "1:value1");
 
-  // Change wrangler config, check not automatically reloaded (watch disabled)
+  // Change wrangler config and script, check not automatically reloaded
+  // (note watch is disabled)
+  await fs.writeFile(
+    scriptPath,
+    "export default { fetch: (req, env) => new Response(`2:${env.KEY}`) };"
+  );
   await fs.writeFile(wranglerConfigPath, '[vars]\nKEY = "value2"');
   await setTimeout(100);
-  globalScope = await mf.getGlobalScope();
-  t.is(globalScope.KEY, "value1");
+  res = await mf.dispatchFetch("http://localhost/");
+  t.is(await res.text(), "1:value1");
 
-  // Manually reload(), check config reloaded
+  // Manually reload(), check config and script reloaded
   await mf.reload();
-  globalScope = await mf.getGlobalScope();
-  t.is(globalScope.KEY, "value2");
+  res = await mf.dispatchFetch("http://localhost/");
+  t.is(await res.text(), "2:value2");
 });
 
 test("MiniflareCore: dispatches reload events", async (t) => {