[wrangler] Fix modules-watch-stub injection when bundle:false (fixes …

.changeset/fix-modules-watch-stub-no-bundle.md

@@ -0,0 +1,11 @@
+---
+"wrangler": patch
+---
+
+[wrangler] Fix `No such module "wrangler:modules-watch"` crash when running `wrangler pages dev` with `no_bundle = true`
+
+When `bundle: false` (e.g. `"no_bundle": true` in `wrangler.json`, or `--no-bundle` flag), esbuild does not resolve imports inside injected files. Previously, `modules-watch-stub.js` was always injected whenever `watch: true`, regardless of the `bundle` option. This left `import "wrangler:modules-watch"` as an unresolved import in the output, causing a runtime crash in workerd: `Uncaught Error: No such module "wrangler:modules-watch"`.
+
+The fix is to only inject `modules-watch-stub.js` when `bundle: true`. When `bundle: false`, file-system watching is already handled via chokidar, so the esbuild-internal watch stub is not needed.
+
+Fixes #14845.

packages/wrangler/src/deployment-bundle/bundle.ts

@@ -317,7 +317,7 @@ export async function bundleWorker(
 		inject.push(...(result.inject ?? []));
 	}
 
-	if (watch) {
+	if (watch && bundle) {
 		// `esbuild` doesn't support returning `watch*` options from `onStart()`
 		// plugin callbacks. Instead, we define an empty virtual module that is
 		// imported in this injected module. Importing that module registers watchers.