allow resolving unenv aliases to packages (#11083)

Author: vicb

.changeset/petite-rules-kneel.md

@@ -0,0 +1,5 @@
+---
+"@cloudflare/vite-plugin": patch
+---
+
+allow resolving unenv aliases to packages

packages/vite-plugin-cloudflare/src/plugins/nodejs-compat.ts

@@ -403,15 +403,24 @@ export class NodeJsCompat {
 	): { unresolved: string; resolved: string } | undefined {
 		const alias = this.#env.alias[source];
 
-		// These aliases must be resolved from the context of this plugin since the alias will refer to one of the
-		// `@cloudflare/unenv-preset` or the `unenv` packages, which are direct dependencies of this package,
-		// and not the user's project.
 		// We exclude `externals` as these should be externalized rather than optimized.
 		if (alias && !this.externals.has(alias)) {
-			return {
-				unresolved: alias,
-				resolved: resolvePathSync(alias, { url: import.meta.url }),
-			};
+			try {
+				// These aliases must be resolved from the context of this plugin since the alias can refer to one of
+				// the `@cloudflare/unenv-preset` or the `unenv` packages, which are direct dependencies of this package,
+				// and not the user's project.
+				// When the alias is a package (i.e. the `debug` npm package), `resolvePathSync` will throw
+				return {
+					unresolved: alias,
+					resolved: resolvePathSync(alias, { url: import.meta.url }),
+				};
+			} catch {
+				// Returns the raw alias when it can not be resolved.
+				return {
+					unresolved: source,
+					resolved: alias,
+				};
+			}
 		}
 
 		if (this.entries.has(source)) {