fix(apps): resolve deno-runtime module not found after upgrade (#40947)

Author: dsaicharan072-cmyk

.changeset/fix-deno-runtime-symlink.md

@@ -0,0 +1,5 @@
+---
+'@rocket.chat/apps': patch
+---
+
+Fixes an issue that would cause apps to fail with 'Module not found' errors in some cases

packages/apps/src/server/runtime/deno/AppsEngineDenoRuntime.ts

@@ -47,6 +47,38 @@ function generateEphemeralDenoConfig(targetPath: string, denoConfigPath: string,
 	fs.writeFileSync(targetPath, JSON.stringify(runtimeConfig, null, '\t'));
 }
 
+/**
+ * Ensures a directory symlink exists at `symlinkPath` pointing to `targetPath`.
+ *
+ * First removes whatever currently lives at `symlinkPath` (broken symlink,
+ * wrong target, or a non-symlink entry), ignoring ENOENT if nothing is there.
+ * Then creates the symlink, catching EEXIST to guard against race conditions.
+ */
+export function ensureSymlink(symlinkPath: string, targetPath: string): void {
+	try {
+		const currentTarget = fs.readlinkSync(symlinkPath);
+
+		if (currentTarget === targetPath) {
+			return;
+		}
+
+		fs.rmSync(symlinkPath, { recursive: true, force: true });
+	} catch (err: unknown) {
+		if ((err as NodeJS.ErrnoException).code !== 'ENOENT') {
+			fs.rmSync(symlinkPath, { recursive: true, force: true });
+		}
+	}
+
+	// Create the symlink; guard against a concurrent creator
+	try {
+		fs.symlinkSync(targetPath, symlinkPath, 'dir');
+	} catch (err: unknown) {
+		if ((err as NodeJS.ErrnoException).code !== 'EEXIST') {
+			throw err;
+		}
+	}
+}
+
 export class DenoRuntimeSubprocessController extends BaseRuntimeSubprocessController {
 	private readonly denoBin = 'deno';
 
@@ -75,13 +107,7 @@ export class DenoRuntimeSubprocessController extends BaseRuntimeSubprocessContro
 		 * Deno 2.x refuses to run scripts inside the node_modules, so we create a symlink to the deno runtime files in the temp directory
 		 * The temp directory is the same we are given by the host to store temporary upload files
 		 */
-		try {
-			fs.symlinkSync(path.dirname(this.denoConfigPath), path.dirname(this.denoRuntimePath), 'dir');
-		} catch (reason: unknown) {
-			if ((reason as NodeJS.ErrnoException).code !== 'EEXIST') {
-				throw reason;
-			}
-		}
+		ensureSymlink(path.dirname(this.denoRuntimePath), path.dirname(this.denoConfigPath));
 
 		// Generate a runtime config with the resolved absolute path for @rocket.chat/apps-engine/ and @rocket.chat/apps/ paths
 		generateEphemeralDenoConfig(this.denoEphemeralConfigPath, this.denoConfigPath, this.appsEnginePath, this.packagePath);