fix: refactor formatExceptionMessage to accept generic request context (#2877)

- Renamed `renderingRequest` parameter to `requestDescription` in
`formatExceptionMessage`
- Changed the hardcoded label from `"JS code for rendering request
was:"` to the neutral `"Request:"`
- Updated JSDoc to reflect the broader usage

Closes #2858

`formatExceptionMessage` was originally written for the render endpoint
and hardcoded the label `"JS code for rendering request was:"`. Since
the `/upload-assets` endpoint now also calls it (via lock-failure
handling) with a task description string like `"Uploading bundles
[server.js] with assets [stats.json]"`, this produced misleading error
logs. The fix uses a generic label that works for both use cases.

All 11 call sites already pass a `string`, so no caller changes were
needed.

- [x] TypeScript type-check passes (`pnpm run --filter
react-on-rails-pro-node-renderer type-check`)
- [x] ESLint passes on the changed file
- [x] Package builds successfully (`pnpm run --filter
react-on-rails-pro-node-renderer build`)
- [x] Verified all 11 call sites — no caller changes required

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

* **Bug Fixes**
* Improved rendering error messages to clearly show the request context,
choosing a descriptive label when a JS rendering snippet is present or
using a provided custom label/content.
  * Simplified the default label to "Request:" where applicable.
* Trimmed and cleaned surrounding whitespace/newlines so error snippets
and overall output are easier to read.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

packages/react-on-rails-pro-node-renderer/src/shared/utils.ts

@@ -65,16 +65,20 @@ export function errorResponseResult(msg: string, tracingContext?: TracingContext
   return badRequestResponseResult(msg);
 }
 
+export type RequestInfo = { renderingRequest: string } | { label: string; content: string };
 /**
- * @param renderingRequest The JavaScript code which threw an error
+ * @param request Either a rendering request (auto-labeled) or a { label, content } pair
  * @param error The error that was thrown (typed as `unknown` to minimize casts in `catch`)
  * @param context Optional context to include in the error message
  */
-export function formatExceptionMessage(renderingRequest: string, error: unknown, context?: string) {
+export function formatExceptionMessage(request: RequestInfo, error: unknown, context?: string) {
+  const label = 'renderingRequest' in request ? 'JS code for rendering request was:' : request.label;
+  const content = 'renderingRequest' in request ? request.renderingRequest : request.content;
+
   return `${context ? `\nContext:\n${context}\n` : ''}
-JS code for rendering request was:
-${smartTrim(renderingRequest)}
-    
+${label}
+${smartTrim(content)}
+
 EXCEPTION MESSAGE:
 ${(error as Error).message || error}
 

packages/react-on-rails-pro-node-renderer/src/worker.ts

@@ -367,15 +367,15 @@ export default function run(config: Partial<Config>) {
           await setResponse(result.response, res);
         } catch (err) {
           const exceptionMessage = formatExceptionMessage(
-            renderingRequest,
+            { renderingRequest },
             err,
             'UNHANDLED error in handleRenderRequest',
           );
           await setResponse(errorResponseResult(exceptionMessage, context), res);
         }
       }, startSsrRequestOptions({ renderingRequest }));
     } catch (theErr) {
-      const exceptionMessage = formatExceptionMessage(renderingRequest, theErr);
+      const exceptionMessage = formatExceptionMessage({ renderingRequest }, theErr);
       await setResponse(errorResponseResult(`Unhandled top level error: ${exceptionMessage}`), res);
     }
   });
@@ -546,7 +546,11 @@ export default function run(config: Partial<Config>) {
       // endpoint so that concurrent /upload-assets and render requests
       // targeting the same bundle directory are mutually exclusive.
       // See https://github.com/shakacode/react_on_rails/issues/2463
-      const result = await handleNewBundlesProvided(taskDescription, providedNewBundles, assetsToCopy);
+      const result = await handleNewBundlesProvided(
+        { label: 'Request:', content: taskDescription },
+        providedNewBundles,
+        assetsToCopy,
+      );
       if (result) {
         await setResponse(result, res);
         return;

packages/react-on-rails-pro-node-renderer/src/worker/handleRenderRequest.ts

@@ -22,6 +22,7 @@ import {
   isReadableStream,
   isErrorRenderResult,
   getRequestBundleFilePath,
+  type RequestInfo,
   validateBundlesExist,
 } from '../shared/utils.js';
 import { getConfig } from '../shared/configBuilder.js';
@@ -46,7 +47,11 @@ async function prepareResult(
       const error = new Error(
         'INVALID NIL or NULL result for rendering. Ensure renderingRequest is a valid string and returns a value.',
       );
-      exceptionMessage = formatExceptionMessage(renderingRequest, error, 'INVALID result for prepareResult');
+      exceptionMessage = formatExceptionMessage(
+        { renderingRequest },
+        error,
+        'INVALID result for prepareResult',
+      );
     } else if (isErrorRenderResult(result)) {
       ({ exceptionMessage } = result);
     }
@@ -69,7 +74,11 @@ async function prepareResult(
       data: result,
     };
   } catch (err) {
-    const exceptionMessage = formatExceptionMessage(renderingRequest, err, 'Unknown error calling runInVM');
+    const exceptionMessage = formatExceptionMessage(
+      { renderingRequest },
+      err,
+      'Unknown error calling runInVM',
+    );
     return errorResponseResult(exceptionMessage);
   }
 }
@@ -81,7 +90,7 @@ async function prepareResult(
  * @param assetsToCopy might be null
  */
 async function handleNewBundleProvided(
-  requestContext: string,
+  requestContext: RequestInfo,
   providedNewBundle: ProvidedNewBundle,
   assetsToCopy: Asset[] | null | undefined,
 ): Promise<ResponseResult | undefined> {
@@ -158,7 +167,7 @@ to ${bundleFilePathPerTimestamp})`,
 }
 
 export async function handleNewBundlesProvided(
-  requestContext: string,
+  requestContext: RequestInfo,
   providedNewBundles: ProvidedNewBundle[],
   assetsToCopy: Asset[] | null | undefined,
 ): Promise<ResponseResult | undefined> {
@@ -241,7 +250,7 @@ export async function handleRenderRequest({
 
     // If gem has posted updated bundle:
     if (providedNewBundles && providedNewBundles.length > 0) {
-      const result = await handleNewBundlesProvided(renderingRequest, providedNewBundles, assetsToCopy);
+      const result = await handleNewBundlesProvided({ renderingRequest }, providedNewBundles, assetsToCopy);
       if (result) {
         return { response: result };
       }
@@ -267,7 +276,7 @@ export async function handleRenderRequest({
     };
   } catch (error) {
     const msg = formatExceptionMessage(
-      renderingRequest,
+      { renderingRequest },
       error,
       'Caught top level error in handleRenderRequest',
     );