Correctly serialize ThrowableDiagnostic from transformers

packages/core/core/src/Transformation.js

@@ -26,9 +26,11 @@ import {Readable} from 'stream';
 import nullthrows from 'nullthrows';
 import logger, {PluginLogger} from '@parcel/logger';
 import ThrowableDiagnostic, {
+  anyToDiagnostic,
   errorToDiagnostic,
   escapeMarkdown,
   md,
+  type Diagnostic,
 } from '@parcel/diagnostic';
 import {SOURCEMAP_EXTENSIONS} from '@parcel/utils';
 import {hashString} from '@parcel/hash';
@@ -84,7 +86,7 @@ export type TransformationOpts = {|
 
 export type TransformationResult = {|
   assets?: Array<AssetValue>,
-  error?: Error,
+  error?: Array<Diagnostic>,
   configRequests: Array<ConfigRequest>,
   invalidations: Array<RequestInvalidation>,
   invalidateOnFileCreate: Array<InternalFileCreateInvalidation>,
@@ -197,7 +199,8 @@ export default class Transformation {
       $$raw: true,
       assets,
       configRequests,
-      error,
+      // When throwing an error, this (de)serialization is done automatically by the WorkerFarm
+      error: error ? anyToDiagnostic(error) : undefined,
       invalidateOnFileCreate: this.invalidateOnFileCreate,
       invalidations: [...this.invalidations.values()],
       devDepRequests,

packages/core/core/src/requests/AssetRequest.js

@@ -13,6 +13,7 @@ import type {ConfigAndCachePath} from './ParcelConfigRequest';
 import type {TransformationResult} from '../Transformation';
 
 import nullthrows from 'nullthrows';
+import ThrowableDiagnostic from '@parcel/diagnostic';
 import {hashString} from '@parcel/hash';
 import createParcelConfigRequest from './ParcelConfigRequest';
 import {runDevDepRequest} from './DevDepRequest';
@@ -175,7 +176,7 @@ async function run({input, api, farm, invalidateReason, options}: RunInput) {
   }
 
   if (error != null) {
-    throw error;
+    throw new ThrowableDiagnostic({diagnostic: error});
   } else {
     return nullthrows(assets);
   }