errors: trim error.cause.stack as well

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/thin-hotels-explode.md

@@ -0,0 +1,5 @@
+---
+'@backstage/errors': patch
+---
+
+Trim `error.cause.stack` in addition to `error.stack` when trimming stack traces from serialized errors.

packages/errors/src/serialization/error.test.ts

@@ -63,6 +63,20 @@ describe('serialization', () => {
     expect(withoutStack2.stack).not.toBeDefined();
   });
 
+  it('serializes stack traces only when allowed with error cause', () => {
+    const before = new CustomError('m');
+    before.cause = new Error('cause');
+    const withStack: any = serializeError(before, { includeStack: true });
+    const withoutStack1: any = serializeError(before, { includeStack: false });
+    const withoutStack2: any = serializeError(before);
+    expect(withStack.stack).toEqual(before.stack);
+    expect(withStack.cause.stack).toEqual(withStack.cause.stack);
+    expect(withoutStack1.stack).not.toBeDefined();
+    expect(withoutStack2.stack).not.toBeDefined();
+    expect(withoutStack1.cause.stack).not.toBeDefined();
+    expect(withoutStack2.cause.stack).not.toBeDefined();
+  });
+
   it('stringifies all supported forms', () => {
     expect(stringifyError({})).toEqual("unknown error '[object Object]'");
     expect(

packages/errors/src/serialization/error.ts

@@ -60,6 +60,14 @@ export function serializeError(
 
   if (!options?.includeStack) {
     delete result.stack;
+
+    if (
+      result.cause &&
+      typeof result.cause === 'object' &&
+      'stack' in result.cause
+    ) {
+      delete result.cause.stack;
+    }
   }
 
   return result;

plugins/catalog-backend/src/tests/integration.test.ts

@@ -442,7 +442,6 @@ describe('Catalog Backend Integration', () => {
                 cause: {
                   name: 'Error',
                   message: 'NOPE',
-                  stack: expect.stringMatching(/^Error: NOPE/),
                 },
               },
             },