2 files changed, 63 insertions, 0 deletions
diff --git a/packages/backend/src/misc/render-full-error.ts b/packages/backend/src/misc/render-full-error.ts
new file mode 100644
index 0000000000..5f0a09bba9
--- /dev/null
+++ b/packages/backend/src/misc/render-full-error.ts
@@ -0,0 +1,60 @@
+/*
+ * SPDX-FileCopyrightText: hazelnoot and other Sharkey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import * as Bull from 'bullmq';
+import { AbortError, FetchError } from 'node-fetch';
+import { StatusError } from '@/misc/status-error.js';
+import { IdentifiableError } from '@/misc/identifiable-error.js';
+import { renderInlineError } from '@/misc/render-inline-error.js';
+import { CaptchaError, captchaErrorCodes } from '@/core/CaptchaService.js';
+
+export function renderFullError(e?: unknown): unknown {
+	if (e === undefined) return 'undefined';
+	if (e === null) return 'null';
+
+	if (e instanceof Error) {
+		if (isSimpleError(e)) {
+			return renderInlineError(e);
+		}
+
+		const data: ErrorData = {};
+		if (e.stack) data.stack = e.stack;
+		if (e.message) data.message = e.message;
+		if (e.name) data.name = e.name;
+
+		// mix "cause" and "errors"
+		if (e instanceof AggregateError && e.errors.length > 0) {
+			const causes = e.errors.map(inner => renderFullError(inner));
+			if (e.cause) {
+				causes.push(renderFullError(e.cause));
+			}
+			data.cause = causes;
+		} else if (e.cause) {
+			data.cause = renderFullError(e.cause);
+		}
+
+		return data;
+	}
+
+	return e;
+}
+
+function isSimpleError(e: Error): boolean {
+	if (e instanceof Bull.UnrecoverableError) return true;
+	if (e instanceof AbortError || e.name === 'AbortError') return true;
+	if (e instanceof FetchError || e.name === 'FetchError') return true;
+	if (e instanceof StatusError) return true;
+	if (e instanceof IdentifiableError) return true;
+	if (e instanceof FetchError) return true;
+	if (e instanceof CaptchaError && e.code !== captchaErrorCodes.unknown) return true;
+	return false;
+}
+
+interface ErrorData {
+	stack?: Error['stack'];
+	message?: Error['message'];
+	name?: Error['name'];
+	cause?: Error['cause'] | Error['cause'][];
+}
diff --git a/packages/backend/src/misc/render-inline-error.ts b/packages/backend/src/misc/render-inline-error.ts
index ccd4f524bc..07f9f3068e 100644
--- a/packages/backend/src/misc/render-inline-error.ts
+++ b/packages/backend/src/misc/render-inline-error.ts
@@ -34,6 +34,9 @@ function renderTo(err: unknown, parts: string[]): void {
 }
 
 function printError(err: unknown): string {
+	if (err === undefined) return 'undefined';
+	if (err === null) return 'null';
+
 	if (err instanceof IdentifiableError) {
 		if (err.message) {
 			return `${err.name} ${err.id}: ${err.message}`;