feat: show all cause in Error (#5422)

* feat: show all cause in Error

* test: sample to test stderr cause

* Add indentation

---------

Co-authored-by: Lukas Taegert-Atkinson <lukastaegert@users.noreply.github.com>
Co-authored-by: Lukas Taegert-Atkinson <lukas.taegert-atkinson@tngtech.com>

cli/logging.ts

@@ -35,6 +35,23 @@ export function handleError(error: RollupError, recover = false): void {
 		outputLines.push(dim(error.stack?.replace(`${nameSection}${error.message}\n`, '')));
 	}
 
+	// ES2022: Error.prototype.cause is optional
+	if (error.cause) {
+		let cause = error.cause as Error | undefined;
+		const causeErrorLines = [];
+		let indent = '';
+
+		while (cause) {
+			indent += '  ';
+			const message = cause.stack || cause;
+			causeErrorLines.push(...`[cause] ${message}`.split('\n').map(line => indent + line));
+
+			cause = cause.cause as Error | undefined;
+		}
+
+		outputLines.push(dim(causeErrorLines.join('\n')));
+	}
+
 	outputLines.push('', '');
 	stderr(outputLines.join('\n'));
 

test/cli/samples/handles-errors-cause/_config.js

@@ -0,0 +1,14 @@
+const { assertIncludes } = require('../../../utils.js');
+
+module.exports = defineTest({
+	description: 'prints error cause',
+	command: 'rollup --config rollup.config.mjs',
+	// We expect an error and want to make assertions about the output
+	error: () => true,
+	stderr: stderr => {
+		// We just assert the parts of the output that do not change
+		assertIncludes(stderr, '\n[!] (plugin at position 1) Error: Outer error\n    at ');
+		assertIncludes(stderr, '\n  [cause] Error: Inner error\n      at ');
+		assertIncludes(stderr, '\n    [cause] Error: Innermost error\n        at ');
+	}
+});

test/cli/samples/handles-errors-cause/main.js

@@ -0,0 +1 @@
+assert.ok(true);

test/cli/samples/handles-errors-cause/rollup.config.mjs

@@ -0,0 +1,14 @@
+export default {
+  input: "main.js",
+  plugins: [
+    {
+      buildStart() {
+        throw new Error("Outer error", {
+          cause: new Error("Inner error", {
+            cause: new Error("Innermost error")
+          })
+        });
+      }
+    }
+  ]
+};