[AI-generated] Fix unhandled rejection when disposing invalid input (#413)

* Fix input dispose rejection handling

* Move input disposal regression test

src/input.ts

@@ -527,8 +527,12 @@ export class Input<S extends Source = Source> extends EventEmitter<InputEvents>
 		}
 		this._sourceRefs.length = 0;
 
-		void this._demuxerPromise
-			?.then(demuxer => demuxer.dispose());
+		if (this._demuxerPromise) {
+			// The demuxer promise may already be rejected after failed format detection.
+			void this._demuxerPromise
+				.then(demuxer => demuxer.dispose())
+				.catch(() => {});
+		}
 	}
 
 	/**

test/node/input.test.ts

@@ -0,0 +1,28 @@
+import { expect, test } from 'vitest';
+import { Input, UnsupportedInputFormatError } from '../../src/input.js';
+import { ALL_FORMATS } from '../../src/input-format.js';
+import { BufferSource } from '../../src/source.js';
+
+test('Disposing after failed format detection does not emit an unhandled rejection', async () => {
+	const input = new Input({
+		source: new BufferSource(new Uint8Array([1, 2, 3, 4])),
+		formats: ALL_FORMATS,
+	});
+
+	await expect(input.getFormat()).rejects.toThrow(UnsupportedInputFormatError);
+
+	const unhandledRejections: unknown[] = [];
+	const onUnhandledRejection = (reason: unknown) => {
+		unhandledRejections.push(reason);
+	};
+
+	process.on('unhandledRejection', onUnhandledRejection);
+	try {
+		input.dispose();
+		await new Promise(resolve => setTimeout(resolve, 0));
+	} finally {
+		process.off('unhandledRejection', onUnhandledRejection);
+	}
+
+	expect(unhandledRejections).toEqual([]);
+});