Error when importing a file with file containing only excluded saved objects

[ymao1]

With the recently added ability to filter out items onExport, it is possible to export an ndjson file that only contains "excluded" saved objects. If that file is then imported, the following error occurs:

Unhandled Promise rejection detected:

TypeError: Cannot destructure property 'title' of 'obj.attributes' as it is undefined.
    at /Users/ymao/Code/kibana/src/core/server/saved_objects/import/lib/collect_saved_objects.ts:47:15
    at Transform.transform [as _transform] (/Users/ymao/Code/kibana/node_modules/packages/kbn-utils/src/streams/filter_stream.ts:15:33)
    at Transform._read (internal/streams/transform.js:205:10)
    at Transform._write (internal/streams/transform.js:193:12)
    at writeOrBuffer (internal/streams/writable.js:358:12)
    at Transform.Writable.write (internal/streams/writable.js:303:10)
    at Transform.ondata (internal/streams/readable.js:745:22)
    at Transform.emit (events.js:376:20)
    at addChunk (internal/streams/readable.js:309:12)
    at readableAddChunk (internal/streams/readable.js:284:9)
    at Transform.Readable.push (internal/streams/readable.js:223:10)
    at Transform.push (internal/streams/transform.js:166:32)
    at Transform.done (internal/streams/transform.js:101:10)
    at Transform.transform [as _transform] (/Users/ymao/Code/kibana/src/core/server/saved_objects/import/lib/create_limit_stream.ts:21:7)
    at Transform._read (internal/streams/transform.js:205:10)
    at Transform._write (internal/streams/transform.js:193:12)

and the UI shows the following:

In this case, my ndjson contained a single line:

{"excludedObjects":[{"id":"2a16ac09-d834-11eb-b614-2b1b222c1719","reason":"excluded","type":"alert"}],"excludedObjectsCount":1,"exportedCount":0,"missingRefCount":0,"missingReferences":[]}

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)

[ymao1]

It is erroring here:

kibana/src/core/server/saved_objects/import/lib/collect_saved_objects.ts

Lines 39 to 66 in 82e32fa

	const collectedObjects: Array<SavedObject<{ title?: string }>> = await createPromiseFromStreams([
	readStream,
	createLimitStream(objectLimit),
	createFilterStream<SavedObject<{ title: string }>>((obj) => {
	entries.push({ type: obj.type, id: obj.id });
	if (supportedTypes.includes(obj.type)) {
	return true;
	}
	const { title } = obj.attributes;
	errors.push({
	id: obj.id,
	type: obj.type,
	title,
	meta: { title },
	error: {
	type: 'unsupported_type',
	},
	});
	return false;
	}),
	createFilterStream<SavedObject>((obj) => (filter ? filter(obj) : true)),
	createMapStream((obj: SavedObject) => {
	importIdMap.set(`${obj.type}:${obj.id}`, {});
	// Ensure migrations execute on every saved object
	return Object.assign({ migrationVersion: {} }, obj);
	}),
	createConcatStream([]),
	]);

because it can't destructure title from obj.attributes on line 47.

If I add

createFilterStream<SavedObject>((obj) => !!obj.id),

to line 42 to filter out entries without an id, I end up with a "successful" import and this in the UI:

If that's ok for a short term fix, I will add it to my PR

cc @pgayvallet

[pgayvallet]

kibana/src/core/server/saved_objects/routes/utils.ts

Lines 34 to 36 in fd1d965

	createFilterStream<SavedObject | SavedObjectsExportResultDetails>(
	(obj) => !!obj && !(obj as SavedObjectsExportResultDetails).exportedCount
	),

This condition is buggy when exportCount is 0, causing the export detail line to be considered as a SO line.

It should be replaced by

(obj) => !!obj && (obj as SavedObjectsExportResultDetails).exportedCount === undefined

[TinaHeiligers]

@pgayvallet I used your recommendation in #103573 but before realizing you folks had come to a resolution already. I'll close that draft if the fix is in another PR.

[ymao1]

Fix included in this PR: #102999 in these commits:

• 4a8fc64
• f69be9d

Thanks @pgayvallet and @TinaHeiligers for figuring out the bug fix & writing the test and letting me include it in my PR <3