Saved Object Import UI - Multiple modals show up but there is no wait for user input (when input format is JSON)

[lucabelluccini]

Kibana version: 7.8.1, 7.9.0

Elasticsearch version: aligned

Browser version: Version 84.0.4147.135 (Official Build) (64-bit)

Browser OS version: MacOS Mojave 10.14.6 (18G4032)

Describe the bug:

Importing several objects in Saved Objects UI and disabling automatic overwrite.
If there are multiple objects to overwrite, the Kibana UI triggers multiple modals to prompt for cancel or overwrite but they cannot be used.
Only the last one is shown and Kibana keeps waiting for all the modals (no more visible).
This only happens when the data format is JSON (e.g. coming from 6.x)

Steps to reproduce:

1. Install the Sample web logs in a Kibana 6.8
2. Export some of the saved objects
3. Go on a Kibana 7.8.1 or 7.9.0 (or earlier probably affected)
4. Ensure the index patterns IDs used by the visualizations exported in (2) exist on this Kibana (create them forcing the same IDs)
5. Go to Stack management / Saved Objects
6. Import the file, enabling Automatically overwrite all saved objects?
7. Import the file again, disabling Automatically overwrite all saved objects?
8. Multiple prompts will appear, but the disappear immediately except one
9. Answering the last modal will leave Kibana import process waiting

Expected behavior:

Wait for user input when asked to overwrite, as it seems to happen for NDJSON format.

Screenshots (if relevant):

Errors in browser console (if relevant):

409 errors, but I think they're triggered when checking if it exists.

Any additional context:

This can happen when a user wants to replicate a behavior in different environments.

[elasticmachine]

Pinging @elastic/kibana-platform (Team:Platform)

[pgayvallet]

Note that this is only happening when importing in the legacy (json) format. ndjson imports override confirmation popin is behaving correctly.

[pgayvallet]

@lucabelluccini could you share the json export file you used to reproduce this issue?

[pgayvallet]

Seems to be caused by the parallel work we are doing on the indexPattern import

kibana/src/plugins/saved_objects_management/public/lib/resolve_saved_objects.ts

Lines 283 to 290 in de4eaf9

	await awaitEachItemInParallel(docTypes.indexPatterns, async (indexPatternDoc) => {
	try {
	const importedIndexPatternId = await importIndexPattern(
	indexPatternDoc,
	indexPatterns,
	overwriteAll,
	confirmModalPromise
	);

All the conflicting indexPatterns resolutions are executed at the same time, causing all the confirmation modals to be opened at the same time. But as we only allow one modal at a time in

kibana/src/core/public/overlays/modal/modal_service.tsx

Lines 154 to 159 in 395d621

	openConfirm: (message: MountPoint | string, options?: OverlayModalConfirmOptions) => {
	// If there is an active modal, close it before opening a new one.
	if (this.activeModal) {
	this.activeModal.close();
	this.cleanupDom();
	}

All modals but the last are silently closed.

This is still surprising that the associated promises never get to resolve, as opening a modal should resolve the previous modal's promise.

But anyway, removing the awaitEachItemInParallel wrapper around importIndexPattern seems the easiest way to fix this.