State corruption of selectedOption in MultiSchemaField when editing data within an oneOf

[erunion]

Prerequisites

• I have read the documentation;
• In the case of a bug report, I understand that providing a SSCCE example is tremendously useful to the maintainers.
• Ideally, I'm providing a sample JSFiddle or a shared playground link demonstrating the issue.

Description

On a oneOf schema that contains a handful of objects that might slightly differ, the selectedOption state is immediately corrupted and the selected option changes once editing data within the form.

Debugging, the problem is the componentDidUpdate React event handler on the MultiSchemaField component. This event is invoked anytime formData is changed within the multi schema, and is changing the selectedOption without the users permission, resulting in an incredibly degraded experience on these types of schemas. Check out this playground example for an example of it in action.

Completely eliminating the componentDidUpdate event from this component resolves the issue, but I'm having a hard time understanding why this component has a componentDidUpdate at all to reset the selectedOption when formData changes. selectedOption should only change with the onOptionChange event handler, no?

Steps to Reproduce

1. Load the playground example.
2. Type 1 into the listing_id input.

Expected behavior

The selected MultiSchemaField should not change unless the user invokes a change to the dropdown.

Actual behavior

MultiSchemaField selectedOption state is changed when formData is updated.

Version

This is happening on the latest master.

[skyboyer]

to emphasize: it happens only if formData matches multiple types from same oneOf simultaneously

why it can re-calculate type after formData has changed? Since formData is coming from outside, it's technically possible new data does not match shape of previously selected "oneOf". Maybe a desired result would be not picking first matching type but checking, if data still fits type currently selected. And then picking first matching only if data shape does not satisfy type currently selected.

[skyboyer]

By now, in general case, I see 2 different approaches with their own pitfalls:

1. to convert flat list of "oneOf" into a tree of nested "oneOf" where at each level there would have be unique set of fields. Easier to say than to do, sure.
2. to materialize type with introducing extra field with "enum" of only one possible value("enum": ["Cuba"]), enforce that value with "default": ["Cuba"] and hide it with "ui:widget": "hidden" in UI schema(example). Unfortunately, in this case we need also trim that extra field before sending to server.