Firestore query modifiers - inequality operator with orderBy

[JiriHoffmann]

Hi there! After building out the withCoverter functionality in this PR (#8744), we've successfully migrated our app from JS SDK to react-native-firebase. With that said, we ran into issues with queries that contained an inequality operator != with the combination of orderBy on a different field.

Here is an example of what the query could look like from the query builder:

This query works fine in the query builder and with the JS SDK, but in react-native-firebase it fails due to this check:

react-native-firebase/packages/firestore/lib/FirestoreQueryModifiers.js

Lines 401 to 409 in 72bbef6

	if (INEQUALITY[filter.operator]) {
	// Initial orderBy() parameter has to match every where() fieldPath parameter when inequality operator is invoked
	if (filterFieldPath !== this._orders[0].fieldPath._toPath()) {
	throw new Error(
	`Invalid query. Initial Query.orderBy() parameter: ${orderFieldPath} has to be the same as the Query.where() fieldPath parameter(s): ${filterFieldPath} when an inequality operator is invoked `,
	);
	}
	}

Simply commenting out said check performs the query without any issues. Is it possible this used to be a Firestore limitation that is no longer present? I was trying to search the JS SDK documentation, but with no luck. Any suggestions on how to double-check?

I can also create a PR to remove the limitation

[mikehardy]

Indeed there were 2 relevant issues, with excellent details, that I have just reopened (they erroneously went out stale while I was mostly away during summer...)

cross-linking

• [🐛] Cannot execute query with inequality operator and orderBy different field #8534
• [🐛] 🔥 Query validation may be overly restrictive for inequality filters #8161

There were a class of restrictions in query operator combinations that firestore used to have but eliminated over time, and our old checks for those restrictions are now obsolete. Some have already been removed but I'm not surprised some still exist...

I'm not sure if there is still any mandatory validation we need to do based on current restrictions + current firestore documentation, but a PR to either purge that validation phase out or reduce it to whatever the current set of restrictions is would be most welcome