fix(query): handle casting array filter paths underneath array filter paths with embedded discriminators

[vkarpov15]

Fix #15386

Summary

The issue in #15386 is that events.$[event].products.$[product].price updates don't quite work if products is a path on an embedded discriminator where the discriminator key is set in the event array filter.

To get that to work, we needed to first fix castArrayFilters() to handle this pattern when casting array filters, and then improve how we handle casting the update in castUpdate() (getEmbeddedDiscriminatorPath() changes).

Examples

[Copilot]

Pull Request Overview

This PR fixes an issue with casting array filter paths that reference embedded discriminators, as described in #15386. Key changes include:

• Adding and propagating a discriminator value map in castArrayFilters and getPath.
• Updating getEmbeddedDiscriminatorPath to correctly handle starting indices when processing embedded discriminator paths.
• Adding tests for the new pattern in update.castArrayFilters.test.js.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
test/helpers/update.castArrayFilters.test.js	Added a new test validating proper casting of array filter paths with embedded discriminators.
lib/helpers/update/castArrayFilters.js	Modified to build a discriminator value map and pass it to getPath for embedded discriminator casting.
lib/helpers/schema/getPath.js	Updated the function signature to accept a discriminator value map and use it when traversing the schema.
lib/helpers/query/getEmbeddedDiscriminatorPath.js	Adjusted the path splitting logic by introducing a startIndex to handle multiple embedded discriminators.

Comments suppressed due to low confidence (1)

lib/helpers/query/getEmbeddedDiscriminatorPath.js:32

• [nitpick] Consider renaming 'startIndex' to something like 'discriminatorStartIndex' to more clearly indicate its purpose.

const originalSubpath = parts.slice(startIndex, i + 1).join('.');

[hasezoey]

LGTM, some minor nitpicks.