🚀 [cloud_firestore] Expression type not yet implemented: string_index_of

[sfgbs]

The search pipeline fails on Android with Expression type not yet implemented: string_index_of but on web it works. It comes down to differences between the Web SDK and Native Android Firebase SDK (cloud_firestore 6.7.1):

Technical Cause for Platform Discrepancy:

1. Web SDK (cloud_firestore_web):
   • The JS/Web SDK sends search requests using REST / WebChannel JSON endpoints.
   • On Web, search pipeline stages or tokenized search queries are either routed to specialized search REST endpoints or handled with client-side fallback logic, avoiding the
   unsupported backend gRPC filter AST evaluation.
2. Android Native SDK (cloud_firestore on Android):
   • The Flutter cloud_firestore 6.7.1 package wraps the native Android Firebase SDK (com.google.firebase:firebase-firestore).
   • The native Android SDK translates search/filter pipeline expressions into gRPC protobuf filter AST nodes before transmitting them to Cloud Firestore.
   • When the Cloud Firestore backend receives these gRPC protobuf AST nodes for subcollection search queries, it attempts to map them to backend string matching expressions
   (string_index_of).
   • Because string_index_of expression evaluation is unimplemented in Cloud Firestore's backend gRPC filter engine, the call fails on Android with Expression type not yet implemented:
   string_index_of.

I need the string_index_of expression on web as well on android and ios. Is there already a roadmap for this feature on cloud_firstore?

[SelaseKay]

Hi @sfgbs, thanks for the report. I'll create a PR for this soon.

[sfgbs]

Hi @SelaseKay, great to see you've already implemented it! Thank you very much for your efforts.