Thanos v0.42.0

This maintenance release focuses on hardening the reliability of Thanos core components, specifically targeting the Store Proxy and Receive services. It addresses several critical resource management bugs and improves error reporting to ensure platform engineers have a more predictable experience when managing large-scale metric data.

Error reporting for empty store sets in Store Proxy — This prevents operations from proceeding in a silent failure state when no stores are available, ensuring that SREs receive immediate feedback on misconfigurations or connectivity issues instead of incomplete results.

Stability and resource management fixes for Thanos Receive — This addresses several edge cases in the Receive component, including resource lifetime management and locking issues, leading to better stability for users relying on the push-based ingestion path.

Resolved read lock leak in Store label value lookups — Properly releasing the read lock for label values ensures that the Store component remains responsive and avoids potential deadlocks or performance degradation during metadata lookups.