Add AsyncSequence support for Realtime Database #15596
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This change introduces Swift AsyncSequence support for Firebase Realtime Database, enabling a modern, structured concurrency approach for observing data. Key changes include: - `DatabaseQuery.snapshots`: An asynchronous sequence for value events, consistent with Firestore's `snapshots` and Android's RTDB `snapshots()`. - `DatabaseQuery.childEvents()`: An asynchronous sequence for child events (`childAdded`, `childChanged`, `childRemoved`, `childMoved`), consistent with Android's RTDB `childEvents()`. - Implementation uses the `AsyncIteratorProtocol` pattern, aligning with the Firestore SDK for `Sendable` compliance and lazy listener initialization. - `DatabaseQuery` is marked `@retroactive @unchecked Sendable` to resolve concurrency warnings. - The `handles` array in `DatabaseChildEventsSequence.Iterator.init` is explicitly captured by value in `onTermination` to prevent concurrency issues. - Added usage tests to `DatabaseAPITests.swift`. - Refactored Sendable conformances to be grouped together for better readability.
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ncooke3
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laike9m
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laike9m
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This is a great addition to the Realtime Database SDK, providing a modern Swift Concurrency interface for observing data changes. The implementation follows the established patterns in the Firebase Apple SDKs.
I have one minor suggestion regarding Sendable conformance for the DatabaseEvent enum.
| // MARK: - DatabaseEvent | ||
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| /// An enumeration of granular child-level events. | ||
| public enum DatabaseEvent { |
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The DatabaseEvent enum should explicitly conform to Sendable. Since it is a public enum used as the element type of an AsyncSequence, explicit conformance ensures it can be safely used across concurrency boundaries in strict mode. Note that DataSnapshot is already marked NS_SWIFT_SENDABLE in its header, so the enum will satisfy the requirements.
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Good suggestion.
Interesting: given the symbol, DataSnapshot, in a Swift context, it recognized that the symbol was being bridged from Objective-C and the source-of-truth definition was marked sendable.
FirebaseDatabase/Sources/Public/FirebaseDatabase/FIRDataSnapshot.h- */
FirebaseDatabase/Sources/Public/FirebaseDatabase/FIRDataSnapshot.h-NS_SWIFT_SENDABLE
FirebaseDatabase/Sources/Public/FirebaseDatabase/FIRDataSnapshot.h:NS_SWIFT_NAME(DataSnapshot)
FirebaseDatabase/Sources/Public/FirebaseDatabase/FIRDataSnapshot.h-@interface FIRDataSnapshot : NSObject
FirebaseDatabase/Sources/Public/FirebaseDatabase/FIRDataSnapshot.h-
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Yes, from the trace the agent did read FIRDataSnapshot.h so it had the context.
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This change introduces Swift AsyncSequence support for Firebase Realtime Database, enabling a modern, structured concurrency approach for observing data.
Key changes include:
DatabaseQuery.snapshots: An asynchronous sequence for value events, consistent with Firestore'ssnapshotsand Android's RTDBsnapshots().DatabaseQuery.childEvents(): An asynchronous sequence for child events (childAdded,childChanged,childRemoved,childMoved), consistent with Android's RTDBchildEvents().AsyncIteratorProtocolpattern, aligning with the Firestore SDK forSendablecompliance and lazy listener initialization.DatabaseQueryis marked@retroactive @unchecked Sendableto resolve concurrency warnings.handlesarray inDatabaseChildEventsSequence.Iterator.initis explicitly captured by value inonTerminationto prevent concurrency issues.DatabaseAPITests.swift.