[chain-pr 5/10] DatadogLogs: typed-bus migration

[maxep]

This PR is part of a chain split from maxep/message-bus-subscription by chain-pr.

What and why?

With CoreMessageBus implementing the typed MessageBus protocol (PR #2929), DatadogLogs can retire its FeatureMessageReceiver switch and adopt the typed bus throughout.

LogMessageReceiver and WebViewLogReceiver previously implemented FeatureMessageReceiver with a runtime guard on the .payload case and a cast to the expected type. They now conform to BusMessageReceiver directly, receiving their concrete message type with no envelope or cast.

RemoteLogger previously called featureScope.send(message: .payload(RUMErrorMessage(...))) to forward log errors to RUM. It now holds a MessageBus reference and calls messageBus.send(message:) directly, severing the dependency on FeatureScope for cross-feature emission.

The LogEventAttributes broadcast triggered by Logs.updateGlobalAttribute / Logs.removeGlobalAttribute also moves from core.send(message: .payload(...)) to core.messageBus.send(message:).

How?

MessageReceivers.swift — BusMessageReceiver conformance

Both receivers change from struct to final class (required by BusMessageReceiver) and replace the receive(message: FeatureMessage, from:) -> Bool method with a typed variant:

Receiver	Old	New
LogMessageReceiver	FeatureMessageReceiver — guards on .payload(log as LogMessage)	BusMessageReceiver<LogMessage> — receives LogMessage directly
WebViewLogReceiver	FeatureMessageReceiver — guards on .webview(.log(event))	BusMessageReceiver<WebViewLogMessage> — receives WebViewLogMessage directly

LogsFeature.swift — retained receiver references and subscription wiring

LogsFeature now holds strong references to the two receivers so that Logs.enable can subscribe them after feature creation:

// In Logs.enable:
core.messageBus.subscribe(receiver: feature.logMessageReceiver)
core.messageBus.subscribe(receiver: feature.webViewLogReceiver)

The old CombinedFeatureMessageReceiver wiring in the DatadogRemoteFeature initialiser is replaced with NOPFeatureMessageReceiver().

RemoteLogger.swift — direct bus send for RUM error forwarding

// Before
self.featureScope.send(message: .payload(RUMErrorMessage(...)))

// After
self.messageBus.send(message: RUMErrorMessage(...))

RemoteLogger now receives a MessageBus at init and stores it as let messageBus: MessageBus. The featureScope reference is no longer used for cross-feature emission.

Review checklist

• Feature or bugfix MUST have appropriate tests (unit, integration)
• Make sure each commit and the PR mention the Issue number or JIRA reference
• Add CHANGELOG entry for user facing changes
• Add Objective-C interface for public APIs - see our guidelines (internal)
• Run make api-surface when adding new APIs

---

Chain overview

#	PR	Title
1	#2927	Typed MessageBus protocol and shared message types
2	#2928	Test infrastructure for typed message bus
3	#2929	DatadogCore: CoreMessageBus implementation and rename
4	#2930	DatadogCrashReporting: typed-bus migration
5	← this PR	DatadogLogs: typed-bus migration
6	#2932	DatadogTrace: typed-bus migration
7	#2933	DatadogFlags: typed-bus migration
8	#2934	DatadogRUM: typed-bus migration and TelemetryInterceptor merge
9	#2935	DatadogSessionReplay and DatadogWebViewTracking: typed-bus migration
10	#2936	Documentation updates

graph LR
    G1["1 — Typed MessageBus protocol and shared message types"]
    G2["2 — Test infrastructure for typed message bus"]
    G3["3 — DatadogCore: CoreMessageBus implementation and rename"]
    G4["4 — DatadogCrashReporting: typed-bus migration"]
    G5["5 — DatadogLogs: typed-bus migration"]
    G6["6 — DatadogTrace: typed-bus migration"]
    G7["7 — DatadogFlags: typed-bus migration"]
    G8["8 — DatadogRUM: typed-bus migration and TelemetryInterceptor merge"]
    G9["9 — DatadogSessionReplay and DatadogWebViewTracking: typed-bus migration"]
    G10["10 — Documentation updates"]
    G1 --> G2
    G2 --> G3
    G3 --> G4
    G3 --> G5
    G5 --> G6
    G3 --> G7
    G6 --> G8
    G7 --> G8
    G8 --> G9
    G1 --> G10

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Merge in dependency order. PRs with no incoming edges from un-merged PRs can be reviewed in parallel.

[chatgpt-codex-connector]

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[arroz]

Looks good! Left a comment regarding memory handling, feel free to dismiss if it's safe.

[chatgpt-codex-connector]

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Reviewed commit: 8f8da76055

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[chatgpt-codex-connector]

Avoid accumulating log receivers on re-enable

When Logs.enable(in:) is called more than once for the same core, each call creates a new LogMessageReceiver instance and subscribes it here. The typed bus de-duplicates only the same object identity, whereas the old legacy receiver was replaced under the single "logging" feature key, so subsequent TracingWithLoggingIntegration / span.log LogMessages are delivered to every accumulated receiver and written multiple times.

Useful? React with 👍 / 👎.