[Fix]Fast reconnection flow due to ICE misconfiguration #741

ipavlidakis · 2025-04-02T08:11:05Z

📝 Summary

FastReconnection seems to have been broken due to ICE candidates not being applied correctly for the subscriber.

🛠 Implementation

We use this revision as an opportunity to align the fast reconnection process to the latest requirements from the SFU. Namely the changes are:

During fast reconnection, we only restartICE for the publisher connection. That should trigger a negotiation with iceConstraints.
During fast reconnection, when sending the joinRequest we always use temporary connections to generate the SDP rather than using any existing ones.
RestartICE on subscriber connection doesn't invoke the RTCPeerConnection.restartICE method but instead sends the iceRestart RPC call to the SFU. The SFU then will send a new subscriberOffer that will trigger the flow to update the ice state on the subscriber connection.

🧪 Manual Testing Notes

Join a call
Disable wifi for a second and enable it again
You should be connected back and all tracks (local and remote) should be active in a reasonable amount of time
Start screensharing
Disable wifi for a second and enable it again
You should be connected back and all tracks (local and remote) should be active in a reasonable amount of time

☑️ Contributor Checklist

I have signed the Stream CLA (required)
This change follows zero ⚠️ policy (required)
This change should receive manual QA
Changelog is updated with client-facing changes
New code is covered by unit tests
Comparison screenshots added for visual changes
Affected documentation updated (tutorial, CMS)

Stream-SDK-Bot · 2025-04-02T08:18:57Z

SDK Size

`title`	`develop`	`branch`	`status`
StreamVideo	7.6 MB	7.6 MB	🟢
StreamVideoSwiftUI	2.09 MB	2.09 MB	🟢
StreamVideoUIKit	2.23 MB	2.23 MB	🟢
StreamWebRTC	9.85 MB	9.85 MB	🟢

martinmitrevski

Looks good 👍 Let's do some testing today and tomorrow before merging it.

martinmitrevski · 2025-04-02T08:51:23Z

Sources/StreamVideo/Utils/SerialActor/SerialActorQueue.swift

-                    fileName: file,
-                    lineNumber: line
-                )
+                if error is CancellationError { /* No-op */ }


should we maybe add a debug log here that the task was cancelled? Also the formatting looks weird.

That wouldn't be necessary. Cancelled tasks aren't errors but it means that the operation is invalid (most probably because the initiator of the task has e.g. deallocated). For formatting I just using that kind of formatting across the code base as i won't to make the cancellationError skipping as minimal as possible. Happy to expand it in 3 lines if you want to.

I meant a debug log, not an error log

I still don't think it's necessary. This is lowest component for executing the tasks. The only way to get cancelled tasks is to do it explicitely or deallocate the object. In both options the higher level code should log.

Sources/StreamVideo/WebRTC/v2/PeerConnection/Adapters/ICEAdapter.swift

...WebRTC/v2/PeerConnection/MediaAdapters/LocalMediaAdapters/LocalScreenShareMediaAdapter.swift

Sources/StreamVideo/WebRTC/v2/StateMachine/Stages/WebRTCCoordinator+Joining.swift

github-actions · 2025-04-02T10:36:11Z

Public Interface

 public final class SerialActorQueue: Sendable  
-   public func async(file: StaticString = #file,functionName: StaticString = #function,line: UInt = #line,_ block: @Sendable @escaping () async throws -> Void)
+   public func cancelAll()
-   public func sync(_ block: @Sendable @escaping () async throws -> Void)async throws
+   public func async(file: StaticString = #file,functionName: StaticString = #function,line: UInt = #line,_ block: @Sendable @escaping () async throws -> Void)
+   public func sync(_ block: @Sendable @escaping () async throws -> Void)async throws

github-actions · 2025-04-02T10:36:14Z

	1 Warning
⚠️	Big PR

Generated by 🚫 Danger

github-actions · 2025-04-02T10:43:12Z

Public Interface

 public final class SerialActorQueue: Sendable  
-   public func async(file: StaticString = #file,functionName: StaticString = #function,line: UInt = #line,_ block: @Sendable @escaping () async throws -> Void)
+   public func cancelAll()
-   public func sync(_ block: @Sendable @escaping () async throws -> Void)async throws
+   public func async(file: StaticString = #file,functionName: StaticString = #function,line: UInt = #line,_ block: @Sendable @escaping () async throws -> Void)
+   public func sync(_ block: @Sendable @escaping () async throws -> Void)async throws

github-actions · 2025-04-03T14:23:14Z

Public Interface

 public final class SerialActorQueue: Sendable  
-   public func async(file: StaticString = #file,functionName: StaticString = #function,line: UInt = #line,_ block: @Sendable @escaping () async throws -> Void)
+   public func cancelAll()
-   public func sync(_ block: @Sendable @escaping () async throws -> Void)async throws
+   public func async(file: StaticString = #file,functionName: StaticString = #function,line: UInt = #line,_ block: @Sendable @escaping () async throws -> Void)
+   public func sync(_ block: @Sendable @escaping () async throws -> Void)async throws

ipavlidakis · 2025-04-03T14:23:17Z

Sources/StreamVideo/WebRTC/v2/SFU/SFUEventAdapter.swift

-    /// Handles a JoinResponse event.
-    ///
-    /// - Parameter event: The JoinResponse event to handle.
-    private func handleJoinResponse(


We remove the handling from the SFUEventAdapter as the processing of the JoinResponse happens in WebRTCCoordinator+Joining. Having it here causes duplicated processing of the event.

github-actions · 2025-04-03T16:35:32Z

Public Interface

 public final class SerialActorQueue: Sendable  
-   public func async(file: StaticString = #file,functionName: StaticString = #function,line: UInt = #line,_ block: @Sendable @escaping () async throws -> Void)
+   public func cancelAll()
-   public func sync(_ block: @Sendable @escaping () async throws -> Void)async throws
+   public func async(file: StaticString = #file,functionName: StaticString = #function,line: UInt = #line,_ block: @Sendable @escaping () async throws -> Void)
+   public func sync(_ block: @Sendable @escaping () async throws -> Void)async throws

github-actions · 2025-04-04T17:38:56Z

Public Interface

 public final class SerialActorQueue: Sendable  
-   public func async(file: StaticString = #file,functionName: StaticString = #function,line: UInt = #line,_ block: @Sendable @escaping () async throws -> Void)
+   public func cancelAll()
-   public func sync(_ block: @Sendable @escaping () async throws -> Void)async throws
+   public func async(file: StaticString = #file,functionName: StaticString = #function,line: UInt = #line,_ block: @Sendable @escaping () async throws -> Void)
+   public func sync(_ block: @Sendable @escaping () async throws -> Void)async throws

sonarqubecloud · 2025-04-04T17:54:06Z

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
94.9% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

ipavlidakis added bug Something isn't working enhancement New feature or request labels Apr 2, 2025

ipavlidakis self-assigned this Apr 2, 2025

ipavlidakis requested a review from a team as a code owner April 2, 2025 08:11

martinmitrevski reviewed Apr 2, 2025

View reviewed changes

ipavlidakis force-pushed the fix/fast-reconnection branch from b1ffa99 to 17da89a Compare April 2, 2025 10:40

ipavlidakis added 3 commits April 3, 2025 16:34

[Fix]Fast reconnection flow due to ICE misconfiguration

ac2b37f

Update changelog

36e4f84

Remove manual call on draining SFU candidates. Rely on automatic

b463476

martinmitrevski approved these changes Apr 3, 2025

View reviewed changes

Fix duplicated processing of JoinResponse

0aba5f7

ipavlidakis force-pushed the fix/fast-reconnection branch from 17da89a to 0aba5f7 Compare April 3, 2025 14:21

ipavlidakis commented Apr 3, 2025

View reviewed changes

Fix failing test

add2167

Merge branch 'develop' into fix/fast-reconnection

2d30548

ipavlidakis enabled auto-merge (squash) April 7, 2025 10:31

ipavlidakis disabled auto-merge April 7, 2025 10:31

ipavlidakis merged commit 5e4667d into develop Apr 7, 2025
14 checks passed

ipavlidakis deleted the fix/fast-reconnection branch April 7, 2025 10:31

Stream-SDK-Bot mentioned this pull request Apr 7, 2025

1.20.0 Release #749

Merged

[Fix]Fast reconnection flow due to ICE misconfiguration #741

[Fix]Fast reconnection flow due to ICE misconfiguration #741

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ipavlidakis commented Apr 2, 2025

📝 Summary

🛠 Implementation

🧪 Manual Testing Notes

☑️ Contributor Checklist

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github-actions bot commented Apr 2, 2025

Public Interface

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Public Interface

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github-actions bot commented Apr 3, 2025

Public Interface

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github-actions bot commented Apr 3, 2025

Public Interface

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Public Interface

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sonarqubecloud bot commented Apr 4, 2025

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Stream-SDK-Bot commented Apr 2, 2025 •

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