Fix retain cycle in LiveViewCoordinator (#1455)

* Fix retain cycle in LiveViewCoordinator

`LiveViewCoordinator` is initialised from `LiveSessionCoordinator`, which
gets passed in as a parameter to `init` and then retained by the view
coordinator. This causes a retain cycle.

Additionally, this is also retained by the `handleEvent` as `session`
was used directly in the closure, which then retained it.

This commit fixes both by using a weak reference from the view coordinator
to the session coordinator, and accessing the session via the weak `self`
reference.

* Follow-up robustness fix to avoid rare runtime crash

* Follow-up robustness fix, removing `unowned self`

* Update Sources/LiveViewNative/Coordinators/LiveViewCoordinator.swift

Co-authored-by: Carson Katri <[email protected]>
Signed-off-by: Adrian Schönig <[email protected]>

* Update CHANGELOG.md

---------

Signed-off-by: Adrian Schönig <[email protected]>
Co-authored-by: Carson Katri <[email protected]>

Author: nighthawk

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Form elements will apply updates from a diff (#1451)
 - Updates to change-tracked properties no longer occur on the next RunLoop, fixing modal dismissal on macOS (#1450)
 - `+` characters are properly encoded as `%2B` in form events (#1449)
+- Fixed retain cycle in `LiveViewCoordinator` (#1455)
 
 ## [0.3.0] 2024-08-21
 

Sources/LiveViewNative/Coordinators/LiveSessionCoordinator.swift

@@ -421,9 +421,12 @@ public class LiveSessionCoordinator<R: RootRegistry>: ObservableObject {
             var wsEndpoint = URLComponents(url: self.url, resolvingAgainstBaseURL: true)!
             wsEndpoint.scheme = self.url.scheme == "https" ? "wss" : "ws"
             wsEndpoint.path = "/live/websocket"
+            let configuration = self.urlSession.configuration
             let socket = Socket(
                 endPoint: wsEndpoint.string!,
-                transport: { [unowned self] in URLSessionTransport(url: $0, configuration: self.urlSession.configuration) },
+                transport: {
+                    URLSessionTransport(url: $0, configuration: configuration)
+                },
                 paramsClosure: {
                     [
                         "_csrf_token": domValues.phxCSRFToken,
@@ -505,12 +508,12 @@ public class LiveSessionCoordinator<R: RootRegistry>: ObservableObject {
         }.receive("error") { msg in
             logger.debug("[LiveReload] error connecting to channel: \(msg.payload)")
         }
-        self.liveReloadChannel!.on("assets_change") { [unowned self] _ in
+        self.liveReloadChannel!.on("assets_change") { [weak self] _ in
             logger.debug("[LiveReload] assets changed, reloading")
             Task {
                 StylesheetCache.removeAll()
                 // need to fully reconnect (rather than just re-join channel) because the elixir code reloader only triggers on http reqs
-                await self.reconnect()
+                await self?.reconnect()
             }
         }
     }

Sources/LiveViewNative/Coordinators/LiveViewCoordinator.swift

@@ -32,7 +32,7 @@ public class LiveViewCoordinator<R: RootRegistry>: ObservableObject {
         internalState
     }
 
-    @_spi(LiveForm) public let session: LiveSessionCoordinator<R>
+    @_spi(LiveForm) public private(set) weak var session: LiveSessionCoordinator<R>!
     var url: URL
 
     private var channel: Channel?
@@ -67,10 +67,11 @@ public class LiveViewCoordinator<R: RootRegistry>: ObservableObject {
 
         self.handleEvent("native_redirect") { [weak self] payload in
             guard let self,
-                  let redirect = LiveRedirect(from: payload, relativeTo: self.url)
+                  let redirect = LiveRedirect(from: payload, relativeTo: self.url),
+                  let session = self.session
             else { return }
-            Task { [weak session] in
-                try await session?.redirect(redirect)
+            Task {
+                try await session.redirect(redirect)
             }
         }
     }