Don't start a second sync while syncing is already in progress

Reader/FervorController.swift

@@ -26,7 +26,7 @@ class FervorController {
     
     private(set) var persistentContainer: PersistentContainer!
     
-    let syncStateSubject = PassthroughSubject<SyncState, Never>()
+    @Published private(set) var syncState = SyncState.done
     
     init(instanceURL: URL) {
         self.instanceURL = instanceURL
@@ -47,7 +47,7 @@ class FervorController {
     
     private func setSyncState(_ state: SyncState) {
         DispatchQueue.main.async {
-            self.syncStateSubject.send(state)
+            self.syncState = state
         }
     }
     
@@ -65,6 +65,12 @@ class FervorController {
     }
     
     func syncAll() async throws {
+        guard syncState == .done else {
+            return
+        }
+        // always return to .done, even if we throw and stop syncing early
+        defer { setSyncState(.done) }
+        
         setSyncState(.groupsAndFeeds)
         
         logger.info("Syncing groups and feeds")
@@ -82,8 +88,6 @@ class FervorController {
         
         setSyncState(.excerpts)
         await ExcerptGenerator.generateAll(self)
-        
-        setSyncState(.done)
     }
     
     @MainActor

Reader/Screens/Home/HomeViewController.swift

@@ -93,7 +93,7 @@ class HomeViewController: UIViewController {
         feedResultsController.delegate = self
         try! feedResultsController.performFetch()
         
-        fervorController.syncStateSubject
+        fervorController.$syncState
             .debounce(for: .milliseconds(250), scheduler: RunLoop.main, options: nil)
             .sink { [unowned self] in
                 self.syncStateChanged($0)