Reload any Container rows that have change disclosure state since the last rebuild of the Shadow Table. Fixes #3484

iOS/MasterFeed/MasterFeedViewController.swift

@@ -627,6 +627,14 @@ class MasterFeedViewController: UITableViewController, UndoableCommandRunner {
 			}
 		}
 		
+		if let rowChanges = changes.rowChanges {
+			for rowChange in rowChanges {
+				if let reloads = rowChange.reloadIndexPaths, !reloads.isEmpty {
+					tableView.reloadRows(at: reloads, with: .none)
+				}
+			}
+		}
+
 		completion?()
 	}
 	

iOS/MasterFeed/ShadowTableChanges.swift

@@ -25,6 +25,7 @@ struct ShadowTableChanges {
 		var section: Int
 		var deletes: Set<Int>?
 		var inserts: Set<Int>?
+		var reloads: Set<Int>?
 		var moves: Set<ShadowTableChanges.Move>?
 		
 		var isEmpty: Bool {
@@ -41,15 +42,21 @@ struct ShadowTableChanges {
 			return inserts.map { IndexPath(row: $0, section: section) }
 		}
 		
+		var reloadIndexPaths: [IndexPath]? {
+			guard let reloads = reloads else { return nil }
+			return reloads.map { IndexPath(row: $0, section: section) }
+		}
+		
 		var moveIndexPaths: [(IndexPath, IndexPath)]? {
 			guard let moves = moves else { return nil }
 			return moves.map { (IndexPath(row: $0.from, section: section), IndexPath(row: $0.to, section: section)) }
 		}
 		
-		init(section: Int, deletes: Set<Int>?, inserts: Set<Int>?, moves: Set<Move>?) {
+		init(section: Int, deletes: Set<Int>?, inserts: Set<Int>?, reloads: Set<Int>?, moves: Set<Move>?) {
 			self.section = section
 			self.deletes = deletes
 			self.inserts = inserts
+			self.reloads = reloads
 			self.moves = moves
 		}
 		

iOS/SceneCoordinator.swift

@@ -87,8 +87,16 @@ class SceneCoordinator: NSObject, UndoableCommandRunner {
 	private var fetchSerialNumber = 0
 	private let fetchRequestQueue = FetchRequestQueue()
 	
+	// Which Containers are expanded
 	private var expandedTable = Set<ContainerIdentifier>()
+	
+	// Which Containers used to be expanded. Reset by rebuilding the Shadow Table.
+	private var lastExpandedTable = Set<ContainerIdentifier>()
+	
+	// Which Feeds have the Read Articles Filter enabled
 	private var readFilterEnabledTable = [FeedIdentifier: Bool]()
+	
+	// Flattened tree structure for the Sidebar
 	private var shadowTable = [(sectionID: String, feedNodes: [FeedNode])]()
 	
 	private(set) var preSearchTimelineFeed: Feed?
@@ -719,8 +727,11 @@ class SceneCoordinator: NSObject, UndoableCommandRunner {
 		rebuildBackingStores()
 	}
 	
+	/// This is a special function that expects the caller to change the disclosure arrow state outside this function.
+	/// Failure to do so will get the Sidebar into an invalid state.
 	func expand(_ node: Node) {
 		guard let containerID = (node.representedObject as? ContainerIdentifiable)?.containerID else { return }
+		lastExpandedTable.insert(containerID)
 		expand(containerID)
 	}
 	
@@ -742,8 +753,11 @@ class SceneCoordinator: NSObject, UndoableCommandRunner {
 		clearTimelineIfNoLongerAvailable()
 	}
 	
+	/// This is a special function that expects the caller to change the disclosure arrow state outside this function.
+	/// Failure to do so will get the Sidebar into an invalid state.
 	func collapse(_ node: Node) {
 		guard let containerID = (node.representedObject as? ContainerIdentifiable)?.containerID else { return }
+		lastExpandedTable.remove(containerID)
 		collapse(containerID)
 	}
 	
@@ -1548,9 +1562,10 @@ private extension SceneCoordinator {
 			currentFeedIndexPath = indexPathFor(timelineFeed as AnyObject)
 		}
 		
-		// Compute the differences in the shadow table rows
+		// Compute the differences in the shadow table rows and the expanded table entries
 		var changes = [ShadowTableChanges.RowChanges]()
-		
+		let expandedTableDifference = lastExpandedTable.symmetricDifference(expandedTable)
+
 		for (section, newSectionRows) in newShadowTable.enumerated() {
 			var moves = Set<ShadowTableChanges.Move>()
 			var inserts = Set<Int>()
@@ -1576,9 +1591,22 @@ private extension SceneCoordinator {
 				}
 			}
 			
-			changes.append(ShadowTableChanges.RowChanges(section: section, deletes: deletes, inserts: inserts, moves: moves))
+			// We need to reload the difference in expanded rows to get the disclosure arrows correct when programmatically changing their state
+			var reloads = Set<Int>()
+			
+			for (index, newFeedNode) in newSectionRows.feedNodes.enumerated() {
+				if let newFeedNodeContainerID = (newFeedNode.node.representedObject as? Container)?.containerID {
+					if expandedTableDifference.contains(newFeedNodeContainerID) {
+						reloads.insert(index)
+					}
+				}
+			}
+			
+			changes.append(ShadowTableChanges.RowChanges(section: section, deletes: deletes, inserts: inserts, reloads: reloads, moves: moves))
 		}
 
+		lastExpandedTable = expandedTable
+		
 		// Compute the difference in the shadow table sections
 		var moves = Set<ShadowTableChanges.Move>()
 		var inserts = Set<Int>()