From 0ff1c123aa16d516c486a27ed34236d6ccf5831f Mon Sep 17 00:00:00 2001
From: Doug <6060466+pixlwave@users.noreply.github.com>
Date: Tue, 9 Apr 2024 11:11:14 +0100
Subject: [PATCH] Fix child presentation of the same room. (#2669)

---
 .../RoomFlowCoordinator.swift                 |  4 ++-
 .../Sources/RoomFlowCoordinatorTests.swift    | 32 ++++++++++++++++---
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/ElementX/Sources/FlowCoordinators/RoomFlowCoordinator.swift b/ElementX/Sources/FlowCoordinators/RoomFlowCoordinator.swift
index fee3c4a8b..311128650 100644
--- a/ElementX/Sources/FlowCoordinators/RoomFlowCoordinator.swift
+++ b/ElementX/Sources/FlowCoordinators/RoomFlowCoordinator.swift
@@ -112,8 +112,10 @@ class RoomFlowCoordinator: FlowCoordinatorProtocol {
         case .childRoom(let roomID):
             if case .presentingChild = stateMachine.state, let childRoomFlowCoordinator {
                 childRoomFlowCoordinator.handleAppRoute(appRoute, animated: animated)
-            } else {
+            } else if roomID != roomProxy.id {
                 stateMachine.tryEvent(.presentChildRoom(roomID: roomID), userInfo: EventUserInfo(animated: animated))
+            } else {
+                MXLog.info("Ignoring presentation of the same room as a child of this one.")
             }
         case .roomDetails(let roomID):
             guard roomID == roomProxy.id else { fatalError("Navigation route doesn't belong to this room flow.") }
diff --git a/UnitTests/Sources/RoomFlowCoordinatorTests.swift b/UnitTests/Sources/RoomFlowCoordinatorTests.swift
index 487558f40..afff9847a 100644
--- a/UnitTests/Sources/RoomFlowCoordinatorTests.swift
+++ b/UnitTests/Sources/RoomFlowCoordinatorTests.swift
@@ -80,12 +80,10 @@ class RoomFlowCoordinatorTests: XCTestCase {
         XCTAssertEqual(navigationStackCoordinator.stackCoordinators.count, 0)
         
         try await process(route: .childRoom(roomID: "2"))
-        try await Task.sleep(for: .milliseconds(100))
         XCTAssertEqual(navigationStackCoordinator.stackCoordinators.count, 1)
         XCTAssert(navigationStackCoordinator.stackCoordinators.first is RoomScreenCoordinator)
         
         try await process(route: .childRoom(roomID: "3"))
-        try await Task.sleep(for: .milliseconds(100))
         XCTAssertEqual(navigationStackCoordinator.stackCoordinators.count, 2)
         XCTAssert(navigationStackCoordinator.stackCoordinators.first is RoomScreenCoordinator)
         XCTAssert(navigationStackCoordinator.stackCoordinators.last is RoomScreenCoordinator)
@@ -122,7 +120,6 @@ class RoomFlowCoordinatorTests: XCTestCase {
         XCTAssertEqual(navigationStackCoordinator.stackCoordinators.count, 0)
         
         try await process(route: .childRoom(roomID: "2"))
-        try await Task.sleep(for: .milliseconds(100))
         XCTAssertEqual(navigationStackCoordinator.stackCoordinators.count, 1)
         XCTAssert(navigationStackCoordinator.stackCoordinators.first is RoomScreenCoordinator)
         
@@ -132,11 +129,38 @@ class RoomFlowCoordinatorTests: XCTestCase {
         XCTAssert(navigationStackCoordinator.stackCoordinators.last is RoomMemberDetailsScreenCoordinator)
     }
     
+    func testChildRoomIgnoresDirectDuplicate() async throws {
+        await setupViewModel()
+        
+        try await process(route: .room(roomID: "1"))
+        XCTAssert(navigationStackCoordinator.rootCoordinator is RoomScreenCoordinator)
+        XCTAssertEqual(navigationStackCoordinator.stackCoordinators.count, 0)
+        
+        try await process(route: .childRoom(roomID: "1"))
+        XCTAssertEqual(navigationStackCoordinator.stackCoordinators.count, 0,
+                       "A room flow shouldn't present a direct child for the same room.")
+        
+        try await process(route: .childRoom(roomID: "2"))
+        XCTAssertEqual(navigationStackCoordinator.stackCoordinators.count, 1)
+        XCTAssert(navigationStackCoordinator.stackCoordinators.first is RoomScreenCoordinator)
+        
+        try await process(route: .childRoom(roomID: "1"))
+        XCTAssertEqual(navigationStackCoordinator.stackCoordinators.count, 2,
+                       "Presenting the same room multiple times should be allowed when it's not a direct child of itself.")
+        XCTAssert(navigationStackCoordinator.stackCoordinators.first is RoomScreenCoordinator)
+        XCTAssert(navigationStackCoordinator.stackCoordinators.last is RoomScreenCoordinator)
+    }
+    
     // MARK: - Private
     
     private func process(route: AppRoute) async throws {
         roomFlowCoordinator.handleAppRoute(route, animated: true)
-        await Task.yield()
+        if case .childRoom = route {
+            // A single yield isn't enough when creating the new flow coordinator.
+            try await Task.sleep(for: .milliseconds(100))
+        } else {
+            await Task.yield()
+        }
     }
     
     private func process(route: AppRoute, expectedAction: RoomFlowCoordinatorAction) async throws {