From 97894f5d61e5f28f94111f0e7cb358d36ff9e2ca Mon Sep 17 00:00:00 2001
From: James Magahern <jmagahern@apple.com>
Date: Mon, 15 Feb 2021 18:40:15 -0800
Subject: [PATCH] TabView: fix consistency error when closing tabs

---
 App/Tabs/TabBarView.swift | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/App/Tabs/TabBarView.swift b/App/Tabs/TabBarView.swift
index a1d3f14..c08b526 100644
--- a/App/Tabs/TabBarView.swift
+++ b/App/Tabs/TabBarView.swift
@@ -9,7 +9,7 @@ import UIKit
 
 class TabView: UIControl
 {
-    var active: Bool = false { didSet { setNeedsLayout() } }
+    var active: Bool = false { didSet { layoutSubviews() } }
     var collapsed: Bool = false
     var identifier: UUID?
     
@@ -153,7 +153,6 @@ class TabBarView: UIView
             let identifier = dataSource.tabBarView(self, uniqueIdentifierForTabAtIndex: i)
             if let tabView = tabViewsRemoved.first(where: { $0.identifier == identifier }) {
                 tabViewsRemoved.remove(tabView)
-                self.reloadTab(atIndex: i)
             } else {
                 let newTabView = makeTabView(withIdentifier: identifier)
                 if animated { newTabView.collapsed = true }
@@ -170,6 +169,11 @@ class TabBarView: UIView
             // Outgoing tabs collapse
             tabViewsRemoved.forEach { $0.collapsed = true }
             
+            // Reload tabs that are still here
+            for i in 0..<numberOfTabs {
+                reloadTab(atIndex: i)
+            }
+            
             UIView.animate(withDuration: 0.22, delay: 0.0, usingSpringWithDamping: 1.0, initialSpringVelocity: 1.0, options: [], animations: { [unowned self] in
                 layoutSubviews()
             }, completion: { [unowned self] finished in
@@ -189,10 +193,13 @@ class TabBarView: UIView
         
         let title = dataSource.tabBarView(self, titleForTabAtIndex: index)
         let image = dataSource.tabBarView(self, imageForTabAtIndex: index)
+        let identifier = dataSource.tabBarView(self, uniqueIdentifierForTabAtIndex: index)
         
-        let tabView = tabViews[index]
-        tabView.label.text = title
-        tabView.imageView.image = image
+        if let tabView = visibleTab(atIndex: index) {
+            tabView.label.text = title
+            tabView.imageView.image = image
+            tabView.identifier = identifier
+        }
     }
     
     public func activateTab(atIndex index: Int) {
@@ -200,6 +207,13 @@ class TabBarView: UIView
         setNeedsLayout()
     }
     
+    private func visibleTab(atIndex index: Int) -> TabView? {
+        let visibleTabs = tabViews.filter { $0.collapsed == false }
+        if index >= visibleTabs.count { return nil }
+        
+        return visibleTabs[index]
+    }
+    
     private func makeTabView(withIdentifier identifier: UUID) -> TabView {
         let tabView = TabView()
         tabView.identifier = identifier
@@ -253,7 +267,8 @@ class TabBarView: UIView
             tabWidth = maximumTabWidth
         }
         
-        for (i, tabView) in tabViews.enumerated() {
+        var visibleTabIndex = 0
+        for tabView in tabViews {
             tabContainerView.addSubview(tabView)
             
             tabView.alpha = tabView.collapsed ? 0.0 : 1.0
@@ -267,13 +282,15 @@ class TabBarView: UIView
             
             xOffset += tabView.frame.width
             
-            if i == activeTabIndex {
+            if visibleTabIndex == activeTabIndex {
                 tabView.active = true
             } else {
                 tabView.active = false
             }
             
             tabView.layoutIfNeeded()
+            
+            if !tabView.collapsed { visibleTabIndex += 1 }
         }
         
         tabContainerView.contentSize = CGSize(