Merge pull request #412 from wordpress-mobile/fix/wpmediapickerviewcontroller-nsinternalinconsistencyexception-crash

Avoid `WPMediaPickerViewController` `performBatchUpdates` crash by wrapping the call in try-catch block

Author: staskus

CHANGELOG.md

@@ -48,6 +48,12 @@ _None._
 
 _None._
 
+## 1.8.9
+
+### Bug Fixes
+
+- Fix WPMediaPickerViewController crash when performing batch updates [#412]
+
 ## 1.8.8
 
 ### Bug Fixes

Example/Podfile.lock

@@ -1,5 +1,5 @@
 PODS:
-  - WPMediaPicker (1.8.8)
+  - WPMediaPicker (1.8.9-beta.1)
 
 DEPENDENCIES:
   - WPMediaPicker (from `../`)
@@ -9,7 +9,7 @@ EXTERNAL SOURCES:
     :path: "../"
 
 SPEC CHECKSUMS:
-  WPMediaPicker: 0d40b8d66b6dfdaa2d6a41e3be51249ff5898775
+  WPMediaPicker: 0ef7f4abcbff7ad20e271e7d09586e32924f5785
 
 PODFILE CHECKSUM: 31590cb12765a73c9da27d6ea5b8b127c095d71d
 

Pod/Classes/WPMediaPickerViewController.m

@@ -134,7 +134,24 @@ - (void)registerDataSourceObservers {
                                     return;
                                 }
                                 if (incrementalChanges) {
-                                    [weakSelf updateDataWithRemoved:removed inserted:inserted changed:changed moved:moves];
+                                    /// Avoid NSInternalInconsistencyException crash by wrapping performBatchUpdates in the try catch block.
+                                    ///
+                                    /// Apple documentation indicates if the collection view’s layout isn’t up to date before you call performBatchUpdates,
+                                    /// additional reload may occur that can cause problems. Developers should update the data model inside the updates
+                                    /// block or ensure the layout is updated before calling performBatchUpdates.
+                                    /// However, MediaLibraryPickerDataSource reloads the data source before view controller gets informed about updates,
+                                    /// creating a possibility for a crash.
+                                    /// https://developer.apple.com/documentation/uikit/uicollectionview/1618045-performbatchupdates
+                                    ///
+                                    /// Apple engineers reiterate this fact and point out the best way to avoid this issue is to adopt
+                                    /// UICollectionViewDiffableDataSource which requires refactoring of the current solution
+                                    /// https://developer.apple.com/forums/thread/728797?answerId=751887022#751887022
+                                    
+                                    @try {
+                                        [weakSelf updateDataWithRemoved:removed inserted:inserted changed:changed moved:moves];
+                                    } @catch (NSException *exception) {
+                                        [weakSelf.collectionView reloadData];
+                                    }
                                 } else {
                                     [weakSelf.collectionView reloadData];
                                 }

WPMediaPicker.podspec

@@ -2,7 +2,7 @@
 
 Pod::Spec.new do |s|
   s.name          = 'WPMediaPicker'
-  s.version       = '1.8.8'
+  s.version       = '1.8.9-beta.1'
 
   s.summary       = 'WPMediaPicker is an iOS controller that allows capture and picking of media assets.'
   s.description   = <<-DESC