clean up IGListExperimentFixCrashOnReloadObjects

Summary: Stability metrics look neutral, so lets ship! This was expected since we had a fix on the product side already. The IGListKit fix prevents it from happening in the first place.

Reviewed By: candance

Differential Revision: D52743455

fbshipit-source-id: e92b2a578b993cb228bbe245c3a1a5ac3bdfe5cf

Source/IGListDiffKit/IGListExperiments.h

@@ -22,10 +22,8 @@ typedef NS_OPTIONS (NSInteger, IGListExperiment) {
     IGListExperimentSkipPerformUpdateIfPossible = 1 << 3,
     /// Test skipping creating {view : section controller} map, which has inconsistency issue.
     IGListExperimentSkipViewSectionControllerMap = 1 << 4,
-    /// Use the correct section index when calling -[IGListAdapter reloadObjects ...] within the update block.
-    IGListExperimentFixCrashOnReloadObjects = 1 << 5,
     /// Throw NSInternalInconsistencyException during an update
-    IGListExperimentThrowOnInconsistencyException = 1 << 6
+    IGListExperimentThrowOnInconsistencyException = 1 << 5
 };
 
 /**

Source/IGListKit/IGListAdapter.m

@@ -28,11 +28,6 @@
     CGFloat max;
 } OffsetRange;
 
-@interface IGListAdapter ()
-// Temporary param to key the old behavior during testing
-@property (nonatomic, assign) BOOL legacyIsInDataUpdateBlock;
-@end
-
 @implementation IGListAdapter {
     NSMapTable<UICollectionReusableView *, IGListSectionController *> *_viewSectionControllerMap;
     // An array of blocks to execute once batch updates are finished
@@ -915,12 +910,7 @@ - (void)_exitBatchUpdates {
 }
 
 - (BOOL)isInDataUpdateBlock {
-    if (IGListExperimentEnabled(_experiments, IGListExperimentFixCrashOnReloadObjects)) {
-        // The updater has a better picture of when we're updating the data, including both section and item level changes.
-        return self.updater.isInDataUpdateBlock;
-    } else {
-        return self.legacyIsInDataUpdateBlock;
-    }
+    return self.updater.isInDataUpdateBlock;
 }
 
 #pragma mark - UIScrollViewDelegate
@@ -1293,10 +1283,8 @@ - (void)performBatchAnimated:(BOOL)animated updates:(void (^)(id<IGListBatchCont
     [self _enterBatchUpdates];
     __weak __typeof__(self) weakSelf = self;
     [self.updater performUpdateWithCollectionViewBlock:[self _collectionViewBlock] animated:animated itemUpdates:^{
-        weakSelf.legacyIsInDataUpdateBlock = YES;
         // the adapter acts as the batch context with its API stripped to just the IGListBatchContext protocol
         updates(weakSelf);
-        weakSelf.legacyIsInDataUpdateBlock = NO;
     } completion: ^(BOOL finished) {
         [weakSelf _updateBackgroundView];
         [weakSelf _notifyDidUpdate:IGListAdapterUpdateTypeItemUpdates animated:animated];

Tests/IGListAdapterE2ETests.m

@@ -669,9 +669,6 @@ - (void)test_whenReloadingItems_withPerformUpdates_thatReloadIsApplied {
 }
 
 - (void)test_whenReloadingItems_inItemUpdateBlock_thatDoesntCrash {
-    self.adapter.experiments |= IGListExperimentFixCrashOnReloadObjects;
-    // Without this fix, this test crashes with: Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayI objectAtIndexedSubscript:]: index 2 beyond bounds [0 .. 1]'
-
     [self setupWithObjects:@[
         genTestObject(@1, @1),
         genTestObject(@2, @2),