mirror of
https://github.com/Instagram/IGListKit
synced 2026-05-20 07:48:32 +00:00
74affe0887
Summary:
I was able to build a unit test that reproduces the issue. We can avoid the crash by simply returning `nil` when accessing a cell while working range events are being vended.
There is definitely something weird going on here though. When debugging `cellForItemAtIndexPath:` I found:
```
(lldb) po indexPath
<NSIndexPath: 0xc000000000000516> {length = 2, path = 5 - 0}
(lldb) po [[self collectionView] numberOfSections]
11
```
So in theory we should be fine, right? But when I continue I get
```
*** Assertion failure in -[UICollectionViewData numberOfItemsBeforeSection:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit_Sim/UIKit-3600.5.2/UICollectionViewData.m:611
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'request for number of items before section 5 when there are only 3 sections in the collection view'
```
There _were_ 3 sections in the UICV before the update, but the data source and structure powering
Closes https://github.com/Instagram/IGListKit/pull/216
Differential Revision: D4204625
Pulled By: rnystrom
fbshipit-source-id: 455ed199dfc115077e4294e2843016a50e179015
93 lines
3.2 KiB
Objective-C
93 lines
3.2 KiB
Objective-C
/**
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* Copyright (c) 2016-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*/
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#import "IGTestDelegateController.h"
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#import "IGTestCell.h"
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#import "IGTestObject.h"
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@implementation IGTestDelegateController
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- (instancetype)init {
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if (self = [super init]) {
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_willDisplayCellIndexes = [NSCountedSet new];
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_didEndDisplayCellIndexes = [NSCountedSet new];
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self.workingRangeDelegate = self;
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}
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return self;
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}
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- (NSInteger)numberOfItems {
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if ([self.item.value isKindOfClass:[NSNumber class]]) {
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return [self.item.value integerValue];
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}
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return 1;
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}
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- (CGSize)sizeForItemAtIndex:(NSInteger)index {
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return CGSizeMake(self.collectionContext.containerSize.width, 10);
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}
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- (UICollectionViewCell *)cellForItemAtIndex:(NSInteger)index {
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IGTestCell *cell = [self.collectionContext dequeueReusableCellOfClass:IGTestCell.class
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forSectionController:self atIndex:index];
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[[cell label] setText:[NSString stringWithFormat:@"%@", self.item.value]];
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[cell setDelegate:self];
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if (self.cellConfigureBlock) {
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self.cellConfigureBlock(self);
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}
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return cell;
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}
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- (void)didUpdateToObject:(id)object {
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_updateCount++;
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_item = object;
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if (self.itemUpdateBlock) {
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self.itemUpdateBlock();
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}
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}
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- (id<IGListDisplayDelegate>)displayDelegate {
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return self;
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}
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- (void)didSelectItemAtIndex:(NSInteger)index {}
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#pragma mark - IGListDisplayDelegate
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- (void)listAdapter:(IGListAdapter *)listAdapter willDisplaySectionController:(IGListSectionController <IGListSectionType> *)sectionController {
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self.willDisplayCount++;
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}
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- (void)listAdapter:(IGListAdapter *)listAdapter didEndDisplayingSectionController:(IGListSectionController <IGListSectionType> *)sectionController {
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self.didEndDisplayCount++;
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}
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- (void)listAdapter:(IGListAdapter *)listAdapter willDisplaySectionController:(IGListSectionController <IGListSectionType> *)sectionController
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cell:(UICollectionViewCell *)cell
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atIndex:(NSInteger)index {
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[self.willDisplayCellIndexes addObject:@(index)];
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}
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- (void)listAdapter:(IGListAdapter *)listAdapter didEndDisplayingSectionController:(IGListSectionController <IGListSectionType> *)sectionController
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cell:(UICollectionViewCell *)cell
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atIndex:(NSInteger)index {
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[self.didEndDisplayCellIndexes addObject:@(index)];
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}
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- (void)listAdapter:(IGListAdapter *)listAdapter didScrollSectionController:(IGListSectionController <IGListSectionType> *)sectionController {}
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#pragma mark - IGListWorkingRangeDelegate
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- (void)listAdapter:(IGListAdapter *)listAdapter sectionControllerWillEnterWorkingRange:(IGListSectionController<IGListSectionType> *)sectionController {
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__unused UICollectionViewCell *cell = [self.collectionContext cellForItemAtIndex:0 sectionController:self];
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}
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- (void)listAdapter:(IGListAdapter *)listAdapter sectionControllerDidExitWorkingRange:(IGListSectionController<IGListSectionType> *)sectionController {}
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@end
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