Skip to content
This repository has been archived by the owner on Feb 12, 2022. It is now read-only.

fix scrolling crashes #14

Merged
merged 2 commits into from
Aug 10, 2017
Merged

fix scrolling crashes #14

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
7a7deff
Adjusting insets should invalidate layout
michaelkirk Aug 10, 2017
146b84f
Fix scrolling crash
michaelkirk Aug 10, 2017
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 6 additions & 0 deletions JSQMessagesViewController/Controllers/JSQMessagesViewController.m
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1064,6 +1064,12 @@ - (void)jsq_setCollectionViewInsetsTopValue:(CGFloat)top bottomValue:(CGFloat)bo
UIEdgeInsets insets = UIEdgeInsetsMake(top, 0.0f, bottom, 0.0f);
self.collectionView.contentInset = insets;
self.collectionView.scrollIndicatorInsets = insets;

// BEGIN SIGNAL HACK to fix crash when scrolling while popping or dismissing keyboard
// We should invalidate layout whenever the contentInsets change.
[self.collectionView.collectionViewLayout invalidateLayoutWithContext:[JSQMessagesCollectionViewFlowLayoutInvalidationContext context]];
[self.collectionView.collectionViewLayout invalidateLayout];
// END SIGNAL HACK to fix crash when scrolling while popping or dismissing keyboard
}

- (BOOL)jsq_isMenuVisible
Expand Down
48 changes: 47 additions & 1 deletion JSQMessagesViewController/Layout/JSQMessagesCollectionViewFlowLayout.m
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -310,7 +310,53 @@ - (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
[self jsq_configureMessageCellLayoutAttributes:attributesItem];
}
else {
attributesItem.zIndex = -1;
// BEGIN HACK for Signal to fix scrolling crash.
//
// Signature of crash looks like this:
//
// 0 CoreFoundation 0x18cbe2fe0 __exceptionPreprocess + 124 (NSException.m:165)
// 1 libobjc.A.dylib 0x18b644538 objc_exception_throw + 56 (objc-exception.mm:521)
// 2 CoreFoundation 0x18cbe2eb4 +[NSException raise:format:arguments:] + 104 (NSException.m:131)
// 3 Foundation 0x18d67b760 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 112 (NSException.m:157)
// 4 UIKit 0x192d715c8 __45-[UICollectionViewData validateLayoutInRect:]_block_invoke + 1328 (UICollectionViewData.m:445)
// 5 UIKit 0x192d70ad4 -[UICollectionViewData validateLayoutInRect:] + 1496 (UICollectionViewData.m:559)
// 6 UIKit 0x193653184 -[UICollectionViewData layoutAttributesForCellsInRect:validateLayout:] + 148 (UICollectionViewData.m:885)
// 7 UIKit 0x19360f9f4 -[UICollectionView _computePrefetchCandidatesForVisibleBounds:futureVisibleBounds:prefetchVector:notifyDelegateIfNeeded:] + 132 (UICollectionView.m:2366)
// 8 UIKit 0x19360f954 -[UICollectionView _computePrefetchCandidatesForVelocity:notifyDelegateIfNeeded:] + 168 (UICollectionView.m:2361)
// 9 UIKit 0x19360f884 -[UICollectionView _prefetchItemsForVelocity:maxItemsToPrefetch:invalidateCandidatesOnDirectionChanges:] + 768 (UICollectionView.m:2308)
// 10 UIKit 0x192d701ac -[UICollectionView layoutSubviews] + 704 (UICollectionView.m:3586)
//
//
// Digging in a bit I can reliably reproduce the crash after ~10-30s of scrolling wildly while
// receiving messages (1/s). The failed assertion is:
//
// I verified that the problem goes away if we remove the "load earlier messages" supplemental view.
//
// For some reason, since prefetching was introduced in iOS10, this became more common.
//
// Another recent change in Signal wherein we're more aggressively invalidating our layout also made
// the occurrences of this crash jump.
//
// The actual assertion failure is like:
//
// layout attributes for supplementary item at index path (<NSIndexPath: 0xc000000000000016> {length = 2, path = 0 - 0}) changed from <JSQMessagesCollectionViewLayoutAttributes: 0x10ab8e860> index path: (<NSIndexPath: 0xc000000000000016> {length = 2, path = 0 - 0}); element kind: (UICollectionElementKindSectionHeader); frame = (0 0; 375 32); zIndex = 10; to <JSQMessagesCollectionViewLayoutAttributes: 0x10bc398f0> index path: (<NSIndexPath: 0xc000000000000016> {length = 2, path = 0 - 0}); element kind: (UICollectionElementKindSectionHeader); frame = (0 0; 375 32); zIndex = -1; without invalidating the layout
//
// Note the zIndex "changed" from 10 -> -1. This is the only place we touch the zIndex.
//
// The following line was introduced:
//
// commit 2c39325220e63535bc1a79b2d471e6c2e9d3d2a4
// Author: Jesse Squires <[email protected]>
// Date: Mon Jul 21 23:08:17 2014 -0700
//
// fix issue where header/footer failed to appear when springiness is enabled. close #409
//
// Since we're not using "springiness" we should be safe in disabling this.

// (Here's the actual code being commented out)
// attributesItem.zIndex = -1;

// END HACK for Signal to fix scrolling crash.
}
}];

Expand Down