Bk/refactor model state batch updates#145
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bryankeller merged 2 commits intomasterfrom Oct 30, 2025
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Also update min iOS version to iOS 12
brynbodayle
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Oct 30, 2025
| inSectionAtIndex: indexPath.section) | ||
| else { | ||
| // On iOS 9, `layoutAttributesForItem(at:)` can be invoked for an index path of a new item | ||
| // before the layout is notified of this new item (through either `prepare` or |
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should we go ahead and clean up these comments referencing unsupported versions?
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Ah yeah, good idea, I can remove the comment in the next PR
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Details
This refactors how MagazineLayout tracks layout state when batch updates are happening. Previously, the
ModelStatewould store the current and previous section + item models. Many of theModelState's functions took aBatchUpdateStageparameter, allowingMagazineLayoutto ask for layout information for the.beforeUpdatesand.afterUpdatesstage.Rather than complicating all of these functions and having them handle the before and after updates stage, we can simply make a copy of the entire
ModelStatewhen batch updates occur, and store it asmodelStateBeforeBatchUpdates. This simplifies the signatures and implementations of many functions in theModelState, as they only need to operate on the section and item models that they know about.This also bumps the minimum iOS version to iOS 12, allowing us to remove some workarounds.
This is the first major step toward tracking a full layout "snapshot" when batch updates occur, which will simplify target-content-offset-related logic, and some other layout-metric-related logic as well. I created a prototype layout to test some of these ideas, and since they proved successful, I'm bring these ideas over to MagazineLayout.
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