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Joshua Gross
dd9fd2acac
Summary: For over a month I've been searching for a crash that occurs during Android's native `dispatchDraw` method on View. The stack traces didn't show anything useful - everything in the stack trace was native Android code, not React Native code. This also seems to only repro on certain vendors, and only on a very few React Native screens - I'm still not sure why either of those are the case, but from my repro, a *very* specific set of interactions needs to happen to trigger this crash. See comments inline and an example stack trace. Luckily, the fix is trivial. Since this code is used for animations, accessibility, and a number of other important interactions, I'm gating this change for now. In general we must be careful to only mutate the View hierarchy only when we /know/ for certain it is safe to do so. Indirectly mutating the View hierarchy during measure, onMeasure, layout, dispatchDraw, etc, can all be very dangerous. This is one of the last "escape hatches" that can cause view hierarchy modifications unexpectedly, so I think it's a very good idea to "secure" this further, and only update props synchronously here - and ensure that other MountItems like `Delete` are definitely /not/ executed here. Changelog: [Internal] Reviewed By: sammy-SC Differential Revision: D24639793 fbshipit-source-id: b6219ce882e8d2204b4d10bf99f6a1120a33cb5a