onGloballyPositioned is always requesting remeasure on recomposition [186109675]

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Bug

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Description

po...@google.com

created issue #1

Apr 22, 2021 03:07PM

It seems that onGloballyPositioned always requests remeasurement on recomposition.

When setting a new modifier we are doing:

if (layoutState == Ready && addedCallback) {
   // We need to notify the callbacks of a change in position since there's
   // a new one.
   requestRemeasure()
}

and here addedCallback will always be true, because Modifier.onGloballyPositioned is always creating a new object on recomposition. Fixing this might require an API change as onGloballyPositioned is currently inline, so we cannot use the lambda instance to check for modifier equality across recomposition.

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an...@google.com <an...@google.com> May 17, 2021 03:07PM

Reassigned to an...@google.com.

ap...@google.com <ap...@google.com> #2May 19, 2021 11:23AM

Marked as fixed.

Project: platform/frameworks/support
Branch: androidx-main

commit 35e722280155d3e6135d2a1f4f4ed6e0ef01314c
Author: Andrey Kulikov <andreykulikov@google.com>
Date: Mon May 17 16:58:01 2021

Remove inline from Modifier.onSizeChanged() and Modifier.onGloballyPositioned()

This allows us to make such modifier skippable. Currently if something triggers recomposition in the function invoking such modifiers those functions will always return a modifier which is not equals to the previous one, causing unnecessary recompositions and remeasurings.

Fixes: 188417479
Fixes: 186109675
Test: ./gradlew bOS
Relnote: Modifier.onSizeChanged() and Modifier.onGloballyPositioned() are not inlined functions anymore
Change-Id: I727f6622174806efb68b63808b322e6bc86e1cf5

M compose/ui/ui/api/1.0.0-beta08.txt
M compose/ui/ui/api/current.txt
M compose/ui/ui/api/public_plus_experimental_1.0.0-beta08.txt
M compose/ui/ui/api/public_plus_experimental_current.txt
M compose/ui/ui/api/restricted_1.0.0-beta08.txt
M compose/ui/ui/api/restricted_current.txt
M compose/ui/ui/src/androidAndroidTest/kotlin/androidx/compose/ui/layout/OnGloballyPositionedTest.kt
M compose/ui/ui/src/androidAndroidTest/kotlin/androidx/compose/ui/layout/OnSizeChangedTest.kt
M compose/ui/ui/src/commonMain/kotlin/androidx/compose/ui/layout/OnGloballyPositionedModifier.kt
M compose/ui/ui/src/commonMain/kotlin/androidx/compose/ui/layout/OnRemeasuredModifier.kt

https://android-review.googlesource.com/1708420

Issue 186109675

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an...@google.com <an...@google.com> May 17, 2021 03:07PM

ap...@google.com <ap...@google.com> #2May 19, 2021 11:23AM

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