Fix null pointer crash in Scheduler::animationTick by adding null check for uiManager_ (#56128) (#56128)

[shubhamksavita]

Summary:

Changelog: [Android] [Fixed] - Fix crash in Scheduler::animationTick when uiManager_ is null.

Test Plan:
CI

Fixes a null pointer dereference crash in Scheduler::animationTick() that occurs during shutdown race conditions.

Root Cause Analysis

The Symptom: uiManager_ is null when Scheduler::animationTick() is called, causing a crash at offset 0x50 from null when accessing members of UIManager.

The Root Cause: During shutdown, when uninstallFabricUIManager() is called, the Choreographer's animation frame callback (doFrame) can still arrive. While FabricUIManagerBinding::driveCxxAnimations() checks for null scheduler (added in D92986523), the internal Scheduler::animationTick() method didn't check if uiManager_ is valid before dereferencing it:

void Scheduler::animationTick() const {
  uiManager_->animationTick();  // No null check - crashes if uiManager_ is null
}

The Fix: Added a null check for uiManager_ before accessing it, following the same defensive pattern used in driveCxxAnimations() and other methods in the codebase:

void Scheduler::animationTick() const {
  if (!uiManager_) {
    return;
  }
  uiManager_->animationTick();
}

Why This Fix Works: It prevents the null pointer dereference by checking uiManager_ validity before use. During shutdown, if the scheduler is accessed after uiManager_ becomes invalid, the method will safely return instead of crashing.

Related Diffs

• D92986523: Similar fix for null scheduler check in driveCxxAnimations()

Logview link: b3d4c4d8f7e6dd50b09fb7df9a1ad66a

CI

Differential Revision: D93363797

Pulled By: shubhamksavita

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@shubhamksavita has exported this pull request. If you are a Meta employee, you can view the originating Diff in D93363797.

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Review automatically exported from Phabricator review in Meta.

[meta-codesync]

@shubhamksavita merged this pull request in e73592b.