🐛 Bug Report: Infinite Render Loop in FlashList v2 (setRenderId)

[Prajwaltechversant]

We encountered a crash in FlashList v2 (flashlist@2.x.x) that causes a maximum update depth exceeded error. This issue does not occur in FlashList v1, making it a regression.

error : "Render Error
Maximum update depth exceeded. This can happen when a component repeatedly calls setState inside componentWillUpdate or componentDidUpdate."

✅ Expected Behavior

FlashList should avoid triggering an infinite re-render loop when modifying layout or handling orientation changes.

🔄 Actual Behavior
FlashList v2 causes setRenderId to continuously update, triggering an infinite loop and crashing the app.

🔙 Regression
✅ Yes — this issue does not happen in v1, so it is a regression in v2.

✍️ Additional Notes
We tried using extraData and forcing keys to re-render, but it did not prevent the crash.

This may be linked to how modifyChildrenLayout() internally triggers updates.

[Prajwaltechversant]

@naqvitalha i got this crash both in debug and release. in v1 works fine without this crash

[Prajwaltechversant]

@naqvitalha i also tried this in flatlist, works fine there

[Prajwaltechversant]

@naqvitalha data={listData.filter(f => !!f)} or data={listData.slice()} fixes the crash ,data={[...listData])} fixes the crash , does this make any sense

[tsdevshop]

Issue appears to be coming from this line, which is setting state inside a useLayoutEffect with no deps. As a result, the state is set, component re-renders, which fires the useLayoutEffect, which sets the state, which re-renders the component... etc.

Perhaps we need a way to short-circuit this if the layout measurements aren't stable?

[naqvitalha]

Some more details or a repro will be helpful. This issue only happens when there's something wrong with list setup like duplicate keys in keyExtractor or having a list inside a ScrollView causing all items to render at one. If it's neither then I can look into it.

[Prajwaltechversant]

Hi @naqvitalha ,
I've verified that the keyExtractor is not generating any duplicate keys. The crash still occurs even when renderItem={null} or when the render component is not being used.

[AjayFrancisTechversant]

@naqvitalha , any updates on this?

[naqvitalha]

I'd appreciate a repro for this or some more details. A video might help too. We do render in a loop but it's always supposed to end unless your items keep changing their size or you're rendering too many to begin with (hundreds).
There can be some bug but since I don't have a repro, I can't do much. We also changed how we mount in alpha.21 so if this is happening on mount, you can try the new version.

[Prajwaltechversant]

HI @naqvitalha ,
I'll check that in the alpha version. Do you have an estimated timeline for the RC (release candidate) version?

[Prajwaltechversant]

Hi @naqvitalha , works fine in alpha release

[Gothamoo7]

@Prajwaltechversant @naqvitalha I'm getting the same issue in alpha.21 as well, if the list has more than 50 items.
Any workaround?

[Prajwaltechversant]

HI @Gothamoo7 , for me , the rendering issues is fixed in alpha 21.

[Prajwaltechversant]

@Gothamoo7 data={listData.filter(f => !!f)} or data={listData.slice()} fixes the crash ,data={[...listData])} fixes the crash , try this

[naqvitalha]

@Gothamoo7 Can you provide a repro (on expo snack) ? 50 items shouldn't cause this.