react / react/react-native

<View /> doesn't recalculate it's size when a descendant <Text /> changes height due to wrapping following a device rotation

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Bug Component: View Issue: Author Provided Repro
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Descrizione

🐛 Bug Report

I believe I've found a bug in the View size calculation logic in React Native. In certain cases, the ancestor View fails to recalculate its size if a descendant <Text /> component changes in size due to a rotation and subsequent text (re)wrapping.

The following shows three states: initial, rotated, and back to original orientation. Notice that the fuschia view "grows" after returning to the original orientation.

Initial orientation
image
Portrait
image
Back to initial orientation
image

Speculative Analysis and Workaround

This appears to be an issue where an ancestor view caches a layout calculation and doesn't trigger a re-calculation when a nested Text component changes in size due to orientation changes.

After some playing around, we've figured out that if you "poke" any of the style properties that affect the view's style layout, the view will recalculate and be correct. We did this by toggling a state var upon rotation and then adding/removing a style object to the view's styles array that contained an extra paddingBottom that mirrored the existing padding on the view (basically we changed the style but the effect had no changes to the layout).

You can see a demo of the workaround by uncommenting the line of code below the FIXME comment in the code sample.

To Reproduce

See the code, but basically if you have a <ScrollView> that contains a container <View> which contains another <View> and then have a <Text> element inside that view... this layout bug will happen. I haven't been able to reduce this example further than that.

Expected Behavior

After rotating and going back to the initial orientation, the View should be exactly the same size.

Code Example

Github repo: https://github.com/jeremywiebe/react-native-text-orientation-bug

Environment

  React Native Environment Info:
    System:
      OS: macOS 10.14.2
      CPU: (8) x64 Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
      Memory: 34.97 MB / 16.00 GB
      Shell: 3.0.0 - /usr/local/bin/fish
    Binaries:
      Node: 8.15.0 - /usr/local/bin/node
      Yarn: 1.13.0 - /usr/local/bin/yarn
      npm: 6.4.1 - /usr/local/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 12.1, macOS 10.14, tvOS 12.1, watchOS 5.1
      Android SDK:
        API Levels: 23, 25, 27
        Build Tools: 23.0.1, 25.0.0, 25.0.2, 25.0.3, 27.0.3, 28.0.1, 28.0.2, 28.0.3
        System Images: android-16 | Intel x86 Atom, android-16 | Google APIs Intel x86 Atom, android-19 | Intel x86 Atom, android-19 | Google APIs Intel x86 Atom, android-23 | Google APIs Intel x86 Atom_64, android-24 | Google APIs Intel x86 Atom, android-24 | Google Play Intel x86 Atom, android-25 | Google APIs Intel x86 Atom, android-28 | Google Play Intel x86 Atom
    IDEs:
      Android Studio: 3.1 AI-173.4907809
      Xcode: 10.1/10B61 - /usr/bin/xcodebuild
    npmPackages:
      react: 16.6.3 => 16.6.3 
      react-native: 0.58.4 => 0.58.4 

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  3. Fai un fork del repository e lavora su un branch.
  4. Apri una pull request che faccia riferimento al numero della issue.

Direzione di ricerca

Inizia dal repository di riproduzione collegato e riproduci la sequenza di rotazione che coinvolge ScrollView, componenti View annidati e il ritorno a capo di Text. Leggi la logica di calcolo delle dimensioni di View descritta nel report e confronta gli orientamenti iniziale, verticale e ripristinato. Il lavoro è completato quando il View antenato torna esattamente alle stesse dimensioni senza il workaround di modifica dello stile.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Valutazione

Stack tecnologico
react-native
Ambito
mobile-dev
Tipo di issue
Bug
Difficoltà
4/5
Tempo stimato
3-5 giorni
Stato di attività
Ferma
Chiarezza
Abbastanza chiara
Idoneità per principianti
35/100

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