(Android) crash on TextInput onKeyPress when inputting an emoji via auto-complete

On 0.53.0 and later, including 0.54.2, if I input an emoji into a TextInput via auto-complete, the app crashes.

I’ve tracked down the root cause; I’ll put more details in a follow-up comment.

Environment

Environment:
  OS: macOS High Sierra 10.13.3
  Node: 9.7.1
  Yarn: 1.5.1
  npm: 5.6.0
  Watchman: 4.9.0
  Xcode: Xcode 9.2 Build version 9C40b
  Android Studio: Not Found

Packages: (wanted => installed)
  react: 16.2.0 => 16.2.0
  react-native: 0.53.3 => 0.53.3

Expected Behavior

No crash!

Actual Behavior

Crash stack:

Error calling RCTEventEmitter.receiveEvent

Failed to create Value from JSON: 
run
    NativeRunnable.java
handleCallback
    Handler.java:790
dispatchMessage
    Handler.java:99
dispatchMessage
    MessageQueueThreadHandler.java:31
loop
    Looper.java:164
run
    MessageQueueThreadImpl.java:194
run
    Thread.java:764

Steps to Reproduce

Fortunately, this repros with the example project from https://github.com/facebook/react-native/issues/18262 .

• Clone and run this repo https://github.com/lxcid/ReactNative-AndroidKeyPress
• Make sure you have an Android device attached for debugging.
• react-native run-android
• select the TextInput
• type ‘potato’
• tap the potato emoji that shows up in autocomplete.

[nickofthyme]

Are there any updates on this issue? Thanks

Update: Still present in 0.55.3

[akalin-keybase]

So the "Failed to create value from JSON: " exception is thrown from: https://github.com/facebook/react-native/blob/0ee502d1254b828efb119cc06bcd213c3d843269/ReactCommon/jschelpers/Value.cpp#L74 (i.e., it’s trying to parse JSON from an empty string)

Debugging this code, this is called from: https://github.com/facebook/react-native/blob/0ee502d1254b828efb119cc06bcd213c3d843269/ReactCommon/jschelpers/Value.cpp#L98

The conversion to JSON produces the string:

[258,"topKeyPress",{"key":"�"}]

(I’m not 100% sure if the �, which is supposed to be the potato emoji, is messed up because of the JSON conversion messing up or my debugging output.)

It is the String(ctx, json.c_str()) conversion that is failing and returning an empty string. This leads to the line https://github.com/facebook/react-native/blob/0ee502d1254b828efb119cc06bcd213c3d843269/ReactCommon/jschelpers/Value.h#L32

so it looks like JSC_JSStringCreateWithUTF8CString is having problems with the emoji character.