Use .at() method instead of operator[] for shareable worklet lookup

[tomekzaw]

Details

This PR partially fixes the following crash on Android:

react-native-live-markdown/cpp/MarkdownGlobal.cpp:40: std::shared_ptr<ShareableWorklet> expensify::livemarkdown::getMarkdownWorklet(const int): assertion "worklet != nullptr" failed

For some reason, getMarkdownWorklet is called for given parserId after unregisterMarkdownWorklet is called. The reason is currently unknown and will be investigated separately. In such case, globalMarkdownShareableWorklets[parserId] returns nullptr (and also stores nullptr in globalMarkdownShareableWorklets, sic!) and the assert fails.

After this change, in such case globalMarkdownShareableWorklets.at(parserId) will throw an exception. The exception will be passed through C++ code and then passed to Java side where it is already handled here:

react-native-live-markdown/android/src/main/java/com/expensify/livemarkdown/MarkdownParser.java

Lines 45 to 52 in 59e749c

	json = nativeParse(text, parserId);
	} catch (Exception e) {
	// Skip formatting, runGuarded will show the error in LogBox
	mPrevText = text;
	mPrevParserId = parserId;
	mPrevMarkdownRanges = Collections.emptyList();
	return mPrevMarkdownRanges;
	} finally {

Related Issues

• Crash assertion "worklet != nullptr" failed on Android #603
• [$250] Android - Workspace - App crashes when tapping on workspace share link as other user App#55195

Manual Tests

1. Apply the following changes:

diff --git a/example/src/App.tsx b/example/src/App.tsx
index 2d48a2b..b9b21e7 100644
--- a/example/src/App.tsx
+++ b/example/src/App.tsx
@@ -54,6 +54,11 @@ export default function App() {
 
   const ref = React.useRef<MarkdownTextInput>(null);
 
+  const parser = (markdown: string) => {
+    'worklet';
+    return parseExpensiMark(markdown);
+  };
+
   return (
     <View style={styles.container}>
       <PlatformInfo />
@@ -66,7 +71,7 @@ export default function App() {
         style={[styles.input, style]}
         ref={ref}
         markdownStyle={markdownStyle}
-        parser={parseExpensiMark}
+        parser={parser}
         placeholder="Type here..."
         onSelectionChange={e => setSelection(e.nativeEvent.selection)}
         selection={selection}
diff --git a/src/MarkdownTextInput.tsx b/src/MarkdownTextInput.tsx
index bff1928..0439547 100644
--- a/src/MarkdownTextInput.tsx
+++ b/src/MarkdownTextInput.tsx
@@ -105,8 +105,7 @@ const MarkdownTextInput = React.forwardRef<MarkdownTextInput, MarkdownTextInputP
 
   const parserId = React.useMemo(() => {
     return registerParser(props.parser);
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [workletHash]);
+  }, [props.parser]);
 
   React.useEffect(() => {
     return () => unregisterParser(parserId);

2. Build and launch the app on Android emulator
3. Place your cursor at the end of line > blockquote
4. Press a key multiple times

Linked PRs