fix(slate-react): prevent premature flush during composition for Andr…

.changeset/brave-dragons-write.md

@@ -0,0 +1,10 @@
+---
+'slate-react': patch
+---
+
+Fix Android handwriting input where first stroke commits prematurely on empty lines (e.g., '我' becomes '一我').
+
+**Cause:** When writing the first character of an empty line, Android handwriting triggers childList mutations (creating new DOM structure). These mutations get restored by RestoreDOM during React re-render, which interrupts the IME composition session.
+
+**Fix:** Skip flush during composition only when at the first character of an empty line. This targeted fix preserves normal onChange behavior for other scenarios while preventing the handwriting issue.
+

packages/slate-react/src/hooks/android-input-manager/android-input-manager.ts

@@ -123,7 +123,35 @@ export function createAndroidInputManager({
     action.run()
   }
 
+  // Helper: Check if cursor is at the first character of an empty line
+  const isAtEmptyLineFirstChar = (): boolean => {
+    const { selection, children } = editor
+    if (!selection) return false
+
+    const { anchor } = selection
+    // offset should be 0 or 1 (first char)
+    if (anchor.offset > 1) return false
+
+    // Get the block node at current path
+    const blockPath = anchor.path.slice(0, 1) // Get top-level path
+    const blockNode = children[blockPath[0]]
+    if (!blockNode) return true
+
+    // Check if this line/block is empty or has only one character
+    const text = Node.string(blockNode)
+    return text.length <= 1
+  }
+
   const flush = () => {
+    // FIX: Only skip flush during composition for empty line first char scenario.
+    // Android handwriting input triggers childList mutations when writing the first
+    // character of an empty line. These mutations get restored by RestoreDOM, which
+    // interrupts the IME composition and causes premature commits.
+    // See: https://github.com/ianstormtaylor/slate/issues/5979
+    if (IS_COMPOSING.get(editor) && isAtEmptyLineFirstChar()) {
+      return
+    }
+
     if (flushTimeoutId) {
       clearTimeout(flushTimeoutId)
       flushTimeoutId = null