From f075187e57a0c1a267efc690f105452209b6ce40 Mon Sep 17 00:00:00 2001
From: DS Boyce <260543580+ds-boyce@users.noreply.github.com>
Date: Tue, 16 Jun 2026 09:25:34 -0700
Subject: [PATCH] Reset textarea height after clear (#10911)

---
 src/components/Composer/index.tsx          | 10 ++++++++++
 src/components/forms/AutosizedTextarea.tsx | 23 +++++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/src/components/Composer/index.tsx b/src/components/Composer/index.tsx
index b7a67f3033..b587d19eae 100644
--- a/src/components/Composer/index.tsx
+++ b/src/components/Composer/index.tsx
@@ -34,6 +34,7 @@ import {
 } from '#/components/Autocomplete'
 import {
   AutosizedTextarea,
+  type AutosizedTextareaHeightApi,
   type AutosizedTextareaProps,
 } from '#/components/forms/AutosizedTextarea'
 import {Span, Text} from '#/components/Typography'
@@ -150,6 +151,13 @@ export function Composer({
    */
   const inputScrollSharedValue = useSharedValue(0)
 
+  /*
+   * Imperative handle on the underlying textarea, used to reset its height when
+   * the input is cleared programmatically (Android doesn't fire
+   * `onContentSizeChange` in that case).
+   */
+  const heightApiRef = useRef<AutosizedTextareaHeightApi>(null)
+
   /*
    * Expose imperative internal API
    */
@@ -160,6 +168,7 @@ export function Composer({
       clear: () => {
         tapper.inputProps.onChangeText('')
         inputScrollSharedValue.value = 0
+        heightApiRef.current?.resetHeight()
       },
       insert: tapper.insert,
       setAutocompleteAnchor: sift.refs.setAnchor,
@@ -321,6 +330,7 @@ export function Composer({
           </View>
         )}
         <AutosizedTextarea
+          heightApiRef={heightApiRef}
           placeholderTextColor={t.palette.contrast_500}
           accessibilityLabel={label}
           accessibilityHint={label}
diff --git a/src/components/forms/AutosizedTextarea.tsx b/src/components/forms/AutosizedTextarea.tsx
index 402075ea27..7863f05eb6 100644
--- a/src/components/forms/AutosizedTextarea.tsx
+++ b/src/components/forms/AutosizedTextarea.tsx
@@ -1,4 +1,4 @@
-import {useMemo, useRef, useState} from 'react'
+import {useImperativeHandle, useMemo, useRef, useState} from 'react'
 import {
   TextInput,
   type TextInputContentSizeChangeEvent,
@@ -10,8 +10,18 @@ import {atoms as a, extractPadding, useAlf, web} from '#/alf'
 import {normalizeTextStyles} from '#/alf/typography'
 import {IS_ANDROID, IS_IOS, IS_WEB} from '#/env'
 
+export type AutosizedTextareaHeightApi = {
+  /**
+   * Reset the input back to its minimum height. Needed on Android, where the
+   * height is driven by state that only updates via `onContentSizeChange` -
+   * that event doesn't fire when the value is cleared programmatically.
+   */
+  resetHeight: () => void
+}
+
 export type AutosizedTextareaProps = Omit<TextInputProps, 'multiline'> & {
   ref?: React.Ref<TextInput>
+  heightApiRef?: React.Ref<AutosizedTextareaHeightApi>
   label: string
   minRows?: number
   maxRows?: number
@@ -20,6 +30,7 @@ export type AutosizedTextareaProps = Omit<TextInputProps, 'multiline'> & {
 
 export function AutosizedTextarea({
   ref,
+  heightApiRef,
   label,
   minRows = 1,
   maxRows,
@@ -107,6 +118,16 @@ export function AutosizedTextarea({
    * directly drive the `height`.
    */
   const [nativeHeight, setNativeHeight] = useState(minInputHeight)
+  useImperativeHandle(
+    heightApiRef,
+    () => ({
+      resetHeight: () => {
+        setNativeHeight(minInputHeight)
+        onUpdateHeight?.(minInputHeight)
+      },
+    }),
+    [minInputHeight, onUpdateHeight],
+  )
   const onContentSizeChange = (e: TextInputContentSizeChangeEvent) => {
     const contentSize = Math.ceil(e.nativeEvent.contentSize.height)
     // ios reports the content size without padding