From acfacede2d96fb6adf59b826491d3339d5d95261 Mon Sep 17 00:00:00 2001
From: Luke Parker <10430890+Hona@users.noreply.github.com>
Date: Thu, 17 Sep 2026 09:47:00 +1000
Subject: [PATCH] fix(app): preserve native clipboard paste (#49424)

---
 .../src/composer/editor/interaction.test.ts   | 19 +++++++++++++++
 .../app/src/composer/editor/interaction.ts    | 24 ++++++++++++-------
 2 files changed, 34 insertions(+), 9 deletions(-)
 create mode 100644 packages/app/src/composer/editor/interaction.test.ts

diff --git a/packages/app/src/composer/editor/interaction.test.ts b/packages/app/src/composer/editor/interaction.test.ts
new file mode 100644
index 00000000000..145cd30de01
--- /dev/null
+++ b/packages/app/src/composer/editor/interaction.test.ts
@@ -0,0 +1,19 @@
+import { expect, test } from "bun:test"
+import { shouldHandlePasteAsAttachment } from "./interaction"
+
+test("leaves paste to the browser when web clipboard data is unavailable", () => {
+  expect(shouldHandlePasteAsAttachment(clipboard(), false)).toBe(false)
+})
+
+test("uses native image reading only when the clipboard has no text", () => {
+  expect(shouldHandlePasteAsAttachment(clipboard(), true)).toBe(true)
+  expect(shouldHandlePasteAsAttachment(clipboard(["text/plain"]), true)).toBe(false)
+})
+
+test("handles clipboard files as attachments", () => {
+  expect(shouldHandlePasteAsAttachment(clipboard([], [{ kind: "file" }]), false)).toBe(true)
+})
+
+function clipboard(types: string[] = [], items: Array<{ kind: string }> = []) {
+  return { types, items } as unknown as DataTransfer
+}
diff --git a/packages/app/src/composer/editor/interaction.ts b/packages/app/src/composer/editor/interaction.ts
index c94e71bc3cc..c779a0efc16 100644
--- a/packages/app/src/composer/editor/interaction.ts
+++ b/packages/app/src/composer/editor/interaction.ts
@@ -384,20 +384,20 @@ export function createComposerEditor(input: {
     },
     onPaste(event: ClipboardEvent) {
       const clipboard = event.clipboardData
-      if (
-        attachments &&
-        (Array.from(clipboard?.items ?? []).some((item) => item.kind === "file") || !clipboard?.getData("text/plain"))
-      ) {
+      const text = clipboard?.getData("text/plain")
+      if (attachments && shouldHandlePasteAsAttachment(clipboard, !!input.attachments?.readClipboardImage)) {
         void attachments.handlePaste(event)
         return
       }
-      const text = clipboard?.getData("text/plain").replace(/\r\n?/g, "\n")
       if (!text) return
       event.preventDefault()
       // insertText emits input events per line, repeatedly parsing and saving the draft.
       // Escaped HTML inserts multiline text once and preserves native selection and undo.
-      const multiline = text.includes("\n")
-      const value = multiline ? text.replaceAll("&", "&amp;").replaceAll("<", "&lt;").replaceAll(">", "&gt;") : text
+      const normalized = text.replace(/\r\n?/g, "\n")
+      const multiline = normalized.includes("\n")
+      const value = multiline
+        ? normalized.replaceAll("&", "&amp;").replaceAll("<", "&lt;").replaceAll(">", "&gt;")
+        : normalized
       if (
         typeof document.execCommand === "function" &&
         document.execCommand(multiline ? "insertHTML" : "insertText", false, value)
@@ -408,13 +408,13 @@ export function createComposerEditor(input: {
       if (!(target instanceof HTMLElement) || !selection?.rangeCount || !target.contains(selection.anchorNode)) return
       const range = selection.getRangeAt(0)
       range.deleteContents()
-      const node = document.createTextNode(text)
+      const node = document.createTextNode(normalized)
       range.insertNode(node)
       range.setStartAfter(node)
       range.collapse(true)
       selection.removeAllRanges()
       selection.addRange(range)
-      target.dispatchEvent(new InputEvent("input", { bubbles: true, inputType: "insertFromPaste", data: text }))
+      target.dispatchEvent(new InputEvent("input", { bubbles: true, inputType: "insertFromPaste", data: normalized }))
     },
     onDragEnter(event: DragEvent) {
       event.preventDefault()
@@ -450,6 +450,12 @@ export function createComposerEditor(input: {
 
 export type ComposerEditorModel = ReturnType<typeof createComposerEditor>
 
+export function shouldHandlePasteAsAttachment(clipboard: DataTransfer | null, readClipboardImage: boolean) {
+  if (Array.from(clipboard?.items ?? []).some((item) => item.kind === "file")) return true
+  if (Array.from(clipboard?.types ?? []).some((type) => type.startsWith("text/"))) return false
+  return readClipboardImage
+}
+
 function canNavigateHistory(direction: "up" | "down", text: string, cursor: number, inHistory: boolean) {
   const position = Math.max(0, Math.min(cursor, text.length))
   if (inHistory) return position === 0 || position === text.length