From dd6b521bc72964ee492b1a2d51f2e92f85bf4dd6 Mon Sep 17 00:00:00 2001
From: Alejandro Alonso <alejandro.alonso@kaleidos.net>
Date: Fri, 21 Aug 2026 15:15:40 +0200
Subject: [PATCH] :bug: Fix WASM text selection copy to Windows apps (#11305)

Write text/html alongside text/plain on copy/cut so Windows apps that
prefer CF_HTML do not paste the empty contenteditable newline.
---
 .../ui/workspace/shapes/text/v3_editor.cljs   | 19 ++++++++++++++-----
 frontend/src/app/util/clipboard.cljs          | 12 ++++++++++++
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/frontend/src/app/main/ui/workspace/shapes/text/v3_editor.cljs b/frontend/src/app/main/ui/workspace/shapes/text/v3_editor.cljs
index 58377e9c1c..2563463d17 100644
--- a/frontend/src/app/main/ui/workspace/shapes/text/v3_editor.cljs
+++ b/frontend/src/app/main/ui/workspace/shapes/text/v3_editor.cljs
@@ -19,6 +19,7 @@
    [app.main.ui.css-cursors :as cur]
    [app.render-wasm.api :as wasm.api]
    [app.render-wasm.text-editor :as text-editor]
+   [app.util.clipboard :as clipboard]
    [app.util.dom :as dom]
    [app.util.keyboard :as kbd]
    [cuerdas.core :as str]
@@ -267,8 +268,13 @@
            (when (text-editor/text-editor-has-focus?)
              (dom/prevent-default event)
              (when (text-editor/text-editor-has-selection?)
-               (let [text (text-editor/text-editor-export-selection)]
-                 (.setData (.-clipboardData event) "text/plain" text))))))
+               (let [text (or (text-editor/text-editor-export-selection) "")
+                     html (clipboard/plain-text->html text)
+                     data (.-clipboardData event)]
+                 ;; text/html matters on Windows: many apps prefer CF_HTML, and
+                 ;; without it they can pick up the empty contenteditable `<br>`.
+                 (.setData data "text/plain" text)
+                 (.setData data "text/html" html))))))
 
         on-cut
         (mf/use-fn
@@ -276,9 +282,12 @@
            (when (text-editor/text-editor-has-focus?)
              (dom/prevent-default event)
              (when (text-editor/text-editor-has-selection?)
-               (let [text (text-editor/text-editor-export-selection)]
-                 (.setData (.-clipboardData event) "text/plain" (or text ""))
-                 (when (and text (seq text))
+               (let [text (or (text-editor/text-editor-export-selection) "")
+                     html (clipboard/plain-text->html text)
+                     data (.-clipboardData event)]
+                 (.setData data "text/plain" text)
+                 (.setData data "text/html" html)
+                 (when (seq text)
                    (text-editor/text-editor-delete-backward)
                    (sync-wasm-text-editor-content!)
                    (wasm.api/request-render-preserving-target "text-cut"))))
diff --git a/frontend/src/app/util/clipboard.cljs b/frontend/src/app/util/clipboard.cljs
index 3bc1f1bba3..c2c92c9a76 100644
--- a/frontend/src/app/util/clipboard.cljs
+++ b/frontend/src/app/util/clipboard.cljs
@@ -22,6 +22,18 @@
   #js {:decodeTransit t/decode-str
        :allowHTMLPaste false})
 
+(defn plain-text->html
+  "Build a minimal text/html clipboard payload from plain text.
+
+  Windows apps often prefer CF_HTML over CF_UNICODETEXT; writing only
+  text/plain from a contenteditable copy handler can leave them with the
+  editor surface's empty/`<br>` fallback (a lone newline)."
+  [text]
+  (let [escaped (-> (or text "")
+                    (dom/escape-html)
+                    (str/replace "\n" "<br>"))]
+    (str "<meta charset=\"utf-8\">" escaped)))
+
 (defn- from-data-transfer
   "Get clipboard stream from DataTransfer instance"
   ([data-transfer]