From b915e3317e0223f62e739145c50d2204ad1f20d5 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 28 Apr 2026 17:17:38 +0530
Subject: [PATCH] Drop protocol: have the final drop operation be reported at
 the end. This is needed for when there are errors in the client processing
 the dropped data.

---
 docs/dnd-protocol.rst |  6 ++++--
 kitty/dnd.c           | 18 ++++++++++++------
 kitty/dnd.h           |  2 +-
 kitty/screen.c        |  2 +-
 4 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/docs/dnd-protocol.rst b/docs/dnd-protocol.rst
index 097918f7b..1e066a21b 100644
--- a/docs/dnd-protocol.rst
+++ b/docs/dnd-protocol.rst
@@ -124,11 +124,13 @@ any error response means the drop is terminated.
 Once the client program finishes reading all the dropped data it needs, it must
 send an escape code of the form::
 
-    OSC _dnd_code ; t=r ST
+    OSC _dnd_code ; t=r:o=operation ST
 
 That is, it must send a request for data with no MIME type specified. The
 terminal emulator must then inform the OS that the drop is completed. Any
-queued data requests must be discarded by the terminal.
+queued data requests must be discarded by the terminal. The ``operation``
+is required and must specify the final action the client took with the data.
+If unset (aka ``0``) the terminal must assume the drop was canceled.
 
 Dropping from remote machines
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/kitty/dnd.c b/kitty/dnd.c
index ec718f3cd..f52b37e28 100644
--- a/kitty/dnd.c
+++ b/kitty/dnd.c
@@ -509,15 +509,20 @@ drop_move_on_child(Window *w, const char** mimes, size_t num_mimes, bool is_drop
     }
 }
 
+static GLFWDragOperationType
+drop_operation_to_enum(uint32_t op) {
+    switch(op) {
+        case 1: return GLFW_DRAG_OPERATION_COPY;
+        case 2: return GLFW_DRAG_OPERATION_MOVE;
+        default: return GLFW_DRAG_OPERATION_NONE;
+    }
+}
+
 void
 drop_set_status(Window *w, int operation, const char *payload, size_t payload_sz, bool more) {
     if (!w->drop.accept_in_progress) {
         drop_free_accepted_mimes(w); w->drop.accept_in_progress = true;
-        switch(operation) {
-            case 1: w->drop.accepted_operation = GLFW_DRAG_OPERATION_COPY; break;
-            case 2: w->drop.accepted_operation = GLFW_DRAG_OPERATION_MOVE; break;
-            default: w->drop.accepted_operation = GLFW_DRAG_OPERATION_NONE; break;
-        }
+        w->drop.accepted_operation = drop_operation_to_enum(operation);
     }
     if (payload_sz) {
         if (w->drop.accepted_mimes_sz + payload_sz > MIME_LIST_SIZE_CAP) return;
@@ -1144,8 +1149,9 @@ drop_process_queue(Window *w) {
 }
 
 void
-drop_enqueue_request(Window *w, int32_t cell_x, int32_t cell_y, int32_t pixel_y) {
+drop_enqueue_request(Window *w, int32_t cell_x, int32_t cell_y, int32_t pixel_y, uint32_t operation) {
     if (cell_x == 0 && cell_y == 0 && pixel_y == 0) {  // drop finished
+        w->drop.accepted_operation = drop_operation_to_enum(operation);
         drop_finish_and_clear_queue(w);
         reset_drop(w);
         return;
diff --git a/kitty/dnd.h b/kitty/dnd.h
index a1ed4effa..998c06ee4 100644
--- a/kitty/dnd.h
+++ b/kitty/dnd.h
@@ -16,7 +16,7 @@ void drop_left_child(Window *w);
 void drop_free_data(Window *w);
 void drop_send_einval(Window *w);
 void drop_handle_dir_request(Window *w, uint32_t handle_id, int32_t entry_num);
-void drop_enqueue_request(Window *w, int32_t cell_x, int32_t cell_y, int32_t pixel_y);
+void drop_enqueue_request(Window *w, int32_t cell_x, int32_t cell_y, int32_t pixel_y, uint32_t operation);
 void drop_set_status(Window *w, int operation, const char *payload, size_t payload_sz, bool more);
 size_t drop_update_mimes(Window *w, const char **allowed_mimes, size_t allowed_mimes_count);
 void drop_dispatch_data(Window *w, const char *mime_type, const char *data, ssize_t sz);
diff --git a/kitty/screen.c b/kitty/screen.c
index 0c7d16b2a..08f28908f 100644
--- a/kitty/screen.c
+++ b/kitty/screen.c
@@ -1535,7 +1535,7 @@ screen_handle_dnd_command(Screen *self, const DnDCommand *cmd, const uint8_t *pa
         case 'A': drop_register_window(w, NULL, 0, false, cmd->client_id, cmd->more); break;
         case 'm': drop_set_status(w, cmd->operation, (const char*)payload, cmd->payload_sz, cmd->more); break;
         case 'r': {
-            drop_enqueue_request(w, cmd->cell_x, cmd->cell_y, cmd->pixel_y);
+            drop_enqueue_request(w, cmd->cell_x, cmd->cell_y, cmd->pixel_y, cmd->operation);
         } break;
         case 'o': {
             switch (cmd->cell_x) {