From 2f33460864283e84bb8aed43941708eb2f583747 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 2 Apr 2026 07:14:36 +0000
Subject: [PATCH] Add operations==-3 cancel drag support to glfwStartDrag

Agent-Logs-Url: https://github.com/kovidgoyal/kitty/sessions/eff7e2c8-ab7a-4967-95b5-e65631245701

Co-authored-by: kovidgoyal <1308621+kovidgoyal@users.noreply.github.com>
---
 glfw/cocoa_window.m | 11 +++++++++++
 glfw/glfw3.h        |  2 +-
 glfw/input.c        |  1 +
 glfw/internal.h     |  1 +
 glfw/wl_window.c    |  6 ++++++
 glfw/x11_window.c   | 11 +++++++++++
 6 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/glfw/cocoa_window.m b/glfw/cocoa_window.m
index 3f0c02962..baab680ca 100644
--- a/glfw/cocoa_window.m
+++ b/glfw/cocoa_window.m
@@ -4422,6 +4422,17 @@ _glfwPlatformStartDrag(_GLFWwindow* window, const GLFWimage* thumbnail) {@autore
 
 @end
 
+void
+_glfwPlatformCancelDrag(_GLFWwindow* window UNUSED) {@autoreleasepool{
+    if (!_glfw.drag.window_id) return;
+    _GLFWwindow* drag_win = _glfwWindowForId(_glfw.drag.window_id);
+    if (drag_win) {
+        GLFWDragEvent ev = {.type = GLFW_DRAG_CANCELLED};
+        _glfwInputDragSourceRequest(drag_win, &ev);
+    }
+    _glfwFreeDragSourceData();
+}}
+
 void
 _glfwPlatformFreeDragSourceData(void) {
     if (_glfw.ns.drag_session) [_glfw.ns.drag_session release];
diff --git a/glfw/glfw3.h b/glfw/glfw3.h
index 002e58b17..83890b617 100644
--- a/glfw/glfw3.h
+++ b/glfw/glfw3.h
@@ -4985,7 +4985,7 @@ GLFWAPI GLFWdragsourcefun glfwSetDragSourceCallback(GLFWwindow* window, GLFWdrag
 
 // Start a drag. If called with operations == -1 indicates that previously
 // requested data via GLFW_DRAG_DATA_REQUEST is ready. operations == -2 means
-// that the drag image is changed.
+// that the drag image is changed. operations == -3 cancels any existing drag.
 GLFWAPI int glfwStartDrag(GLFWwindow* window, const GLFWDragSourceItem *items, size_t mime_count, const GLFWimage* thumbnail, int operations, bool needs_toplevel_on_wayland);
 
 /*! @brief Returns whether the specified joystick is present.
diff --git a/glfw/input.c b/glfw/input.c
index 7f24f2137..c91eaf026 100644
--- a/glfw/input.c
+++ b/glfw/input.c
@@ -1190,6 +1190,7 @@ glfwStartDrag(GLFWwindow* handle, const GLFWDragSourceItem *items, size_t item_c
     _GLFW_REQUIRE_INIT_OR_RETURN(EINVAL);
     if (operations == -1) return _glfwPlatformDragDataReady(items[0].mime_type);
     if (operations == -2) return _glfwPlatformChangeDragImage(thumbnail);
+    if (operations == -3) { _glfwPlatformCancelDrag(window); return 0; }
     _glfwFreeDragSourceData();
     _glfw.drag.instance_id++;
     if (!items || !item_count) return 0;
diff --git a/glfw/internal.h b/glfw/internal.h
index 3821b403f..ea8f64521 100644
--- a/glfw/internal.h
+++ b/glfw/internal.h
@@ -835,6 +835,7 @@ void _glfwPlatformEndDrop(GLFWwindow *w, GLFWDragOperationType op);
 int _glfwPlatformRequestDropData(_GLFWwindow *window, const char *mime);
 // Platform functions for drag source
 int _glfwPlatformStartDrag(_GLFWwindow* window, const GLFWimage* thumbnail);
+void _glfwPlatformCancelDrag(_GLFWwindow* window);
 void _glfwFreeDragSourceData(void);
 void _glfwPlatformFreeDragSourceData(void);
 void _glfwInputDragSourceRequest(_GLFWwindow* window, GLFWDragEvent *ev);
diff --git a/glfw/wl_window.c b/glfw/wl_window.c
index c176915e9..ea0bc5983 100644
--- a/glfw/wl_window.c
+++ b/glfw/wl_window.c
@@ -3409,6 +3409,12 @@ static const struct wl_data_source_listener drag_source_listener = {
     .dnd_finished = drag_source_dnd_finished,
 };
 
+void
+_glfwPlatformCancelDrag(_GLFWwindow* window UNUSED) {
+    if (!_glfw.drag.window_id) return;
+    cancel_drag(GLFW_DRAG_CANCELLED);
+}
+
 void
 _glfwPlatformFreeDragSourceData(void) {
     if (_glfw.wl.drag.drag_viewport) wp_viewport_destroy(_glfw.wl.drag.drag_viewport);
diff --git a/glfw/x11_window.c b/glfw/x11_window.c
index 1924f8abf..b8d1f6f83 100644
--- a/glfw/x11_window.c
+++ b/glfw/x11_window.c
@@ -4522,6 +4522,17 @@ _glfwPlatformStartDrag(_GLFWwindow* window, const GLFWimage* thumbnail) {
     return 0;
 }
 
+void
+_glfwPlatformCancelDrag(_GLFWwindow* window UNUSED) {
+    if (!_glfw.drag.window_id) return;
+    _GLFWwindow* drag_win = _glfwWindowForId(_glfw.drag.window_id);
+    if (drag_win) {
+        GLFWDragEvent ev = {.type = GLFW_DRAG_CANCELLED};
+        _glfwInputDragSourceRequest(drag_win, &ev);
+    }
+    _glfwFreeDragSourceData();
+}
+
 void
 _glfwPlatformFreeDragSourceData(void) {
     if (_glfw.x11.drag.active) {