fix(events): trigger VimResume on next UI request (#24426)

src/nvim/api/ui.c

@@ -215,6 +215,8 @@ void nvim_ui_attach(uint64_t channel_id, Integer width, Integer height, Dictiona
 
   pmap_put(uint64_t)(&connected_uis, channel_id, ui);
   ui_attach_impl(ui, channel_id);
+
+  may_trigger_vim_suspend_resume(false);
 }
 
 /// @deprecated
@@ -237,6 +239,10 @@ void nvim_ui_set_focus(uint64_t channel_id, Boolean gained, Error *error)
     return;
   }
 
+  if (gained) {
+    may_trigger_vim_suspend_resume(false);
+  }
+
   do_autocmd_focusgained((bool)gained);
 }
 

src/nvim/api/vim.c

@@ -305,6 +305,7 @@ void nvim_feedkeys(String keys, String mode, Boolean escape_ks)
 Integer nvim_input(String keys)
   FUNC_API_SINCE(1) FUNC_API_FAST
 {
+  may_trigger_vim_suspend_resume(false);
   return (Integer)input_enqueue(keys);
 }
 
@@ -334,6 +335,8 @@ void nvim_input_mouse(String button, String action, String modifier, Integer gri
                       Integer col, Error *err)
   FUNC_API_SINCE(6) FUNC_API_FAST
 {
+  may_trigger_vim_suspend_resume(false);
+
   if (button.data == NULL || action.data == NULL) {
     goto error;
   }

src/nvim/autocmd.c

@@ -46,6 +46,7 @@
 #include "nvim/search.h"
 #include "nvim/state.h"
 #include "nvim/strings.h"
+#include "nvim/types.h"
 #include "nvim/ui.h"
 #include "nvim/ui_compositor.h"
 #include "nvim/vim.h"
@@ -2521,6 +2522,30 @@ static bool arg_autocmd_flag_get(bool *flag, char **cmd_ptr, char *pattern, int
   return false;
 }
 
+/// When kFalse: VimSuspend should be triggered next.
+/// When kTrue: VimResume should be triggerd next.
+/// When kNone: Currently triggering VimSuspend or VimResume.
+static TriState pending_vimresume = kFalse;
+
+static void vimresume_event(void **argv)
+{
+  apply_autocmds(EVENT_VIMRESUME, NULL, NULL, false, NULL);
+  pending_vimresume = kFalse;
+}
+
+/// Trigger VimSuspend or VimResume autocommand.
+void may_trigger_vim_suspend_resume(bool suspend)
+{
+  if (suspend && pending_vimresume == kFalse) {
+    pending_vimresume = kNone;
+    apply_autocmds(EVENT_VIMSUSPEND, NULL, NULL, false, NULL);
+    pending_vimresume = kTrue;
+  } else if (!suspend && pending_vimresume == kTrue) {
+    pending_vimresume = kNone;
+    multiqueue_put(main_loop.events, vimresume_event, 0);
+  }
+}
+
 // UI Enter
 void do_autocmd_uienter(uint64_t chanid, bool attached)
 {

src/nvim/ex_docmd.c

@@ -4874,12 +4874,9 @@ static void ex_stop(exarg_T *eap)
   if (!eap->forceit) {
     autowrite_all();
   }
-  apply_autocmds(EVENT_VIMSUSPEND, NULL, NULL, false, NULL);
-
+  may_trigger_vim_suspend_resume(true);
   ui_call_suspend();
   ui_flush();
-
-  apply_autocmds(EVENT_VIMRESUME, NULL, NULL, false, NULL);
 }
 
 /// ":exit", ":xit" and ":wq": Write file and quit the current window.