4 files changed, 26 insertions, 39 deletions
diff --git a/src/nvim/api/ui.c b/src/nvim/api/ui.c
index 509032892b..4971753854 100644
--- a/src/nvim/api/ui.c
+++ b/src/nvim/api/ui.c
@@ -58,6 +58,21 @@ void remote_ui_disconnect(uint64_t channel_id)
   xfree(ui);
 }
 
+/// Wait until ui has connected on stdio channel.
+void remote_ui_wait_for_attach(void)
+  FUNC_API_NOEXPORT
+{
+  Channel *channel = find_channel(CHAN_STDIO);
+  if (!channel) {
+    // this function should only be called in --embed mode, stdio channel
+    // can be assumed.
+    abort();
+  }
+
+  LOOP_PROCESS_EVENTS_UNTIL(&main_loop, channel->events, -1,
+                            pmap_has(uint64_t)(connected_uis, CHAN_STDIO));
+}
+
 void nvim_ui_attach(uint64_t channel_id, Integer width, Integer height,
                     Dictionary options, Error *err)
   FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
diff --git a/src/nvim/channel.c b/src/nvim/channel.c
index 36423d0aa1..259f1cc600 100644
--- a/src/nvim/channel.c
+++ b/src/nvim/channel.c
@@ -432,7 +432,7 @@ uint64_t channel_from_stdio(bool rpc, CallbackReader on_output,
                             const char **error)
   FUNC_ATTR_NONNULL_ALL
 {
-  if (!headless_mode) {
+  if (!headless_mode && !embedded_mode) {
     *error = _("can only be opened in headless mode");
     return 0;
   }
diff --git a/src/nvim/main.c b/src/nvim/main.c
index 192e7d2907..4b838a837c 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -65,6 +65,7 @@
 #include "nvim/msgpack_rpc/helpers.h"
 #include "nvim/msgpack_rpc/server.h"
 #include "nvim/msgpack_rpc/channel.h"
+#include "nvim/api/ui.h"
 #include "nvim/api/private/defs.h"
 #include "nvim/api/private/helpers.h"
 #include "nvim/api/private/handle.h"
@@ -304,6 +305,7 @@ int main(int argc, char **argv)
   // Read ex-commands if invoked with "-es".
   //
   bool reading_tty = !headless_mode
+                     && !embedded_mode
                      && !silent_mode
                      && (params.input_isatty || params.output_isatty
                          || params.err_isatty);
@@ -348,18 +350,16 @@ int main(int argc, char **argv)
   // startup. This allows an external UI to show messages and prompts from
   // --cmd and buffer loading (e.g. swap files)
   bool early_ui = false;
-  if (embedded_mode) {
+  if (embedded_mode && !headless_mode) {
     TIME_MSG("waiting for embedder to make request");
-    rpc_wait_for_request();
+    remote_ui_wait_for_attach();
     TIME_MSG("done waiting for embedder");
 
-    if (ui_active()) {
-      // prepare screen now, so external UIs can display messages
-      starting = NO_BUFFERS;
-      screenclear();
-      early_ui = true;
-      TIME_MSG("initialized screen early for embedder");
-    }
+    // prepare screen now, so external UIs can display messages
+    starting = NO_BUFFERS;
+    screenclear();
+    early_ui = true;
+    TIME_MSG("initialized screen early for embedder");
   }
 
   // Execute --cmd arguments.
@@ -467,7 +467,7 @@ int main(int argc, char **argv)
     wait_return(true);
   }
 
-  if (!headless_mode && !silent_mode) {
+  if (!headless_mode && !embedded_mode && !silent_mode) {
     input_stop();  // Stop reading input, let the UI take over.
     ui_builtin_start();
   }
@@ -848,7 +848,6 @@ static void command_line_scan(mparm_T *parmp)
             headless_mode = true;
           } else if (STRICMP(argv[0] + argv_idx, "embed") == 0) {
             embedded_mode = true;
-            headless_mode = true;
             const char *err;
             if (!channel_from_stdio(true, CALLBACK_READER_INIT, &err)) {
               abort();
diff --git a/src/nvim/msgpack_rpc/channel.c b/src/nvim/msgpack_rpc/channel.c
index c6cfb1a9ce..3356cdc61e 100644
--- a/src/nvim/msgpack_rpc/channel.c
+++ b/src/nvim/msgpack_rpc/channel.c
@@ -40,8 +40,6 @@
 static PMap(cstr_t) *event_strings = NULL;
 static msgpack_sbuffer out_buffer;
 
-static bool got_stdio_request = false;
-
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "msgpack_rpc/channel.c.generated.h"
 #endif
@@ -331,9 +329,6 @@ static void handle_request(Channel *channel, msgpack_object *request)
     send_error(channel, request_id, error.msg);
     api_clear_error(&error);
     api_free_array(args);
-    if (channel->id == CHAN_STDIO) {
-      got_stdio_request = true;
-    }
     return;
   }
 
@@ -349,9 +344,6 @@ static void handle_request(Channel *channel, msgpack_object *request)
     if (is_get_mode && !input_blocking()) {
       // Defer the event to a special queue used by os/input.c. #6247
       multiqueue_put(ch_before_blocking_events, on_request_event, 1, evdata);
-      if (channel->id == CHAN_STDIO) {
-        got_stdio_request = true;
-      }
     } else {
       // Invoke immediately.
       on_request_event((void **)&evdata);
@@ -387,11 +379,6 @@ static void on_request_event(void **argv)
   channel_decref(channel);
   xfree(e);
   api_clear_error(&error);
-  bool is_api_info = handler.fn == handle_nvim_get_api_info;
-  // api info is used to initiate client library, ignore it
-  if (channel->id == CHAN_STDIO && !is_api_info) {
-    got_stdio_request = true;
-  }
 }
 
 static bool channel_write(Channel *channel, WBuffer *buffer)
@@ -757,17 +744,3 @@ static void log_msg_close(FILE *f, msgpack_object msg)
   log_unlock();
 }
 #endif
-
-/// Wait until embedder has done a request
-void rpc_wait_for_request(void)
-{
-  Channel *channel = find_rpc_channel(CHAN_STDIO);
-  if (!channel) {
-    // this function should only be called in --embed mode, stdio channel
-    // can be assumed.
-    abort();
-  }
-
-  LOOP_PROCESS_EVENTS_UNTIL(&main_loop, channel->events, -1, got_stdio_request);
-}
-