patch 8.1.1419: listener callbacks may be called recursively

Problem:    Listener callbacks may be called recursively.
Solution:   Set "updating_screen" while listener callbacks are invoked.

src/change.c

@@ -376,10 +376,18 @@ invoke_listeners(buf_T *buf)
     linenr_T	start = MAXLNUM;
     linenr_T	end = 0;
     linenr_T	added = 0;
+    int		save_updating_screen = updating_screen;
+    static int	recursive = FALSE;
 
     if (buf->b_recorded_changes == NULL  // nothing changed
-	    || buf->b_listener == NULL)  // no listeners
+	    || buf->b_listener == NULL   // no listeners
+	    || recursive)		 // already busy
 	return;
+    recursive = TRUE;
+
+    // Block messages on channels from being handled, so that they don't make
+    // text changes here.
+    ++updating_screen;
 
     argv[0].v_type = VAR_NUMBER;
     argv[0].vval.v_number = buf->b_fnum; // a:bufnr
@@ -418,6 +426,12 @@ invoke_listeners(buf_T *buf)
     --textlock;
     list_unref(buf->b_recorded_changes);
     buf->b_recorded_changes = NULL;
+
+    if (save_updating_screen)
+	updating_screen = TRUE;
+    else
+	after_updating_screen(TRUE);
+    recursive = FALSE;
 }
 #endif
 

src/proto/screen.pro

@@ -10,7 +10,7 @@ void redraw_buf_and_status_later(buf_T *buf, int type);
 int redraw_asap(int type);
 void redraw_after_callback(int call_update_screen);
 void redrawWinline(win_T *wp, linenr_T lnum);
-void reset_updating_screen(int may_resize_shell);
+void after_updating_screen(int may_resize_shell);
 void update_curbuf(int type);
 int update_screen(int type_arg);
 int conceal_cursor_line(win_T *wp);
@@ -18,7 +18,7 @@ void conceal_check_cursor_line(void);
 void update_debug_sign(buf_T *buf, linenr_T lnum);
 void updateWindow(win_T *wp);
 int screen_get_current_line_off(void);
-void screen_line(int row, int coloff, int endcol, int clear_width, int rlflag);
+void screen_line(int row, int coloff, int endcol, int clear_width, int flags);
 void rl_mirror(char_u *str);
 void status_redraw_all(void);
 void status_redraw_curbuf(void);

src/screen.c

@@ -506,8 +506,12 @@ redrawWinline(
     redraw_win_later(wp, VALID);
 }
 
+/*
+ * To be called when "updating_screen" was set before and now the postponed
+ * side effects may take place.
+ */
     void
-reset_updating_screen(int may_resize_shell UNUSED)
+after_updating_screen(int may_resize_shell UNUSED)
 {
     updating_screen = FALSE;
 #ifdef FEAT_GUI
@@ -803,7 +807,7 @@ update_screen(int type_arg)
     FOR_ALL_WINDOWS(wp)
 	wp->w_buffer->b_mod_set = FALSE;
 
-    reset_updating_screen(TRUE);
+    after_updating_screen(TRUE);
 
     /* Clear or redraw the command line.  Done last, because scrolling may
      * mess up the command line. */
@@ -886,7 +890,7 @@ update_finish(void)
     end_search_hl();
 # endif
 
-    reset_updating_screen(TRUE);
+    after_updating_screen(TRUE);
 
 # ifdef FEAT_GUI
     /* Redraw the cursor and update the scrollbars when all screen updating is

src/ui.c

@@ -691,7 +691,7 @@ ui_breakcheck_force(int force)
     if (save_updating_screen)
 	updating_screen = TRUE;
     else
-	reset_updating_screen(FALSE);
+	after_updating_screen(FALSE);
 
     recursive = FALSE;
 }

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1419,
 /**/
     1418,
 /**/