diff --git a/src/if_ruby.c b/src/if_ruby.c
index afa27ab..02b59dd 100644
--- a/src/if_ruby.c
+++ b/src/if_ruby.c
@@ -783,6 +783,7 @@
 {
     int state;
     linenr_T i;
+    buf_T   *was_curbuf = curbuf;
 
     if (ensure_ruby_initialized())
     {
@@ -792,6 +793,8 @@
 	{
 	    VALUE line;
 
+	    if (i > curbuf->b_ml.ml_line_count)
+		break;
 	    line = vim_str2rb_enc_str((char *)ml_get(i));
 	    rb_lastline_set(line);
 	    eval_enc_string_protect((char *) eap->arg, &state);
@@ -800,6 +803,8 @@
 		error_print(state);
 		break;
 	    }
+	    if (was_curbuf != curbuf)
+		break;
 	    line = rb_lastline_get();
 	    if (!NIL_P(line))
 	    {
diff --git a/src/testdir/test_ruby.vim b/src/testdir/test_ruby.vim
index 106ccb4..174467f 100644
--- a/src/testdir/test_ruby.vim
+++ b/src/testdir/test_ruby.vim
@@ -32,3 +32,20 @@
   redir END
   call assert_equal(['{"a"=>"foo", "b"=>123}'], split(l:out, "\n"))
 endfunc
+
+func Test_rubydo()
+  " Check deleting lines does not trigger ml_get error.
+  new
+  call setline(1, ['one', 'two', 'three'])
+  rubydo Vim.command("%d_")
+  bwipe!
+
+  " Check switching to another buffer does not trigger ml_get error.
+  new
+  let wincount = winnr('$')
+  call setline(1, ['one', 'two', 'three'])
+  rubydo Vim.command("new")
+  call assert_equal(wincount + 1, winnr('$'))
+  bwipe!
+  bwipe!
+endfunc
diff --git a/src/version.c b/src/version.c
index 476074f..44e5b6f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    270,
+/**/
     269,
 /**/
     268,