From d22e9465f6228207a4fe722ee84371c7817060d6 Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Tue, 15 Mar 2016 17:43:55 +0100
Subject: [PATCH] patch 7.4.1574 Problem:    ":undo 0" does not work. (Florent
 Fayolle) Solution:   Make it undo all the way. (closes #688)

---
 src/testdir/test_alot.vim       | 1 +
 src/testdir/test_undolevels.vim | 2 --
 src/undo.c                      | 9 ++++++++-
 src/version.c                   | 2 ++
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/testdir/test_alot.vim b/src/testdir/test_alot.vim
index 94ff8b1da..bd74afc4a 100644
--- a/src/testdir/test_alot.vim
+++ b/src/testdir/test_alot.vim
@@ -4,6 +4,7 @@
 source test_assign.vim
 source test_cursor_func.vim
 source test_delete.vim
+source test_ex_undo.vim
 source test_expand.vim
 source test_feedkeys.vim
 source test_file_perm.vim
diff --git a/src/testdir/test_undolevels.vim b/src/testdir/test_undolevels.vim
index 427cece24..7bb25effb 100644
--- a/src/testdir/test_undolevels.vim
+++ b/src/testdir/test_undolevels.vim
@@ -1,7 +1,5 @@
 " Tests for 'undolevels'
 
-set nocompatible viminfo+=nviminfo
-
 func FillBuffer()
   for i in range(1,13)
     put=i
diff --git a/src/undo.c b/src/undo.c
index 2bf815ba4..07b278130 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -2286,7 +2286,14 @@ undo_time(
      * Init "closest" to a value we can't reach. */
     if (absolute)
     {
-	target = step;
+	if (step == 0)
+	{
+	    /* target 0 does not exist, got to 1 and above it. */
+	    target = 1;
+	    above = TRUE;
+	}
+	else
+	    target = step;
 	closest = -1;
     }
     else
diff --git a/src/version.c b/src/version.c
index c3c932381..4779f7d87 100644
--- a/src/version.c
+++ b/src/version.c
@@ -743,6 +743,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1574,
 /**/
     1573,
 /**/
-- 
2.50.1