patch 8.0.1290: seq_cur of undotree() wrong after undo

Problem:    seq_cur of undotree() wrong after undo.
Solution:   Get the actual sequence number instead of decrementing the current
            one. (Ozaki Kiichi, closes #2319)

src/testdir/test_undo.vim

@@ -4,22 +4,82 @@
 " Also tests :earlier and :later.
 
 func Test_undotree()
-  exe "normal Aabc\<Esc>"
+  new
+
+  normal! Aabc
   set ul=100
-  exe "normal Adef\<Esc>"
-  set ul=100
-  undo
   let d = undotree()
-  call assert_true(d.seq_last > 0)
+  call assert_equal(1, d.seq_last)
-  call assert_true(d.seq_cur > 0)
+  call assert_equal(1, d.seq_cur)
-  call assert_true(d.seq_cur < d.seq_last)
+  call assert_equal(0, d.save_last)
-  call assert_true(len(d.entries) > 0)
+  call assert_equal(0, d.save_cur)
-  " TODO: check more members of d
+  call assert_equal(1, len(d.entries))
+  call assert_equal(1, d.entries[0].newhead)
+  call assert_equal(1, d.entries[0].seq)
+  call assert_true(d.entries[0].time <= d.time_cur)
+
+  normal! Adef
+  set ul=100
+  let d = undotree()
+  call assert_equal(2, d.seq_last)
+  call assert_equal(2, d.seq_cur)
+  call assert_equal(0, d.save_last)
+  call assert_equal(0, d.save_cur)
+  call assert_equal(2, len(d.entries))
+  call assert_equal(1, d.entries[0].seq)
+  call assert_equal(1, d.entries[1].newhead)
+  call assert_equal(2, d.entries[1].seq)
+  call assert_true(d.entries[1].time <= d.time_cur)
+
+  undo
+  set ul=100
+  let d = undotree()
+  call assert_equal(2, d.seq_last)
+  call assert_equal(1, d.seq_cur)
+  call assert_equal(0, d.save_last)
+  call assert_equal(0, d.save_cur)
+  call assert_equal(2, len(d.entries))
+  call assert_equal(1, d.entries[0].seq)
+  call assert_equal(1, d.entries[1].curhead)
+  call assert_equal(1, d.entries[1].newhead)
+  call assert_equal(2, d.entries[1].seq)
+  call assert_true(d.entries[1].time == d.time_cur)
+
+  normal! Aghi
+  set ul=100
+  let d = undotree()
+  call assert_equal(3, d.seq_last)
+  call assert_equal(3, d.seq_cur)
+  call assert_equal(0, d.save_last)
+  call assert_equal(0, d.save_cur)
+  call assert_equal(2, len(d.entries))
+  call assert_equal(1, d.entries[0].seq)
+  call assert_equal(2, d.entries[1].alt[0].seq)
+  call assert_equal(1, d.entries[1].newhead)
+  call assert_equal(3, d.entries[1].seq)
+  call assert_true(d.entries[1].time <= d.time_cur)
+
+  undo
+  set ul=100
+  let d = undotree()
+  call assert_equal(3, d.seq_last)
+  call assert_equal(1, d.seq_cur)
+  call assert_equal(0, d.save_last)
+  call assert_equal(0, d.save_cur)
+  call assert_equal(2, len(d.entries))
+  call assert_equal(1, d.entries[0].seq)
+  call assert_equal(2, d.entries[1].alt[0].seq)
+  call assert_equal(1, d.entries[1].curhead)
+  call assert_equal(1, d.entries[1].newhead)
+  call assert_equal(3, d.entries[1].seq)
+  call assert_true(d.entries[1].time == d.time_cur)
 
   w! Xtest
-  call assert_equal(d.save_last + 1, undotree().save_last)
+  let d = undotree()
+  call assert_equal(1, d.save_cur)
+  call assert_equal(1, d.save_last)
   call delete('Xtest')
-  bwipe Xtest
+  bwipe! Xtest
 endfunc
 
 func FillBuffer()

src/undo.c

@@ -2863,9 +2863,14 @@ u_undoredo(int undo)
     /* Remember where we are for "g-" and ":earlier 10s". */
     curbuf->b_u_seq_cur = curhead->uh_seq;
     if (undo)
+    {
 	/* We are below the previous undo.  However, to make ":earlier 1s"
 	 * work we compute this as being just above the just undone change. */
-	--curbuf->b_u_seq_cur;
+	if (curhead->uh_next.ptr != NULL)
+	    curbuf->b_u_seq_cur = curhead->uh_next.ptr->uh_seq;
+	else
+	    curbuf->b_u_seq_cur = 0;
+    }
 
     /* Remember where we are for ":earlier 1f" and ":later 1f". */
     if (curhead->uh_save_nr != 0)

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1290,
 /**/
     1289,
 /**/