patch 8.0.1731: characters deleted on completion

Problem:    Characters deleted on completion. (Adrià Farrés)
Solution:   Also check the last item for the ORIGINAL_TEXT flag. (Christian
            Brabandt, closes #1645)

Author: brammool

src/edit.c

@@ -3656,7 +3656,9 @@ ins_compl_set_original_text(char_u *str)
 {
     char_u	*p;
 
-    /* Replace the original text entry. */
+    /* Replace the original text entry.
+     * The ORIGINAL_TEXT flag is either at the first item or might possibly be
+     * at the last item for backward completion */
     if (compl_first_match->cp_flags & ORIGINAL_TEXT)	/* safety check */
     {
 	p = vim_strsave(str);
@@ -3666,6 +3668,16 @@ ins_compl_set_original_text(char_u *str)
 	    compl_first_match->cp_str = p;
 	}
     }
+    else if (compl_first_match->cp_prev != NULL
+	    && (compl_first_match->cp_prev->cp_flags & ORIGINAL_TEXT))
+    {
+       p = vim_strsave(str);
+       if (p != NULL)
+       {
+           vim_free(compl_first_match->cp_prev->cp_str);
+           compl_first_match->cp_prev->cp_str = p;
+       }
+    }
 }
 
 /*

src/testdir/test_popup.vim

@@ -814,5 +814,14 @@ func Test_popup_command()
   call delete('Xtest')
 endfunc
 
+func Test_popup_complete_backwards()
+  new
+  call setline(1, ['Post', 'Port', 'Po'])
+  let expected=['Post', 'Port', 'Port']
+  call cursor(3,2)
+  call feedkeys("A\<C-X>". repeat("\<C-P>", 3). "rt\<cr>", 'tx')
+  call assert_equal(expected, getline(1,'$'))
+  bwipe!
+endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -762,6 +762,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1731,
 /**/
     1730,
 /**/