opt.output_format = DIFF_FORMAT_CALLBACK;
        opt.format_callback = update_index_from_diff;
 
-       read_cache();
        if (do_diff_cache(tree_sha1, &opt))
                return 1;
        diffcore_std(&opt);
 
 static void die_if_unmerged_cache(int reset_type)
 {
-       if (is_merge() || read_cache() < 0 || unmerged_cache())
+       if (is_merge() || unmerged_cache())
                die(_("Cannot do a %s reset in the middle of a merge."),
                    _(reset_type_names[reset_type]));
 
                }
        }
        *rev_ret = rev;
+
+       if (read_cache() < 0)
+               die(_("index file corrupt"));
+
        parse_pathspec(pathspec, 0,
                       PATHSPEC_PREFER_FULL |
+                      PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP |
                       (patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0),
                       prefix, argv);
 }
        if (patch_mode) {
                if (reset_type != NONE)
                        die(_("--patch is incompatible with --{hard,mixed,soft}"));
-               return run_add_interactive(sha1_to_hex(sha1), "--patch=reset", &pathspec);
+               return run_add_interactive(rev, "--patch=reset", &pathspec);
        }
 
        /* git reset tree [--] paths... can be used to