describe: when failing, tell the user about options that work

diff --git a/builtin-read-tree.c b/builtin-read-tree.c
index 9c2d634d6d04c3ce08e1352adcba31b527fc08b1..14c836b1693317d5d834606e5613d7ceacb3189c 100644 (file)
--- a/builtin-read-tree.c
+++ b/builtin-read-tree.c
@@ -113,13 +113,15 @@ int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
        argc = parse_options(argc, argv, unused_prefix, read_tree_options,
                             read_tree_usage, 0);
 
-       if (read_cache_unmerged() && (opts.prefix || opts.merge))
-               die("You need to resolve your current index first");
-
        prefix_set = opts.prefix ? 1 : 0;
        if (1 < opts.merge + opts.reset + prefix_set)
                die("Which one? -m, --reset, or --prefix?");
-       stage = opts.merge = (opts.reset || opts.merge || prefix_set);
+
+       if (opts.reset || opts.merge || opts.prefix) {
+               if (read_cache_unmerged() && (opts.prefix || opts.merge))
+                       die("You need to resolve your current index first");
+               stage = opts.merge = 1;
+       }
 
        for (i = 0; i < argc; i++) {
                const char *arg = argv[i];