merge-recursive: add sanity checks for relevant merge_options

There are lots of options that callers can set, yet most have a limited
range of valid values, some options are meant for output (e.g.
opt->obuf, which is expected to start empty), and callers are expected
to not set opt->priv.  Add several sanity checks to ensure callers
provide sane values.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/merge-recursive.c b/merge-recursive.c
index fa3f8eb0b261747b8238744753be9fda1cb527b6..0231d7b04983d6c7f923122f14586dd565863d49 100644 (file)
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -3615,6 +3615,30 @@ static int merge_start(struct merge_options *opt, struct tree *head)
 {
        struct strbuf sb = STRBUF_INIT;
 
+       /* Sanity checks on opt */
+       assert(opt->repo);
+
+       assert(opt->branch1 && opt->branch2);
+
+       assert(opt->detect_renames >= -1 &&
+              opt->detect_renames <= DIFF_DETECT_COPY);
+       assert(opt->detect_directory_renames >= MERGE_DIRECTORY_RENAMES_NONE &&
+              opt->detect_directory_renames <= MERGE_DIRECTORY_RENAMES_TRUE);
+       assert(opt->rename_limit >= -1);
+       assert(opt->rename_score >= 0 && opt->rename_score <= MAX_SCORE);
+       assert(opt->show_rename_progress >= 0 && opt->show_rename_progress <= 1);
+
+       assert(opt->xdl_opts >= 0);
+       assert(opt->recursive_variant >= MERGE_VARIANT_NORMAL &&
+              opt->recursive_variant <= MERGE_VARIANT_THEIRS);
+
+       assert(opt->verbosity >= 0 && opt->verbosity <= 5);
+       assert(opt->buffer_output <= 2);
+       assert(opt->obuf.len == 0);
+
+       assert(opt->priv == NULL);
+
+       /* Sanity check on repo state; index must match head */
        if (repo_index_has_changes(opt->repo, head, &sb)) {
                err(opt, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
                    sb.buf);