merge: assert that we're passed sane parameters
diff --git a/src/merge.c b/src/merge.c
index 547a65f..8855a26 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -3191,7 +3191,7 @@ int git_merge_analysis_for_ref(
int error = 0;
bool unborn;
- assert(analysis_out && preference_out && repo && their_heads);
+ assert(analysis_out && preference_out && repo && their_heads && their_heads_len > 0);
if (their_heads_len != 1) {
giterr_set(GITERR_MERGE, "can only merge a single branch");
@@ -3273,7 +3273,7 @@ int git_merge(
unsigned int checkout_strategy;
int error = 0;
- assert(repo && their_heads);
+ assert(repo && their_heads && their_heads_len > 0);
if (their_heads_len != 1) {
giterr_set(GITERR_MERGE, "can only merge a single branch");