hash-uni: bugfix.

* hash.c (hash_uni): The join function must only be called for
the values of keys that exist in both hashes. The broken logic
here unconditionally calls the join function for all keys in
the left hash (using nil as the right join value when the key
doesn't exist in the right hash).

1 files changed, 6 insertions, 2 deletions

diff --git a/hash.c b/hash.c
index 0b1f05a3..4242fd58 100644
--- a/hash.c
+++ b/hash.c
@@ -1380,8 +1380,12 @@ val hash_uni(val hash1, val hash2, val join_func)
       if (missingp(join_func)) {
         sethash(hout, car(entry), cdr(entry));
       } else {
-        loc ptr = gethash_l(self, hout, car(entry), nulloc);
-        set(ptr, funcall2(join_func, cdr(entry), deref(ptr)));
+        val new_p;
+        loc ptr = gethash_l(self, hout, car(entry), mkcloc(new_p));
+        if (new_p)
+          sethash(hout, car(entry), cdr(entry));
+        else
+          set(ptr, funcall2(join_func, cdr(entry), deref(ptr)));
       }
     }