Get rid of warnings/exceptions at cleanup

After the encoding index instance variable is removed when all
instance variables are removed in `obj_free`, then `rb_str_free`
causes uninitialized instance variable warning and nil-to-integer
conversion exception.  Both cases result in object allocation
during GC, and crashes.

1 files changed, 1 insertions, 0 deletions

diff --git a/string.c b/string.c
index 3cfe3adcac..28a1b293d6 100644
--- a/string.c
+++ b/string.c
@@ -181,6 +181,7 @@ VALUE rb_cSymbol;
 
 #define STR_HEAP_PTR(str)  (RSTRING(str)->as.heap.ptr)
 #define STR_HEAP_SIZE(str) ((size_t)RSTRING(str)->as.heap.aux.capa + TERM_LEN(str))
+/* TODO: include the terminator size in capa. */
 
 #define STR_ENC_GET(str) get_encoding(str)