string.c: enable capacity when setting capa

* string.c (rb_str_modify_expand): enable capacity and disable
  assocation with packed objects when setting capa, so that
  pack("p") string fails to unpack properly after modified.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44803 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 0 deletions

diff --git a/string.c b/string.c
index ee57f92716..983c2a1166 100644
--- a/string.c
+++ b/string.c
@@ -1503,6 +1503,7 @@ rb_str_modify_expand(VALUE str, long expand)
 	int termlen = TERM_LEN(str);
 	if (!STR_EMBED_P(str)) {
 	    REALLOC_N(RSTRING(str)->as.heap.ptr, char, capa + termlen);
+	    STR_UNSET_NOCAPA(str);
 	    RSTRING(str)->as.heap.aux.capa = capa;
 	}
 	else if (capa + termlen > RSTRING_EMBED_LEN_MAX + 1) {