merge revision(s) edf01d4e82d8e44ee30ec41fbcb7f802bc8b8c5d: [Backport #18772]

	Treat NULL fake string as an empty string

	And the NULL string must be of size 0.
	---
	 string.c | 5 +++++
	 1 file changed, 5 insertions(+)

1 files changed, 5 insertions, 0 deletions

diff --git a/string.c b/string.c
index 4d55406dea..8f2a937758 100644
--- a/string.c
+++ b/string.c
@@ -414,6 +414,11 @@ setup_fake_str(struct RString *fake_str, const char *name, long len, int encidx)
     fake_str->basic.flags = T_STRING|RSTRING_NOEMBED|STR_NOFREE|STR_FAKESTR;
     /* SHARED to be allocated by the callback */
 
+    if (!name) {
+	RUBY_ASSERT_ALWAYS(len == 0);
+	name = "";
+    }
+
     ENCODING_SET_INLINED((VALUE)fake_str, encidx);
 
     RBASIC_SET_CLASS_RAW((VALUE)fake_str, rb_cString);