Forbid source filters in Unicode evals

Source filters have always been byte-level filters.  Therefore they
don’t make sense on Unicode strings, unless we are planning to add
new APIs to support it.  Until then, croak.

1 files changed, 3 insertions, 0 deletions

diff --git a/toke.c b/toke.c
index 43ca704cc9..3720a83101 100644
--- a/toke.c
+++ b/toke.c
@@ -3839,6 +3839,9 @@ Perl_filter_add(pTHX_ filter_t funcp, SV *datasv)
     if (!PL_parser)
 	return NULL;
 
+    if (PL_parser->lex_flags & LEX_IGNORE_UTF8_HINTS)
+	Perl_croak(aTHX_ "Source filters apply only to byte streams");
+
     if (!PL_rsfp_filters)
 	PL_rsfp_filters = newAV();
     if (!datasv)