Perl_newIO() can become a mathom by making newIO() a wrapper around newSV_type()

and tweaking Perl_sv_upgrade().

1 files changed, 15 insertions, 1 deletions

diff --git a/sv.c b/sv.c
index a5a3554337..b8daf81546 100644
--- a/sv.c
+++ b/sv.c
@@ -1430,8 +1430,22 @@ Perl_sv_upgrade(pTHX_ register SV *const sv, svtype new_type)
 	    SvNV_set(sv, 0);
 #endif
 
-	if (new_type == SVt_PVIO)
+	if (new_type == SVt_PVIO) {
+	    IO * const io = MUTABLE_IO(sv);
+	    GV *iogv = gv_fetchpvs("FileHandle::", 0, SVt_PVHV);
+
+	    SvOBJECT_on(io);
+	    /* Clear the stashcache because a new IO could overrule a package
+	       name */
+	    hv_clear(PL_stashcache);
+
+	    /* unless exists($main::{FileHandle}) and
+	       defined(%main::FileHandle::) */
+	    if (!(iogv && GvHV(iogv) && HvARRAY(GvHV(iogv))))
+		iogv = gv_fetchpvs("IO::Handle::", GV_ADD, SVt_PVHV);
+	    SvSTASH_set(io, MUTABLE_HV(SvREFCNT_inc(GvHV(iogv))));
 	    IoPAGE_LEN(sv) = 60;
+	}
 	if (old_type < SVt_PV) {
 	    /* referant will be NULL unless the old type was SVt_IV emulating
 	       SVt_RV */