X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pp.c;h=d63f03980906503491982cb9fc607a0b69f214e3;hb=c696a6a43b0b5a16f820f8a91db4e187fc9ac45b;hp=f9f9e7b82d917706718ee04ba1590ffca3be1223;hpb=a0cec76945276a0895c829a391529265d9b76bc0;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/pp.c b/pp.c
index f9f9e7b..d63f039 100644
--- a/pp.c
+++ b/pp.c
@@ -639,13 +639,22 @@ PP(pp_study)
 	if (SvSCREAM(sv))
 	    RETPUSHYES;
     }
-    else {
-	if (PL_lastscream) {
-	    SvSCREAM_off(PL_lastscream);
-	    SvREFCNT_dec(PL_lastscream);
-	}
-	PL_lastscream = SvREFCNT_inc(sv);
+    s = (unsigned char*)(SvPV(sv, len));
+    pos = len;
+    if (pos <= 0 || !SvPOK(sv)) {
+	/* No point in studying a zero length string, and not safe to study
+	   anything that doesn't appear to be a simple scalar (and hence might
+	   change between now and when the regexp engine runs without our set
+	   magic ever running) such as a reference to an object with overloaded
+	   stringification.  */
+	RETPUSHNO;
+    }
+
+    if (PL_lastscream) {
+	SvSCREAM_off(PL_lastscream);
+	SvREFCNT_dec(PL_lastscream);
     }
+    PL_lastscream = SvREFCNT_inc(sv);
 
     s = (unsigned char*)(SvPV(sv, len));
     pos = len;
@@ -4254,7 +4263,8 @@ PP(pp_reverse)
 	    sv_setsv(TARG, (SP > MARK)
 		    ? *SP
 		    : (padoff_du = find_rundefsvoffset(),
-			(padoff_du == NOT_IN_PAD || PAD_COMPNAME_FLAGS(padoff_du) & SVpad_OUR)
+			(padoff_du == NOT_IN_PAD
+			 || PAD_COMPNAME_FLAGS_isOUR(padoff_du))
 			? DEFSV : PAD_SVl(padoff_du)));
 	up = SvPV_force(TARG, len);
 	if (len > 1) {