Grow the buffer in case Unicode caused size changes

(and it very probably did).

p4raw-id: //depot/perl@14243

diff --git a/sv.c b/sv.c
index 3de686f..0e0c5fc 100644 (file)
--- a/sv.c
+++ b/sv.c
@@ -8362,10 +8362,8 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
        if (elen) {
            if (is_utf8 != has_utf8) {
                if (is_utf8) {
-                   if (SvCUR(sv)) {
+                   if (SvCUR(sv))
                        sv_utf8_upgrade(sv);
-                       p = SvEND(sv);
-                   }
                }
                else {
                    SV *nsv = sv_2mortal(newSVpvn(eptr, elen));
@@ -8373,6 +8371,8 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
                    eptr = SvPVX(nsv);
                    elen = SvCUR(nsv);
                }
+               SvGROW(sv, SvCUR(sv) + elen + 1);
+               p = SvEND(sv);
            }
            Copy(eptr, p, elen, char);
            p += elen;