More generalized fix for #127855, overallocate in SvGROW and not just sv_grow()

If we overallocate in SvGROW() and not just sv_grow() we can ensure
we have more cases where we can COW. We need to ensure we always
have room for a null and a reference count.

1 files changed, 1 insertions, 1 deletions

diff --git a/sv.c b/sv.c
index 68df702b56..0200679087 100644
--- a/sv.c
+++ b/sv.c
@@ -4891,7 +4891,7 @@ Perl_sv_setpvn(pTHX_ SV *const sv, const char *const ptr, const STRLEN len)
     }
     SvUPGRADE(sv, SVt_PV);
 
-    dptr = SvGROW(sv, len + 2);
+    dptr = SvGROW(sv, len + 1);
     Move(ptr,dptr,len,char);
     dptr[len] = '\0';
     SvCUR_set(sv, len);