SVf_IsCOW

As discussed in ticket #114820, instead of using READONLY+FAKE to mark
a copy-on-write string, we should make it a separate flag.

There are many modules in CPAN (and 1 in core, Compress::Raw::Zlib)
that assume that SvREADONLY means read-only.  Only one CPAN module,
POSIX::pselect will definitely be broken by this.  Others may need to
be tweaked.  But I believe this is for the better.

It causes all tests except ext/Devel-Peek/t/Peek.t (which needs a tiny
tweak still) to pass under PERL_OLD_COPY_ON_WRITE, which is a prereq-
uisite for any new COW scheme that creates COWs under the same cir-
cumstances.

1 files changed, 1 insertions, 0 deletions

diff --git a/dump.c b/dump.c
index 015998325c..7a435e7776 100644
--- a/dump.c
+++ b/dump.c
@@ -1387,6 +1387,7 @@ const struct flag_to_name second_sv_flags_names[] = {
     {SVf_OOK, "OOK,"},
     {SVf_FAKE, "FAKE,"},
     {SVf_READONLY, "READONLY,"},
+    {SVf_IsCOW, "IsCOW,"},
     {SVf_BREAK, "BREAK,"},
     {SVf_AMAGIC, "OVERLOAD,"},
     {SVp_IOK, "pIOK,"},