+ &PL_sv_undef: seen on the left (oldstash)
+ &PL_sv_no : seen on the right (stash)
+ &PL_sv_yes : seen on both sides
+
+ */
+
+ if(oldstash) {
+ /* Add to the big list. */
+ struct mro_meta * meta;
+ HE * const entry
+ = (HE *)
+ hv_common(
+ seen_stashes, NULL, (const char *)&oldstash, sizeof(HV *), 0,
+ HV_FETCH_LVALUE|HV_FETCH_EMPTY_HE, NULL, 0
+ );
+ if(HeVAL(entry) == &PL_sv_undef || HeVAL(entry) == &PL_sv_yes) {
+ oldstash = NULL;
+ goto check_stash;
+ }
+ HeVAL(entry)
+ = HeVAL(entry) == &PL_sv_no ? &PL_sv_yes : &PL_sv_undef;
+ meta = HvMROMETA(oldstash);
+ (void)
+ hv_store(
+ stashes, (const char *)&oldstash, sizeof(HV *),
+ meta->isa
+ ? SvREFCNT_inc_simple_NN((SV *)meta->isa)
+ : &PL_sv_yes,
+ 0
+ );
+ CLEAR_LINEAR(meta);
+
+ /* Update the effective name. */
+ if(HvENAME_get(oldstash)) {
+ const HEK * const enamehek = HvENAME_HEK(oldstash);
+ if(SvTYPE(namesv) == SVt_PVAV) {
+ items = AvFILLp((AV *)namesv) + 1;
+ svp = AvARRAY((AV *)namesv);
+ }
+ else {
+ items = 1;
+ svp = &namesv;
+ }
+ while (items--) {
+ const U32 name_utf8 = SvUTF8(*svp);
+ STRLEN len;
+ const char *name = SvPVx_const(*svp, len);
+ if(PL_stashcache) {
+ DEBUG_o(Perl_deb(aTHX_ "mro_gather_and_rename clearing PL_stashcache for '%"SVf"'\n",
+ *svp));
+ (void)hv_delete(PL_stashcache, name, name_utf8 ? -(I32)len : (I32)len, G_DISCARD);
+ }
+ ++svp;
+ hv_ename_delete(oldstash, name, len, name_utf8);
+
+ if (!fetched_isarev) {
+ /* If the name deletion caused a name change, then we
+ * are not going to call mro_isa_changed_in with this
+ * name (and not at all if it has become anonymous) so
+ * we need to delete old isarev entries here, both
+ * those in the superclasses and this class's own list
+ * of subclasses. We simply delete the latter from
+ * PL_isarev, since we still need it. hv_delete morti-
+ * fies it for us, so sv_2mortal is not necessary. */
+ if(HvENAME_HEK(oldstash) != enamehek) {
+ if(meta->isa && HvARRAY(meta->isa))
+ mro_clean_isarev(meta->isa, name, len, 0, name_utf8);
+ isarev = (HV *)hv_delete(PL_isarev, name,
+ name_utf8 ? -(I32)len : (I32)len, 0);
+ fetched_isarev=TRUE;
+ }
+ }
+ }
+ }
+ }
+ check_stash:
+ if(stash) {
+ if(SvTYPE(namesv) == SVt_PVAV) {
+ items = AvFILLp((AV *)namesv) + 1;
+ svp = AvARRAY((AV *)namesv);
+ }
+ else {
+ items = 1;
+ svp = &namesv;
+ }
+ while (items--) {
+ const U32 name_utf8 = SvUTF8(*svp);
+ STRLEN len;
+ const char *name = SvPVx_const(*svp++, len);
+ hv_ename_add(stash, name, len, name_utf8);
+ }
+
+ /* Add it to the big list if it needs
+ * mro_isa_changed_in called on it. That happens if it was
+ * detached from the symbol table (so it had no HvENAME) before
+ * being assigned to the spot named by the 'name' variable, because
+ * its cached isa linearisation is now stale (the effective name
+ * having changed), and subclasses will then use that cache when
+ * mro_package_moved calls mro_isa_changed_in. (See
+ * [perl #77358].)
+ *
+ * If it did have a name, then its previous name is still
+ * used in isa caches, and there is no need for
+ * mro_package_moved to call mro_isa_changed_in.
+ */
+
+ entry
+ = (HE *)
+ hv_common(
+ seen_stashes, NULL, (const char *)&stash, sizeof(HV *), 0,
+ HV_FETCH_LVALUE|HV_FETCH_EMPTY_HE, NULL, 0
+ );
+ if(HeVAL(entry) == &PL_sv_yes || HeVAL(entry) == &PL_sv_no)
+ stash = NULL;
+ else {
+ HeVAL(entry)
+ = HeVAL(entry) == &PL_sv_undef ? &PL_sv_yes : &PL_sv_no;
+ if(!stash_had_name)
+ {
+ struct mro_meta * const meta = HvMROMETA(stash);
+ (void)
+ hv_store(
+ stashes, (const char *)&stash, sizeof(HV *),
+ meta->isa
+ ? SvREFCNT_inc_simple_NN((SV *)meta->isa)
+ : &PL_sv_yes,
+ 0
+ );
+ CLEAR_LINEAR(meta);
+ }
+ }
+ }
+
+ if(!stash && !oldstash)
+ /* Both stashes have been encountered already. */
+ return;
+
+ /* Add all the subclasses to the big list. */
+ if(!fetched_isarev) {
+ /* If oldstash is not null, then we can use its HvENAME to look up
+ the isarev hash, since all its subclasses will be listed there.
+ It will always have an HvENAME. It the HvENAME was removed
+ above, then fetch_isarev will be true, and this code will not be
+ reached.
+
+ If oldstash is null, then this is an empty spot with no stash in
+ it, so subclasses could be listed in isarev hashes belonging to
+ any of the names, so we have to check all of them.
+ */
+ assert(!oldstash || HvENAME(oldstash));
+ if (oldstash) {
+ /* Extra variable to avoid a compiler warning */
+ char * const hvename = HvENAME(oldstash);
+ fetched_isarev = TRUE;
+ svp = hv_fetch(PL_isarev, hvename,
+ HvENAMEUTF8(oldstash)
+ ? -HvENAMELEN_get(oldstash)
+ : HvENAMELEN_get(oldstash), 0);
+ if (svp) isarev = MUTABLE_HV(*svp);
+ }
+ else if(SvTYPE(namesv) == SVt_PVAV) {
+ items = AvFILLp((AV *)namesv) + 1;
+ svp = AvARRAY((AV *)namesv);
+ }
+ else {
+ items = 1;
+ svp = &namesv;
+ }
+ }