Followup to 088225f/[perl #88132]: packages ending with :

Commit 088225f was not sufficient to fix the regression. It still
exists for packages whose names end with a single colon.

I discovered this when trying to determine why RDF::Trine was crashing
with 5.14-to-be.

In trying to write tests for it, I ended up triggering the same crash
that RDF::Trine is having, but in a different way.

In the end, it was easier to fix about three or four bugs (depending
on how you count them), rather than try to fix only the regression
that #88132 deals with (isa caches not updating when packages ending
with colons are aliased), as they are all intertwined.

The changes are as follows:

Concerning the if (!(flags & ~GV_NOADD_MASK)...) statement in
gv_stashpvn: Normally, gv_fetchpvn_flags (which it calls and whose
retval is assigned to tmpgv) returns NULL if it has not been told
to add anything and if the gv requested looks like a stash gv (ends
with ::). If the number of colons is odd (foo:::), that code path is
bypassed, so gv_stashpvn returns a GV without a hash. So gv_stashpvn
tries to used that NULL hash and crashes. It should instead return
NULL, to be consistent with the two-colon case.

Blindly assigning a name to a stash does not work if the stash has
multiple effective names. A call to mro_package_moved is required as
well. So what gv_stashpvn was doing was insufficient.

The parts of the mro code that check for globs or stash elems that
contain stashes by looking for :: at the end of the name now take into
account that the name might consist of a single : instead.

1 files changed, 7 insertions, 2 deletions

diff --git a/hv.c b/hv.c
index ed5061fb6d..56598d79fb 100644
--- a/hv.c
+++ b/hv.c
@@ -1026,7 +1026,11 @@ S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
 	if (HeVAL(entry) && HvENAME_get(hv)) {
 		gv = (GV *)HeVAL(entry);
 		if (keysv) key = SvPV(keysv, klen);
-		if (klen > 1 && key[klen-2] == ':' && key[klen-1] == ':'
+		if ((
+		     (klen > 1 && key[klen-2] == ':' && key[klen-1] == ':')
+		      ||
+		     (klen == 1 && key[0] == ':')
+		    )
 		 && (klen != 6 || hv!=PL_defstash || memNE(key,"main::",6))
 		 && SvTYPE(gv) == SVt_PVGV && (stash = GvHV((GV *)gv))
 		 && HvENAME_get(stash)) {
@@ -1780,7 +1784,8 @@ S_hfreeentries(pTHX_ HV *hv)
 		) {
 		    STRLEN klen;
 		    const char * const key = HePV(oentry,klen);
-		    if (klen > 1 && key[klen-1]==':' && key[klen-2]==':') {
+		    if ((klen > 1 && key[klen-1]==':' && key[klen-2]==':')
+		     || (klen == 1 && key[0] == ':')) {
 			mro_package_moved(
 			 NULL, GvHV(HeVAL(oentry)),
 			 (GV *)HeVAL(oentry), 0