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.