id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc	lang	patch	platform
1286	method overload in pir subclass of pmc pccmethod leaves object undefined	particle		"while creating a subclass of Exporter to test inter-language exports,
i stumbled across a bug that i can't seem to fix.

i've created a subclass of Exporter called MyExporter. MyExporter has
an overridden 'add_global' method, which adds a '&' sigil to each
global specified by the user and calls the method in the superclass.

i've also created a high-level language that uses the '&' sigil on
subs, and i import and aim to call the hll sub. however, the code
never finishes 'add_method', as it segfaults inside the supermethod
with an undefined 'exp' object. that is, from src/pmc/exporter.pmc,
line 260:

Parrot_Exporter *exp = PARROT_EXPORTER(SELF);

after this line, 'exp' is NULL, but 'SELF' (or after macro expansion
'pmc') is not. this is not the case when 'add_method' has not been
overridden. here's the pir code that exposes the bug:

.sub 'main' :main
.local pmc exp, ns

exp = new 'MyExporter'

ns = get_root_namespace ['foo']
exp.'source'( ns )

exp.'add_global'('bar')

say ""NEVER REACHES HERE""

exp.'import'()

'&bar'() ## THIS WILL SUCCEED!
'bar'() ## THIS WILL FAIL!
## THAT'S NOT WHAT I WANT!!!
.end


## create a subclass of Exporter that overrides 'add_global'
## it adds a '&' sigil to each requested global
.namespace ['MyExporter']
.sub 'onload' :load :init :anon
.local pmc class
class = subclass 'Exporter', 'MyExporter'
.return ()
.end


.sub 'add_global' :method
.param string glb :optional
.param int has_glb :opt_flag

.local pmc args, super
args = new .Hash
super = new .Super, self

unless has_glb goto no_global
glb = concat '&', glb
.return super.'add_global'( glb )
no_global:
.return super.'add_global'()
.end


# create a high-level language that uses '&' sigil for sub names
.HLL 'foo', ''
.sub '&bar'
say 'hello, world!'
.end


note that switching from a tail method call to a regular method call
has no effect.

also note that my code also exposes a problem with the current
Exporter implementation: the imported sub name does not match the
requested name. i have yet to address this as the current bug is
blocking progress.

~jerry"	bug	new	normal		library	trunk	medium