rpccall: extra arguments are silently ignored

[Synthetica9]

Description

When calling a function defined by @rpccall, extra arguments are silently ignored.

To reproduce

Run the following server:

from p4p.server.thread import SharedPV
from p4p.server import Server
from p4p.nt import NTScalar

pv = SharedPV(nt=NTScalar('d'), initial=0.0)

@pv.rpc
def on_rpc(pv, op):
    print("RPC Called!")
    print(op.value().query)
    op.done()

Server.forever([{'bar:foo': pv}])

Run the following client:

from p4p.rpc import rpcproxy, rpccall
from p4p.client.thread import Context

@rpcproxy
class MyProxy(object):
    @rpccall("%s:foo")
    # Single argument needed because #130
    def foo(a='d'):
        pass

ctx = Context()
proxy = MyProxy(ctx, format="bar")

# Should fail somehow:
proxy.foo(1, 2)

Observed behaviour

Running the client succeeds, but the server only gets a single argument. Relevant output:

RPC Called!
struct {
    double a = 1
}

Expected behaviour

Should fail with an exception, probably TypeError

[mdavidsaver]

Should fail with an exception, probably TypeError

Agreed. This would be done in the mcall() wrapper. Either directly, or maybe better in NTURI.wrap() where the zip() is implicitly discarding the extra positional argument.

https://github.com/mdavidsaver/p4p/blob/f5c96bad937fff57f5243f72b7fdb89a408d0f4a/src/p4p/rpc.py#L276-L279

https://github.com/mdavidsaver/p4p/blob/f5c96bad937fff57f5243f72b7fdb89a408d0f4a/src/p4p/nt/__init__.py#L275