agent macro inheritance doesn't work correctly if two types are defined in different modules with the same name

[Tortar]

E.g. something like

julia> module A
           export X
           using Agents
           @agent struct X(NoSpaceAgent) end
       end
Main.A

julia> module B
           using Agents
           @agent struct X(NoSpaceAgent) a::Int end
       end
Main.B

julia> using Agents

julia> @agent struct Y(X) end

julia> Y(1) # should work, but it doesn't
ERROR: MethodError: no method matching Y(::Int64)
...

julia> Y(1, 1) # shouldn't work, but it does
Y(1, 1)

That is because our book-keeping doesn't preserve the module where the inherited agent belongs to:

julia> Agents.__AGENT_GENERATOR__
Dict{Symbol, Expr} with 8 entries:
  :GraphAgent      => :(mutable struct GraphAgent <: Agents.AbstractAgent…
  :GridAgent       => :(mutable struct GridAgent{D} <: Agents.AbstractAgent…
  :A               => :(mutable struct A <: Agents.AbstractAgent…
  :X               => :(mutable struct X <: Agents.AbstractAgent…
  :OSMAgent        => :(mutable struct OSMAgent <: Agents.AbstractAgent…
  :NoSpaceAgent    => :(mutable struct NoSpaceAgent <: AbstractAgent…
  :Y               => :(mutable struct Y <: Agents.AbstractAgent…
  :ContinuousAgent => :(mutable struct ContinuousAgent{D, T} <: Agents.AbstractAgent…

[Datseris]

In the example above which module did you use? There is no using statement beyond Agents.

[Datseris]

I would think that the Y(X) would error because X is an undefined variable.

[Tortar]

ohh yeah there is also this other problem, since we access X from Agents.__AGENT_GENERATOR__ we can access it if an agent with that name was defined in any module, even if that agent type wasn't exported. Same fix for the problem I found would apply to this case too, namely preserving the module information in the book-keeping

[Datseris]

But still, what is the plan here? To check if the calling code contains the module that defined the agent? I don't know how you check whether a module has been used or not, programmatically. You can't use isdefined, because in the above examples modules A, B are defined, they just aren't using.

[Tortar]

It should be built at runtime so that we can obtain the module location of the variable e.g.

julia> module A
           export X
           struct X end
       end;

julia> using .A

julia> macro m(x)
           quote parentmodule($x) end
       end;

julia> @m(X)
Main.A

[Tortar]

and the book-keeping should be like

julia> Agents.__AGENT_GENERATOR__
Dict{Symbol, Expr} with 8 entries:
  (Agents, :GraphAgent)  => :(mutable struct GraphAgent <: Agents.AbstractAgent…
  (Agents, :GridAgent)       => :(mutable struct GridAgent{D} <: Agents.AbstractAgent…
  (A, :X)             => :(mutable struct X <: Agents.AbstractAgent…
  (B, :X)             => :(mutable struct X <: Agents.AbstractAgent…
  (Main, :Y)              => :(mutable struct Y <: Agents.AbstractAgent…
  ...