Detect and disallow invalid connections in JSON

[tilk]

If the input JSON has a connection between different-sized ports, DigitalJS will happily connect them, with disastrous results. For example, yosys2digitaljs currently generates such a bad JSON for:

module test2(input [1:0] i, output o);
  assign o = i;
endmodule
module test(output o);
  test2 x(0'b1, o);
endmodule

[ialokim]

How would you like digitaljs to react in such a case? I would propose to show a warning/error (e.g. using a red shadow) on the affected wire (or port?), perhaps with a tooltip shown on mouseover stating the problem, and only allow circuit.start() in case there are no errors in the whole graph.

This would then also be another step towards #2 by handling invalid connections introduced by changing bit lengths after initialization.

[tilk]

Your proposition is fine. The information about the circuit correctness should also be accessible by code, for example by a property on HeadlessCircuit.
Also, I worry about complexity of the solution. It should be simple (so that it's easy to see it's correct), and should not impact the performance for error-free circuits.