Problem with cyclic type definition

[alendit]

Hello, please see https://github.com/alendit/babel-typecheck-circular-types for an example.

In main.js I define 2 types which reference each other. The function addBsToA takes an object of type A and a list of Bs and 'connects' them.

When I add a return type check in the line 11 typecheck breaks with an error about an infinite recursion. a flow check doesn't find any errors in main.js inself.

I realize that it's quite hard to check for circular dependencies at runtime and I'm not sure if you aim to support it. Since I haven't found any information about it in the docs and normal flow does seem to support this case, I think the difference should either be mentioned in the docs or the case should be supported.

[phpnode]

@alendit oh that's a nasty one. I'll have a think about what we can do to handle this more gracefully.

[alendit]

Two ideas:

• mark the parent objects with a private property _checked and check for this property in the child's checker before executing a recursive type check. The problem here would be that a dynamic property would greatly mess with V8's ability to optimize the code
• have a global set with checked items and check against it. Should be quite performant, since V8 will only keep the references, but only real-life tests will tell. Global object are not very pretty, though.

[phpnode]

Hi, sorry for taking so long to respond to this, this project is now deprecated in favour of https://codemix.github.io/flow-runtime which aims for full compatibility with Flow.

flow-runtime can deal with cyclic objects properly