hey folks, if I have a rule_helper with a Get, is there a way to multiget multiples of those? I thought I could just asyncio.gather, but there's not current event loop. The real problem I'm trying to solve: I need to factor out a part of a rule so I can use it in 2 places. I can't just create a new rule, since it depends on getting the subsystem, and subsystems are unhashable. So I can create a rule_helper, and that works in the original usage on 1 fieldset. Now I want to use that rule_helper in a place where I have multiple fieldsets. If this were a rule, I would MultiGet that. But it's a rule helper, so I can't just do that. I guess I could have the helper only marshall the arguments to the Get and use the 3arg form in the main function, but that feels clunky. I think that this question is interesting in the general case. I think "extract some code" and "put something in a forloop" are common operations, but I don't have a good intuition for how that's supposed to be done in Pants (esp with their interaction).

Instead of using a

rule_helper

, just turn the rule helper into a regular

rule

with its own request and result types.

I tried a rule at first, but I was hitting an issue where the subsystem wasn't hashable so

Get

with types the rule could satisfy were hitting TypeError: unhashable type: 'PythonInferSubsystem'

You shouldn't need to put a subsystem into the request type. Just make it be a parameter in the rule's signature and the Pants engine will automatically supply it.

Thanks! this works! my mind is blown and my paradigm is shifted

it's basically "dependency injection" with types and all statically validated. The rule graph errors are really confusing, but other than that, the engine is incredibly cool magic (the good type) 😄

"How the Pants engine works" sounds like it'd make a really cool blog post.