Ergonomic, hermetic, user-friendly software build system for Python, Go, Java, Kotlin, Protobuf, Scala, Shell. Pants lets you fearlessly scale up your codebase!

Pants

if we had more time, we'd be thinking about it now

<@U051221NF> : so you're more than welcome to dive in there

the code in src/python/pants/engine/legacy/graph.py is really just the bare minimum to adapt the existing model to something we can store in the graph

<@U051221NF> : the API for the engine itself is very, very tiny.

but the majority of what developers will interact with is the rest of what is exposed

Target objects, Sources fields, Subsystems

src/python/pants/engine/legacy/graph.py is ugly looking because it's centered around constructing the existing `BuildGraph` API

in particular, on a long enough time scale, the `BuildGraph` API goes away, because tasks made product requests up front

<@U051221NF> : a concrete example of <https://github.com/pantsbuild/pants/issues/3560> is that our adaptor for the existing BuildGraph API "hydrates" the arguments for Target constructors that way already... but only on a case-by-case basis where we recognize arguments to Targets that need additional hydration

so these tasks deal with "hydrating" particular target fields. <https://github.com/pantsbuild/pants/blob/master/src/python/pants/engine/legacy/graph.py#L320>

it's awkward because `Target` itself doesn't declare its fields

so one of the next steps i was thinking about was turning Target subclasses inside out and having a class method of `Target` containing a list of Field types that it will accept

(ie, declare the fields, rather than imperatively add them after construction)

I wonder if we could start out with the new python pipeline

It’s small and new enough to be tractable, but useful enough to be interesting

a real end to end usecase would be very useful, yes.

And we can create new target idioms for it if we want to

<@U051221NF> : yea, i think we're basically ready to help with that.

I’ll finish it up in the existing engine first

and since no one’s using it, we’re freer to mess with it

<@U054MQUPL> : where are the two post-fork locations again? found <https://github.com/pantsbuild/pants/blob/master/src/python/pants/bin/daemon_pants_runner.py#L148> ... but what was the first one?