[Call-by-name] Investigate why so many intrinsic migrations are missing (e.g. Digest code)

[sureshjoshi]

This will end up being a larger ticket, as more of the codebase is converted to call-by-name syntax.

So instead of trying to bulk fill it in the existing PR and leave that rotting, better to cut that off more cleanly and move investigations to a separate ticket

[sureshjoshi]

@stuhood @benjyw

Trying to investigate why we have no migration data for the intrinsics.

As an example, there is no mention of RemovePrefix in the migration plan, even though those Gets are definitely there.

pants migrate-call-by-name --json | grep RemovePrefix

The associated intrinsic code appears to be present:

pants/src/rust/engine/src/intrinsics/mod.rs

Line 90 in d2a9a46

"remove_prefix_request_to_digest",

Ditto for the associated QueryRules:

pants/src/python/pants/engine/fs.py

Line 333 in d2a9a46

def rules():

So, I guess: Why is there no migration plan for intrinsics (it's more than just the filesystem, for example await Get(BuiltPackage, PackageFieldSet, field_set) also isn't present).

[sureshjoshi]

This feels like the missing piece of the puzzle.

pants/src/rust/engine/src/tasks.rs

Lines 185 to 196 in 572627f

	impl Intrinsic {
	pub fn new(name: &str, product: TypeId, input: TypeId) -> Self {
	// TODO: Python rule code that calls an intrinsic by name will need to be
	// able to import that name, so we'll need to create stubs representing the
	// intrinsics, in pants.engine.intrinsics.py.
	Self {
	id: RuleId::from_string(format!("pants.engine.intrinsics:{}", name)),
	product,
	inputs: vec![DependencyKey::new(input)],
	}
	}
	}