I find this a bit unfortunate, that field validation is done lazily… 🧵

Where is this error being created? Most validation happens when creating Target, which is pretty eager. Even

list

should do the trick. But it's possible to raise InvalidFieldExceptiob inside a rule rather than via target API, which is lazy

The stacktrace for

list

is:

Engine traceback:
  in select
  in pants.backend.project_info.list_targets.list_targets
  in pants.engine.internals.graph.resolve_addresses_from_specs
  in pants.engine.internals.build_files.addresses_from_address_specs
  in pants.engine.internals.graph.resolve_unexpanded_targets
  in pants.engine.internals.graph.resolve_target (src/underpants:dist)
Traceback (most recent call last):
  File "/Users/aadt/.cache/pants/setup/bootstrap-Darwin-x86_64/pants.7zfHJF/install/lib/python3.9/site-packages/pants/engine/internals/selectors.py", line 705, in native_engine_generator_send
    res = func.send(arg)
  File "/Users/aadt/.cache/pants/setup/bootstrap-Darwin-x86_64/pants.7zfHJF/install/lib/python3.9/site-packages/pants/engine/internals/graph.py", line 191, in resolve_target
    target = target_type(target_adaptor.kwargs, address, union_membership)
  File "/Users/aadt/.cache/pants/setup/bootstrap-Darwin-x86_64/pants.7zfHJF/install/lib/python3.9/site-packages/pants/util/meta.py", line 188, in new_init
    prev_init(self, *args, **kwargs)
  File "/Users/aadt/.cache/pants/setup/bootstrap-Darwin-x86_64/pants.7zfHJF/install/lib/python3.9/site-packages/pants/engine/target.py", line 339, in __init__
    self.field_values = self._calculate_field_values(unhydrated_values, address)
  File "/Users/aadt/.cache/pants/setup/bootstrap-Darwin-x86_64/pants.7zfHJF/install/lib/python3.9/site-packages/pants/engine/target.py", line 356, in _calculate_field_values
    raise InvalidFieldException(
pants.engine.target.InvalidFieldException: Unrecognized field `repositories=['@pypi']` in target src/underpants:dist. Valid fields for the target type `python_distribution`: ['dependencies', 'description', 'entry_points', 'generate_setup', 'provides', 'sdist', 'sdist_config_settings', 'tags', 'wheel', 'wheel_config_settings'].

And similar for

package

Weird that

publish

doesn't create the

Target

, given that it calls

package

under-the-hood?

Well, no, I guess it isn’t, as it’ll will only call

package

for targets that also has a

publish

field set. And with that backend missing, there isn’t one for

python_distribution

Ah ha, cool. Then this is all expected 🙂

So the “unfortunate” bit is perhaps more that there isn’t a “validate all my targets” goal.. you only get that as a side effect of using your targets.

that there isn’t a “validate all my targets” goal.

The fastest way to do that is

./pants list :: > /dev/null

Right!

[cli.alias]
validate-targets = "list ::"

but.. there’s no redirection support there…. 🤔

You could easily create a plugin goal based on

list_targets.py

if you were motivated enough. Don't have it write to

Console

. I think it literally would do nothing more than request

Targets

in the rule signature

Haha, yeah, true 🙂

Depends how useful it is to your org. I personally would instead use

./pants list :: > /dev/null  # Validate all targets

in my CI and wouldn't even bother with creating a

[cli].alias

because I wouldn't expect users to be running it daily

no true, and I wouldn’t be running this in CI, oh wait, maybe that’s a neat idea actually, to pre-emptively check that all targets are well defined.