Is there a way to find out what particular BUILD file an error is coming from?

What error are you seeing? Usually the error messages do give useful context

If the BUILD file path is not in the error message, that's a bug.

Oh, and which version of Pants?

It is… SORT OF there. But, yeah.

21:56:06.07 [ERROR] 1 Exception encountered:

Engine traceback:
  in select
  in pants.vcs.changed.find_changed_owners
  in pants.backend.project_info.dependees.find_dependees
  in pants.backend.project_info.dependees.map_addresses_to_dependees
  in pants.engine.internals.graph.resolve_dependencies (integrations/mailbox/addin/src/integrations/mailbox/addin/__init__.py:../../../lib)
  in pants.backend.python.target_types_rules.validate_python_dependencies
  in pants.engine.internals.graph.resolve_target (requirements/python:structlog)
  in pants.engine.internals.graph.resolve_target_parametrizations (requirements/python:structlog)
  in pants.engine.internals.build_files.find_target_adaptor (requirements/python:structlog)
Traceback (most recent call last):
  File "/Users/user/.cache/pants/setup/bootstrap-Darwin-x86_64/2.12.0_py37/lib/python3.7/site-packages/pants/engine/internals/selectors.py", line 705, in native_engine_generator_send
    res = func.send(arg)
  File "/Users/user/.cache/pants/setup/bootstrap-Darwin-x86_64/2.12.0_py37/lib/python3.7/site-packages/pants/engine/internals/build_files.py", line 169, in find_target_adaptor
    namespace=address_family.namespace,
pants.base.exceptions.ResolveError: 'structlog' was not found in namespace 'requirements/python'. Did you mean one of:
  :python
Traceback (most recent call last):
  File "/Users/user/.cache/pants/setup/bootstrap-Darwin-x86_64/2.12.0_py37/lib/python3.7/site-packages/pants/bin/daemon_pants_runner.py", line 136, in single_daemonized_run
    cancellation_latch=cancellation_latch,
  File "/Users/user/.cache/pants/setup/bootstrap-Darwin-x86_64/2.12.0_py37/lib/python3.7/site-packages/pants/bin/local_pants_runner.py", line 162, in create
    session=graph_session.scheduler_session,
  File "/Users/user/.cache/pants/setup/bootstrap-Darwin-x86_64/2.12.0_py37/lib/python3.7/site-packages/pants/init/specs_calculator.py", line 67, in calculate_specs
    ChangedAddresses, [Params(changed_request, options_bootstrapper)]
  File "/Users/user/.cache/pants/setup/bootstrap-Darwin-x86_64/2.12.0_py37/lib/python3.7/site-packages/pants/engine/internals/scheduler.py", line 576, in product_request
    self._raise_on_error([t for _, t in throws])
  File "/Users/user/.cache/pants/setup/bootstrap-Darwin-x86_64/2.12.0_py37/lib/python3.7/site-packages/pants/engine/internals/scheduler.py", line 516, in _raise_on_error
    wrapped_exceptions=tuple(t.exc for t in throws),
pants.engine.internals.scheduler.ExecutionError: 1 Exception encountered:

Engine traceback:
  in select
  in pants.vcs.changed.find_changed_owners
  in pants.backend.project_info.dependees.find_dependees
  in pants.backend.project_info.dependees.map_addresses_to_dependees
  in pants.engine.internals.graph.resolve_dependencies (integrations/mailbox/addin/src/integrations/mailbox/addin/__init__.py:../../../lib)
  in pants.backend.python.target_types_rules.validate_python_dependencies
  in pants.engine.internals.graph.resolve_target (requirements/python:structlog)
  in pants.engine.internals.graph.resolve_target_parametrizations (requirements/python:structlog)
  in pants.engine.internals.build_files.find_target_adaptor (requirements/python:structlog)
Traceback (most recent call last):
  File "/Users/user/.cache/pants/setup/bootstrap-Darwin-x86_64/2.12.0_py37/lib/python3.7/site-packages/pants/engine/internals/selectors.py", line 705, in native_engine_generator_send
    res = func.send(arg)
  File "/Users/user/.cache/pants/setup/bootstrap-Darwin-x86_64/2.12.0_py37/lib/python3.7/site-packages/pants/engine/internals/build_files.py", line 169, in find_target_adaptor
    namespace=address_family.namespace,
pants.base.exceptions.ResolveError: 'structlog' was not found in namespace 'requirements/python'. Did you mean one of:
  :python


Use -ldebug for more logs. 
See <https://www.pantsbuild.org/v2.12/docs/troubleshooting> for common issues.
Consider reaching out for help: <https://www.pantsbuild.org/v2.12/docs/getting-help>

What was your pants command?

Yes, but I have to look in the fake traceback to find it out.. And,

./pants --changed-since=0e9f53550398c7c39b5b44662d353ee56628f3d6 --changed-dependees=transitive --tag=+foo release

Still that could be a better message!

It definitely could be. This one in particular was a mismerge, as I’m working on upgrading things other people are actually working. 🙂

@happy-kitchen-89482 the new error messages are in Pants 2.13. This was a ~week project to make these much better

When’s that supposed to come out, I’m already updating across 6 versions, might as well wait a bit and do 7 🙂

@witty-crayon-22786 hopefully end of next week? We know we have at least one more rc for a performance improvement, otherwise it's been used by several orgs for 2 weeks

I assume that was meant for me? 🙂

sort of, I was asking Stu if he agrees with my assessment

Ah. Okay.

yea, sounds right.

Okay, then 2.13 it is 🙂