Don't WARN when a spec matches no relevant targets.

This warning has its uses (e.g., if you accidentally ran on the wrong target),
but on balance, with hindsight, it seems more distracting and confusing than useful.

This is especially true with glob specs: "Run all the tests under foo/::" can
be satisfied vacuously if there are no tests under foo/::, so it's weird to
issue a warning.

In such cases we should adhere to the principle that "the empty set is not a
special case", and just let things hold vacuously.

Of course we can still ERROR when a goal absolutely needs a target in order
to make any sense at all.

[ci skip-rust]

[ci skip-build-wheels]

src/python/pants/core/goals/package.py

@@ -15,7 +15,6 @@
 from pants.engine.target import (
     AsyncFieldMixin,
     FieldSet,
-    NoApplicableTargetsBehavior,
     StringField,
     TargetRootsToFieldSets,
     TargetRootsToFieldSetsRequest,
@@ -96,7 +95,6 @@ async def package_asset(workspace: Workspace, dist_dir: DistDir) -> Package:
         TargetRootsToFieldSetsRequest(
             PackageFieldSet,
             goal_description="the `package` goal",
-            no_applicable_targets_behavior=NoApplicableTargetsBehavior.warn,
         ),
     )
     if not target_roots_to_field_sets.field_sets:

src/python/pants/core/goals/publish.py

@@ -39,7 +39,6 @@ async def publish_example(request: PublishToMyRepoRequest, ...) -> PublishProces
 from pants.engine.target import (
     FieldSet,
     ImmutableValue,
-    NoApplicableTargetsBehavior,
     TargetRootsToFieldSets,
     TargetRootsToFieldSetsRequest,
 )
@@ -191,15 +190,13 @@ async def run_publish(console: Console, publish: PublishSubsystem) -> Publish:
                 PackageFieldSet,
                 goal_description="",
                 # Don't warn/error here because it's already covered by `PublishFieldSet`.
-                no_applicable_targets_behavior=NoApplicableTargetsBehavior.ignore,
             ),
         ),
         Get(
             TargetRootsToFieldSets,
             TargetRootsToFieldSetsRequest(
                 PublishFieldSet,
                 goal_description="the `publish` goal",
-                no_applicable_targets_behavior=NoApplicableTargetsBehavior.warn,
             ),
         ),
     )

src/python/pants/core/goals/test.py

@@ -393,7 +393,6 @@ async def run_tests(
         TargetRootsToFieldSetsRequest(
             TestFieldSet,
             goal_description=f"the `{test_subsystem.name}` goal",
-            no_applicable_targets_behavior=NoApplicableTargetsBehavior.warn,
         ),
     )
     results = await MultiGet(

src/python/pants/engine/target.py

@@ -1278,7 +1278,7 @@ def __init__(
         field_set_superclass: Type[_FS],
         *,
         goal_description: str,
-        no_applicable_targets_behavior: NoApplicableTargetsBehavior,
+        no_applicable_targets_behavior: NoApplicableTargetsBehavior = NoApplicableTargetsBehavior.ignore,
         expect_single_field_set: bool = False,
     ) -> None:
         self.field_set_superclass = field_set_superclass