Restore debug hints for test execution (pantsbuild#17406)

Closes pantsbuild#17386

91d68f1 broke streaming output for `test`. This commit should fix the problem by having the new partitioning API's types subclass `EngineAwareParameter`.

For now I've only implemented `debug_hint` for the `TestRequest.Batch` type, because it's the direct replacement for the old `TestFieldSet`-driven API.

src/python/pants/base/specs_integration_test.py

@@ -80,8 +80,8 @@ def test_address_literal() -> None:
         assert run(["list", *list_specs]).stdout.splitlines() == list_specs
 
         test_result = run(["test", f"{tmpdir}/py:tests"]).stderr
-        assert f"{tmpdir}/py/utils/strutil_test.py:../tests succeeded" in test_result
-        assert f"{tmpdir}/py/base/common_test.py:../tests succeeded" in test_result
+        assert f"{tmpdir}/py/utils/strutil_test.py:../tests - succeeded." in test_result
+        assert f"{tmpdir}/py/base/common_test.py:../tests - succeeded." in test_result
         assert f"{tmpdir}/py:tests" not in test_result
 
 
@@ -109,14 +109,14 @@ def test_sibling_addresses() -> None:
         # Even though no `python_test` targets are explicitly defined in `util/`, a generated
         # target is resident there.
         test_result = run(["test", f"{tmpdir}/py/utils:"]).stderr
-        assert f"{tmpdir}/py/utils/strutil_test.py:../tests succeeded" in test_result
+        assert f"{tmpdir}/py/utils/strutil_test.py:../tests - succeeded." in test_result
         assert f"{tmpdir}/py/base/common_test.py:../tests" not in test_result
         assert f"{tmpdir}/py:tests" not in test_result
 
         # Even though no `_test.py` files live in this dir, we match the `python_tests` target
         # and replace it with its generated targets.
         test_result = run(["test", f"{tmpdir}/py:"]).stderr
-        assert f"{tmpdir}/py/utils/strutil_test.py:../tests succeeded" in test_result
+        assert f"{tmpdir}/py/utils/strutil_test.py:../tests - succeeded." in test_result
         assert f"{tmpdir}/py/base/common_test.py:../tests" in test_result
         assert f"{tmpdir}/py:tests" not in test_result
 
@@ -137,7 +137,7 @@ def test_descendent_addresses() -> None:
         ]
 
         test_result = run(["test", f"{tmpdir}/py::"]).stderr
-        assert f"{tmpdir}/py/utils/strutil_test.py:../tests succeeded" in test_result
+        assert f"{tmpdir}/py/utils/strutil_test.py:../tests - succeeded." in test_result
         assert f"{tmpdir}/py/base/common_test.py:../tests" in test_result
         assert f"{tmpdir}/py:tests" not in test_result
 

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

@@ -21,7 +21,6 @@
     EnvironmentNameRequest,
 )
 from pants.core.util_rules.partitions import (
-    PartitionElementT,
     PartitionerType,
     PartitionMetadataT,
     Partitions,
@@ -311,12 +310,13 @@ def tool_name(cls) -> str:
 
     @distinct_union_type_per_subclass(in_scope_types=[EnvironmentName])
     class PartitionRequest(_PartitionFieldSetsRequestBase[_TestFieldSetT]):
-        pass
+        def metadata(self) -> dict[str, Any]:
+            return {"addresses": [field_set.address.spec for field_set in self.field_sets]}
 
     @distinct_union_type_per_subclass(in_scope_types=[EnvironmentName])
-    class Batch(_BatchBase[PartitionElementT, PartitionMetadataT]):
+    class Batch(_BatchBase[_TestFieldSetT, PartitionMetadataT]):
         @property
-        def single_element(self) -> PartitionElementT:
+        def single_element(self) -> _TestFieldSetT:
             """Return the single element of this batch.
 
             NOTE: Accessing this property will raise a `TypeError` if this `Batch` contains
@@ -334,6 +334,18 @@ def single_element(self) -> PartitionElementT:
 
             return self.elements[0]
 
+        def debug_hint(self) -> str:
+            if len(self.elements) == 1:
+                return self.elements[0].address.spec
+
+            return f"{self.elements[0].address.spec} and {len(self.elements)-1} other files"
+
+        def metadata(self) -> dict[str, Any]:
+            return {
+                "addresses": [field_set.address.spec for field_set in self.elements],
+                "partition_description": self.partition_metadata.description,
+            }
+
     @classmethod
     def rules(cls) -> Iterable:
         yield from cls.partitioner_type.default_rules(cls, by_file=False)

src/python/pants/core/util_rules/partitions.py

@@ -14,6 +14,7 @@
 
 from pants.core.goals.multi_tool_goal_helper import SkippableSubsystem
 from pants.engine.collection import Collection
+from pants.engine.engine_aware import EngineAwareParameter
 from pants.engine.internals.selectors import Get, MultiGet
 from pants.engine.rules import collect_rules, rule
 from pants.engine.target import (
@@ -154,7 +155,7 @@ def single_partition(
 @frozen_after_init
 @dataclass(unsafe_hash=True)
 @runtime_ignore_subscripts
-class _BatchBase(Generic[PartitionElementT, PartitionMetadataT]):
+class _BatchBase(Generic[PartitionElementT, PartitionMetadataT], EngineAwareParameter):
     """Base class for a collection of elements that should all be processed together.
 
     For example, a collection of strings pointing to files that should be linted in one process, or
@@ -168,7 +169,7 @@ class _BatchBase(Generic[PartitionElementT, PartitionMetadataT]):
 
 @dataclass(frozen=True)
 @runtime_ignore_subscripts
-class _PartitionFieldSetsRequestBase(Generic[_FieldSetT]):
+class _PartitionFieldSetsRequestBase(Generic[_FieldSetT], EngineAwareParameter):
     """Returns a unique type per calling type.
 
     This serves us 2 purposes:
@@ -180,7 +181,7 @@ class _PartitionFieldSetsRequestBase(Generic[_FieldSetT]):
 
 
 @dataclass(frozen=True)
-class _PartitionFilesRequestBase:
+class _PartitionFilesRequestBase(EngineAwareParameter):
     """Returns a unique type per calling type.
 
     This serves us 2 purposes: