Add --debug-adapter flag to test goal

build-support/bin/_generate_all_lockfiles_helper.py

@@ -29,6 +29,7 @@
 from pants.backend.python.lint.pylint.subsystem import Pylint
 from pants.backend.python.lint.pyupgrade.subsystem import PyUpgrade
 from pants.backend.python.lint.yapf.subsystem import Yapf
+from pants.backend.python.subsystems.debugpy import DebugPy
 from pants.backend.python.subsystems.ipython import IPython
 from pants.backend.python.subsystems.lambdex import Lambdex
 from pants.backend.python.subsystems.pytest import PyTest
@@ -104,6 +105,7 @@ def jvm(cls, tool: type[JvmToolBase], *, backend: str | None = None) -> DefaultT
     DefaultTool.python(Pylint, backend="pants.backend.python.lint.pylint", source_plugins=True),
     DefaultTool.python(Yapf, backend="pants.backend.python.lint.yapf"),
     DefaultTool.python(PyUpgrade, backend="pants.backend.experimental.python.lint.pyupgrade"),
+    DefaultTool.python(DebugPy),
     DefaultTool.python(IPython),
     DefaultTool.python(Setuptools),
     DefaultTool.python(SetuptoolsSCM),

src/python/pants/backend/go/goals/test.py

@@ -28,7 +28,13 @@
 from pants.backend.go.util_rules.import_analysis import ImportConfig, ImportConfigRequest
 from pants.backend.go.util_rules.link import LinkedGoBinary, LinkGoBinaryRequest
 from pants.backend.go.util_rules.tests_analysis import GeneratedTestMain, GenerateTestMainRequest
-from pants.core.goals.test import TestDebugRequest, TestFieldSet, TestResult, TestSubsystem
+from pants.core.goals.test import (
+    TestDebugAdaptorRequest,
+    TestDebugRequest,
+    TestFieldSet,
+    TestResult,
+    TestSubsystem,
+)
 from pants.core.target_types import FileSourceField
 from pants.core.util_rules.source_files import SourceFiles, SourceFilesRequest
 from pants.engine.fs import EMPTY_FILE_DIGEST, AddPrefix, Digest, MergeDigests
@@ -324,6 +330,13 @@ async def generate_go_tests_debug_request(field_set: GoTestFieldSet) -> TestDebu
     raise NotImplementedError("This is a stub.")
 
 
+@rule
+async def generate_go_tests_debug_adaptor_request(
+    field_set: GoTestFieldSet,
+) -> TestDebugAdaptorRequest:
+    raise NotImplementedError("This is a stub.")
+
+
 def rules():
     return [
         *collect_rules(),

src/python/pants/backend/helm/test/unittest.py

@@ -18,7 +18,13 @@
 )
 from pants.backend.helm.util_rules.chart import HelmChart, HelmChartRequest
 from pants.backend.helm.util_rules.tool import HelmProcess
-from pants.core.goals.test import TestDebugRequest, TestFieldSet, TestResult, TestSubsystem
+from pants.core.goals.test import (
+    TestDebugAdaptorRequest,
+    TestDebugRequest,
+    TestFieldSet,
+    TestResult,
+    TestSubsystem,
+)
 from pants.core.target_types import ResourceSourceField
 from pants.core.util_rules.source_files import SourceFilesRequest
 from pants.core.util_rules.stripped_source_files import StrippedSourceFiles
@@ -142,6 +148,13 @@ async def generate_helm_unittest_debug_request(field_set: HelmUnitTestFieldSet)
     raise NotImplementedError("Can not debug Helm unit tests")
 
 
+@rule
+async def generate_helm_unittest_debug_adaptor_request(
+    field_set: HelmUnitTestFieldSet,
+) -> TestDebugAdaptorRequest:
+    raise NotImplementedError("Can not debug Helm unit tests")
+
+
 def rules():
     return [
         *collect_rules(),

src/python/pants/backend/python/goals/pytest_runner.py

@@ -4,15 +4,17 @@
 import logging
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
-from typing import Optional
+from typing import Optional, Tuple
 
 from pants.backend.python.goals.coverage_py import (
     CoverageConfig,
     CoverageSubsystem,
     PytestCoverageData,
 )
+from pants.backend.python.subsystems.debugpy import DebugPy
 from pants.backend.python.subsystems.pytest import PyTest, PythonTestFieldSet
 from pants.backend.python.subsystems.setup import PythonSetup
+from pants.backend.python.target_types import MainSpecification
 from pants.backend.python.util_rules.interpreter_constraints import InterpreterConstraints
 from pants.backend.python.util_rules.local_dists import LocalDistsPex, LocalDistsPexRequest
 from pants.backend.python.util_rules.pex import Pex, PexRequest, VenvPex, VenvPexProcess
@@ -25,6 +27,7 @@
     BuildPackageDependenciesRequest,
     BuiltPackageDependencies,
     RuntimePackageDependenciesField,
+    TestDebugAdaptorRequest,
     TestDebugRequest,
     TestExtraEnv,
     TestFieldSet,
@@ -58,6 +61,7 @@
 from pants.engine.unions import UnionMembership, UnionRule, union
 from pants.option.global_options import GlobalOptions
 from pants.util.logging import LogLevel
+from pants.util.strutil import softwrap
 
 logger = logging.getLogger()
 
@@ -138,6 +142,9 @@ async def run_all_setup_plugins(
 class TestSetupRequest:
     field_set: PythonTestFieldSet
     is_debug: bool
+    main: Optional[MainSpecification] = None  # Default's to pytest.main
+    prepend_argv: Tuple[str, ...] = ()
+    additional_pexes: Tuple[Pex, ...] = ()
 
 
 @dataclass(frozen=True)
@@ -227,9 +234,9 @@ async def setup_pytest_for_target(
         PexRequest(
             output_filename="pytest_runner.pex",
             interpreter_constraints=interpreter_constraints,
-            main=pytest.main,
+            main=request.main or pytest.main,
             internal_only=True,
-            pex_path=[pytest_pex, requirements_pex, local_dists.pex],
+            pex_path=[*request.additional_pexes, pytest_pex, requirements_pex, local_dists.pex],
         ),
     )
     config_files_get = Get(
@@ -314,7 +321,12 @@ async def setup_pytest_for_target(
         Process,
         VenvPexProcess(
             pytest_runner_pex,
-            argv=(*pytest.args, *coverage_args, *field_set_source_files.files),
+            argv=(
+                *request.prepend_argv,
+                *pytest.args,
+                *coverage_args,
+                *field_set_source_files.files,
+            ),
             extra_env=extra_env,
             input_digest=input_digest,
             output_directories=(_EXTRA_OUTPUT_DIR,),
@@ -381,6 +393,49 @@ async def debug_python_test(field_set: PythonTestFieldSet) -> TestDebugRequest:
     )
 
 
+@rule(desc="Set up debugpy to run an interactive Pytest session", level=LogLevel.DEBUG)
+async def debugpy_python_test(
+    field_set: PythonTestFieldSet,
+    debugpy: DebugPy,
+    pytest: PyTest,
+) -> TestDebugAdaptorRequest:
+    debugpy_pex = await Get(Pex, PexRequest, debugpy.to_pex_request())
+    if pytest.main.spec != "pytest":
+        logger.warn(
+            softwrap(
+                """
+                Ignoring custom [pytest].console_script/entry_point when using --use-debug-adaptor.
+                `debugpy` (Python's Debug Adaptor) doesn't support this use-case yet.
+                """
+            )
+        )
+
+    setup = await Get(
+        TestSetup,
+        TestSetupRequest(
+            field_set,
+            is_debug=True,
+            main=debugpy.main,
+            prepend_argv=(
+                "--listen",
+                f"{debugpy.host}:{debugpy.port}",
+                "--wait-for-client",
+                # @TODO: Techincally we should use `pytest.main`, however `debugpy` doesn't support
+                # launching an entry_point.
+                # https://github.com/microsoft/debugpy/issues/955
+                "-m",
+                "pytest",
+            ),
+            additional_pexes=(debugpy_pex,),
+        ),
+    )
+    return TestDebugAdaptorRequest(
+        InteractiveProcess.from_process(
+            setup.process, forward_signals_to_process=False, restartable=True
+        )
+    )
+
+
 # -----------------------------------------------------------------------------------------
 # `runtime_package_dependencies` plugin
 # -----------------------------------------------------------------------------------------

src/python/pants/backend/python/goals/pytest_runner_integration_test.py

@@ -29,6 +29,7 @@
 )
 from pants.backend.python.util_rules import local_dists, pex_from_targets
 from pants.core.goals.test import (
+    TestDebugAdaptorRequest,
     TestDebugRequest,
     TestResult,
     build_runtime_package_dependencies,
@@ -67,6 +68,7 @@ def rule_runner() -> RuleRunner:
             *setuptools_rules(),
             QueryRule(TestResult, (PythonTestFieldSet,)),
             QueryRule(TestDebugRequest, (PythonTestFieldSet,)),
+            QueryRule(TestDebugAdaptorRequest, (PythonTestFieldSet,)),
         ],
         target_types=[
             PexBinary,
@@ -578,3 +580,37 @@ def is_applicable(tgt_name: str, fp: str) -> bool:
 
     assert not is_applicable("t1", "test_skip_me.py")
     assert is_applicable("t2", "test_foo.py")
+
+
+def test_debug_adaptor_request_argv(rule_runner: RuleRunner) -> None:
+    rule_runner.write_files(
+        {
+            f"{PACKAGE}/test_foo.py": "",
+            f"{PACKAGE}/BUILD": dedent(
+                """\
+                python_tests(name='tests')
+                """
+            ),
+        }
+    )
+
+    args = [
+        "--backend-packages=pants.backend.python",
+        f"--source-root-patterns={SOURCE_ROOT}",
+    ]
+    rule_runner.set_options(args, env_inherit={"PATH", "PYENV_ROOT", "HOME"})
+    tgt = rule_runner.get_target(
+        Address(PACKAGE, target_name="tests", relative_file_path="test_foo.py")
+    )
+    inputs = [PythonTestFieldSet.create(tgt)]
+    request = rule_runner.request(TestDebugAdaptorRequest, inputs)
+    assert request.process is not None
+    assert request.process.argv == (
+        "./pytest_runner.pex_pex_shim.sh",
+        "--listen",
+        "127.0.0.1:5678",
+        "--wait-for-client",
+        "-m",
+        "pytest",
+        "tests/python/pants_test/test_foo.py",
+    )

src/python/pants/backend/python/register.py

@@ -28,7 +28,7 @@
 from pants.backend.python.macros.poetry_requirements import PoetryRequirementsTargetGenerator
 from pants.backend.python.macros.python_artifact import PythonArtifact
 from pants.backend.python.macros.python_requirements import PythonRequirementsTargetGenerator
-from pants.backend.python.subsystems import ipython, pytest, python_native_code, setuptools
+from pants.backend.python.subsystems import debugpy, ipython, pytest, python_native_code, setuptools
 from pants.backend.python.target_types import (
     PexBinariesGeneratorTarget,
     PexBinary,
@@ -61,6 +61,7 @@ def rules():
     return (
         *ancestor_files.rules(),
         *coverage_py.rules(),
+        *debugpy.rules(),
         *dependency_inference_rules.rules(),
         *export.rules(),
         *ipython.rules(),