go: add debug goal to show package analysis (#16429)

Add a `go-show-package-analysis` debug goal to display package analysis for first-party and third-party Go packages. The goal is made available if the user enables the `pants.backend.experimental.go.debug_goals` backend.

src/python/pants/backend/experimental/go/debug_goals/BUILD

@@ -0,0 +1,4 @@
+# Copyright 2021 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+python_sources()

src/python/pants/backend/experimental/go/debug_goals/register.py

@@ -0,0 +1,17 @@
+# Copyright 2022 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+from pants.backend.experimental.go.register import rules as go_backend_rules
+from pants.backend.experimental.go.register import target_types as go_target_types_func
+from pants.backend.go.goals import debug_goals
+
+
+def target_types():
+    return go_target_types_func()
+
+
+def rules():
+    return (
+        *debug_goals.rules(),
+        *go_backend_rules(),
+    )

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

@@ -0,0 +1,87 @@
+# Copyright 2022 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+from __future__ import annotations
+
+from pants.backend.go.target_types import (
+    GoImportPathField,
+    GoPackageSourcesField,
+    GoThirdPartyPackageDependenciesField,
+)
+from pants.backend.go.util_rules import first_party_pkg, third_party_pkg
+from pants.backend.go.util_rules.first_party_pkg import (
+    FallibleFirstPartyPkgAnalysis,
+    FirstPartyPkgAnalysisRequest,
+)
+from pants.backend.go.util_rules.go_mod import GoModInfo, GoModInfoRequest
+from pants.backend.go.util_rules.third_party_pkg import (
+    ThirdPartyPkgAnalysis,
+    ThirdPartyPkgAnalysisRequest,
+)
+from pants.engine.console import Console
+from pants.engine.goal import Goal, GoalSubsystem
+from pants.engine.internals.selectors import Get, MultiGet
+from pants.engine.rules import collect_rules, goal_rule
+from pants.engine.target import Targets
+
+
+class ShowGoPackageAnalysisSubsystem(GoalSubsystem):
+    name = "go-show-package-analysis"
+    help = "Show the package analysis for Go package targets."
+
+
+class ShowGoPackageAnalysis(Goal):
+    subsystem_cls = ShowGoPackageAnalysisSubsystem
+
+
+@goal_rule
+async def go_show_package_analysis(targets: Targets, console: Console) -> ShowGoPackageAnalysis:
+    first_party_analysis_gets = []
+    third_party_analysis_gets = []
+
+    for target in targets:
+        if target.has_field(GoPackageSourcesField):
+            first_party_analysis_gets.append(
+                Get(FallibleFirstPartyPkgAnalysis, FirstPartyPkgAnalysisRequest(target.address))
+            )
+        elif target.has_field(GoThirdPartyPackageDependenciesField):
+            import_path = target[GoImportPathField].value
+            go_mod_address = target.address.maybe_convert_to_target_generator()
+            go_mod_info = await Get(GoModInfo, GoModInfoRequest(go_mod_address))
+            third_party_analysis_gets.append(
+                Get(
+                    ThirdPartyPkgAnalysis,
+                    ThirdPartyPkgAnalysisRequest(
+                        import_path, go_mod_info.digest, go_mod_info.mod_path
+                    ),
+                )
+            )
+
+    first_party_analysis_results = await MultiGet(first_party_analysis_gets)
+    third_party_analysis_results = await MultiGet(third_party_analysis_gets)
+
+    for first_party_analysis_result in first_party_analysis_results:
+        if first_party_analysis_result.analysis:
+            console.write_stdout(str(first_party_analysis_result.analysis) + "\n")
+        else:
+            console.write_stdout(
+                f"Error for {first_party_analysis_result.import_path}: {first_party_analysis_result.stderr}\n"
+            )
+
+    for third_party_analysis in third_party_analysis_results:
+        if third_party_analysis.error:
+            console.write_stdout(
+                f"Error for {third_party_analysis.import_path}: {third_party_analysis.error}\n"
+            )
+        else:
+            console.write_stdout(str(third_party_analysis) + "\n")
+
+    return ShowGoPackageAnalysis(exit_code=0)
+
+
+def rules():
+    return (
+        *collect_rules(),
+        *first_party_pkg.rules(),
+        *third_party_pkg.rules(),
+    )