[internal] Hook up check to Go (pantsbuild#13322)

This lets you compile a package without needing to run tests or package a binary. 

Note that you can only directly compile a first-party package - to check if a third-party package is buildable, it must be a dependency of a first-party package. Works around pantsbuild#13175.

This does not yet have an optimal UX. It's overly chatty:

```
❯ ./pants check testprojects/src/go::
13:36:38.57 [INFO] Initializing scheduler...
13:36:39.20 [INFO] Scheduler initialized.
13:36:39.71 [ERROR] Completed: pants.backend.go.goals.check.check_go - go failed (exit code 1).
Partition #1 - github.com/pantsbuild/pants/testprojects/src/go/pants_test:
./testprojects/src/go/pants_test/foo.go:3:1: syntax error: non-declaration statement outside function body

Partition #2 - github.com/pantsbuild/pants/testprojects/src/go/pants_test/bar:



𐄂 go failed.
```

We also should be streaming the result of each compilation as it happens, which has an added benefit of that output happening when compilation happens as a side effect of `run`, `package`, and `test`. Those fixes will be in a followup.

[ci skip-rust]
[ci skip-build-wheels]

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

@@ -2,7 +2,7 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 from pants.backend.go import target_type_rules
-from pants.backend.go.goals import package_binary, run_binary, tailor, test
+from pants.backend.go.goals import check, package_binary, run_binary, tailor, test
 from pants.backend.go.lint import fmt
 from pants.backend.go.lint.gofmt import skip_field as gofmt_skip_field
 from pants.backend.go.lint.gofmt.rules import rules as gofmt_rules
@@ -34,6 +34,7 @@ def rules():
     return [
         *assembly.rules(),
         *build_pkg.rules(),
+        *check.rules(),
         *third_party_pkg.rules(),
         *golang.rules(),
         *import_analysis.rules(),

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

@@ -0,0 +1,76 @@
+# Copyright 2021 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+from dataclasses import dataclass
+from typing import cast
+
+from pants.backend.go.target_types import GoFirstPartyPackageSourcesField
+from pants.backend.go.util_rules.build_pkg import (
+    BuildGoPackageRequest,
+    BuildGoPackageTargetRequest,
+    FallibleBuildGoPackageRequest,
+    FallibleBuiltGoPackage,
+)
+from pants.core.goals.check import CheckRequest, CheckResult, CheckResults
+from pants.engine.rules import Get, MultiGet, collect_rules, rule
+from pants.engine.target import FieldSet
+from pants.engine.unions import UnionRule
+
+
+@dataclass(frozen=True)
+class GoCheckFieldSet(FieldSet):
+    required_fields = (GoFirstPartyPackageSourcesField,)
+
+    sources: GoFirstPartyPackageSourcesField
+
+
+class GoCheckRequest(CheckRequest):
+    field_set_type = GoCheckFieldSet
+
+
+@rule
+async def check_go(request: GoCheckRequest) -> CheckResults:
+    build_requests = await MultiGet(
+        Get(FallibleBuildGoPackageRequest, BuildGoPackageTargetRequest(field_set.address))
+        for field_set in request.field_sets
+    )
+    invalid_requests = []
+    valid_requests = []
+    for fallible_request in build_requests:
+        if fallible_request.request is None:
+            invalid_requests.append(fallible_request)
+        else:
+            valid_requests.append(fallible_request.request)
+
+    build_results = await MultiGet(
+        Get(FallibleBuiltGoPackage, BuildGoPackageRequest, request) for request in valid_requests
+    )
+
+    # TODO: Update `build_pkg.py` to use streaming workunits to log compilation results, which has
+    #  the benefit of other contexts like `test.py` using it. Switch this to only preserve the
+    #  exit code.
+    check_results = [
+        *(
+            CheckResult(
+                result.exit_code,
+                "",
+                cast(str, result.stderr),
+                partition_description=result.import_path,
+            )
+            for result in invalid_requests
+        ),
+        *(
+            CheckResult(
+                result.exit_code,
+                result.stdout or "",
+                result.stderr or "",
+                partition_description=result.import_path,
+            )
+            for result in build_results
+        ),
+    ]
+    return CheckResults(check_results, checker_name="go")
+
+
+def rules():
+    return [*collect_rules(), UnionRule(CheckRequest, GoCheckRequest)]

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

@@ -0,0 +1,85 @@
+# Copyright 2021 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+from __future__ import annotations
+
+from textwrap import dedent
+
+import pytest
+
+from pants.backend.go import target_type_rules
+from pants.backend.go.goals import check
+from pants.backend.go.goals.check import GoCheckFieldSet, GoCheckRequest
+from pants.backend.go.target_types import GoModTarget
+from pants.backend.go.util_rules import (
+    assembly,
+    build_pkg,
+    first_party_pkg,
+    go_mod,
+    import_analysis,
+    sdk,
+    third_party_pkg,
+)
+from pants.core.goals.check import CheckResult, CheckResults
+from pants.engine.addresses import Address
+from pants.testutil.rule_runner import QueryRule, RuleRunner
+
+
+@pytest.fixture
+def rule_runner() -> RuleRunner:
+    rule_runner = RuleRunner(
+        rules=[
+            *check.rules(),
+            *sdk.rules(),
+            *assembly.rules(),
+            *build_pkg.rules(),
+            *import_analysis.rules(),
+            *go_mod.rules(),
+            *first_party_pkg.rules(),
+            *third_party_pkg.rules(),
+            *target_type_rules.rules(),
+            QueryRule(CheckResults, [GoCheckRequest]),
+        ],
+        target_types=[GoModTarget],
+    )
+    rule_runner.set_options([], env_inherit={"PATH"})
+    return rule_runner
+
+
+def test_check(rule_runner: RuleRunner) -> None:
+    rule_runner.write_files(
+        {
+            "go.mod": dedent(
+                """\
+                module example.com/greeter
+                go 1.17
+                """
+            ),
+            "bad/f.go": "invalid!!!",
+            "good/f.go": dedent(
+                """\
+                package greeter
+
+                import "fmt"
+
+                func Hello() {
+                    fmt.Println("Hello world!")
+                }
+                """
+            ),
+            "BUILD": "go_mod(name='mod')",
+        }
+    )
+    targets = [
+        rule_runner.get_target(Address("", target_name="mod", generated_name="./bad")),
+        rule_runner.get_target(Address("", target_name="mod", generated_name="./good")),
+    ]
+    results = rule_runner.request(
+        CheckResults, [GoCheckRequest(GoCheckFieldSet.create(tgt) for tgt in targets)]
+    ).results
+    assert set(results) == {
+        CheckResult(0, "", "", "example.com/greeter/good"),
+        CheckResult(
+            1, "", "bad/f.go:1:1: expected 'package', found invalid\n", "example.com/greeter/bad"
+        ),
+    }