bp2build: add python_binary_host converter.

This CL adds a simple python_binary_host to native py_binary converter
for standalone modules that don't depend on libs. It also adds support
for the conditional py2/py3 build target based on the version prop.

Test: milestone-2/demo.sh full
Test: bazel query 'kind("py_binary rule", //bionic/...)'
Test: bazel run //bionic/libc/tools:genfunctosyscallnrs
Test: bazel run //bionic/libc/tools:genseccomp
Test: go tests
Fixes: 182236395
Change-Id: Ibe5ec6cd0dc12a61b3a449a8c723d80b891fae42

bp2build/Android.bp

@@ -19,6 +19,7 @@ bootstrap_go_package {
         "soong-bazel",
         "soong-cc",
         "soong-genrule",
+        "soong-python",
         "soong-sh",
     ],
     testSrcs: [
@@ -27,6 +28,7 @@ bootstrap_go_package {
         "cc_library_headers_conversion_test.go",
         "cc_object_conversion_test.go",
         "conversion_test.go",
+        "python_binary_conversion_test.go",
         "sh_conversion_test.go",
         "testing.go",
     ],

bp2build/python_binary_conversion_test.go

@@ -0,0 +1,170 @@
+package bp2build
+
+import (
+	"android/soong/android"
+	"android/soong/python"
+	"fmt"
+	"strings"
+	"testing"
+)
+
+func TestPythonBinaryHost(t *testing.T) {
+	testCases := []struct {
+		description                        string
+		moduleTypeUnderTest                string
+		moduleTypeUnderTestFactory         android.ModuleFactory
+		moduleTypeUnderTestBp2BuildMutator func(android.TopDownMutatorContext)
+		blueprint                          string
+		expectedBazelTargets               []string
+		filesystem                         map[string]string
+	}{
+		{
+			description:                        "simple python_binary_host converts to a native py_binary",
+			moduleTypeUnderTest:                "python_binary_host",
+			moduleTypeUnderTestFactory:         python.PythonBinaryHostFactory,
+			moduleTypeUnderTestBp2BuildMutator: python.PythonBinaryBp2Build,
+			filesystem: map[string]string{
+				"a.py":           "",
+				"b/c.py":         "",
+				"b/d.py":         "",
+				"b/e.py":         "",
+				"files/data.txt": "",
+			},
+			blueprint: `python_binary_host {
+    name: "foo",
+    main: "a.py",
+    srcs: [
+        "**/*.py"
+    ],
+    exclude_srcs: [
+        "b/e.py"
+    ],
+    data: [
+        "files/data.txt",
+    ],
+
+    bazel_module: { bp2build_available: true },
+}
+`,
+			expectedBazelTargets: []string{`py_binary(
+    name = "foo",
+    data = [
+        "files/data.txt",
+    ],
+    main = "a.py",
+    srcs = [
+        "a.py",
+        "b/c.py",
+        "b/d.py",
+    ],
+)`,
+			},
+		},
+		{
+			description:                        "py2 python_binary_host",
+			moduleTypeUnderTest:                "python_binary_host",
+			moduleTypeUnderTestFactory:         python.PythonBinaryHostFactory,
+			moduleTypeUnderTestBp2BuildMutator: python.PythonBinaryBp2Build,
+			blueprint: `python_binary_host {
+    name: "foo",
+    srcs: ["a.py"],
+    version: {
+        py2: {
+            enabled: true,
+        },
+        py3: {
+            enabled: false,
+        },
+    },
+
+    bazel_module: { bp2build_available: true },
+}
+`,
+			expectedBazelTargets: []string{`py_binary(
+    name = "foo",
+    python_version = "PY2",
+    srcs = [
+        "a.py",
+    ],
+)`,
+			},
+		},
+		{
+			description:                        "py3 python_binary_host",
+			moduleTypeUnderTest:                "python_binary_host",
+			moduleTypeUnderTestFactory:         python.PythonBinaryHostFactory,
+			moduleTypeUnderTestBp2BuildMutator: python.PythonBinaryBp2Build,
+			blueprint: `python_binary_host {
+    name: "foo",
+    srcs: ["a.py"],
+    version: {
+        py2: {
+            enabled: false,
+        },
+        py3: {
+            enabled: true,
+        },
+    },
+
+    bazel_module: { bp2build_available: true },
+}
+`,
+			expectedBazelTargets: []string{
+				// python_version is PY3 by default.
+				`py_binary(
+    name = "foo",
+    srcs = [
+        "a.py",
+    ],
+)`,
+			},
+		},
+	}
+
+	dir := "."
+	for _, testCase := range testCases {
+		filesystem := make(map[string][]byte)
+		toParse := []string{
+			"Android.bp",
+		}
+		for f, content := range testCase.filesystem {
+			if strings.HasSuffix(f, "Android.bp") {
+				toParse = append(toParse, f)
+			}
+			filesystem[f] = []byte(content)
+		}
+		config := android.TestConfig(buildDir, nil, testCase.blueprint, filesystem)
+		ctx := android.NewTestContext(config)
+
+		ctx.RegisterModuleType(testCase.moduleTypeUnderTest, testCase.moduleTypeUnderTestFactory)
+		ctx.RegisterBp2BuildMutator(testCase.moduleTypeUnderTest, testCase.moduleTypeUnderTestBp2BuildMutator)
+		ctx.RegisterForBazelConversion()
+
+		_, errs := ctx.ParseFileList(dir, toParse)
+		if Errored(t, testCase.description, errs) {
+			continue
+		}
+		_, errs = ctx.ResolveDependencies(config)
+		if Errored(t, testCase.description, errs) {
+			continue
+		}
+
+		codegenCtx := NewCodegenContext(config, *ctx.Context, Bp2Build)
+		bazelTargets := generateBazelTargetsForDir(codegenCtx, dir)
+		if actualCount, expectedCount := len(bazelTargets), len(testCase.expectedBazelTargets); actualCount != expectedCount {
+			fmt.Println(bazelTargets)
+			t.Errorf("%s: Expected %d bazel target, got %d", testCase.description, expectedCount, actualCount)
+		} else {
+			for i, target := range bazelTargets {
+				if w, g := testCase.expectedBazelTargets[i], target.content; w != g {
+					t.Errorf(
+						"%s: Expected generated Bazel target to be '%s', got '%s'",
+						testCase.description,
+						w,
+						g,
+					)
+				}
+			}
+		}
+	}
+}

python/binary.go

@@ -20,10 +20,92 @@ import (
 	"fmt"
 
 	"android/soong/android"
+	"android/soong/bazel"
+
+	"github.com/google/blueprint/proptools"
 )
 
 func init() {
 	android.RegisterModuleType("python_binary_host", PythonBinaryHostFactory)
+	android.RegisterBp2BuildMutator("python_binary_host", PythonBinaryBp2Build)
+}
+
+type bazelPythonBinaryAttributes struct {
+	Main           string
+	Srcs           bazel.LabelList
+	Data           bazel.LabelList
+	Python_version string
+}
+
+type bazelPythonBinary struct {
+	android.BazelTargetModuleBase
+	bazelPythonBinaryAttributes
+}
+
+func BazelPythonBinaryFactory() android.Module {
+	module := &bazelPythonBinary{}
+	module.AddProperties(&module.bazelPythonBinaryAttributes)
+	android.InitBazelTargetModule(module)
+	return module
+}
+
+func (m *bazelPythonBinary) Name() string {
+	return m.BaseModuleName()
+}
+
+func (m *bazelPythonBinary) GenerateAndroidBuildActions(ctx android.ModuleContext) {}
+
+func PythonBinaryBp2Build(ctx android.TopDownMutatorContext) {
+	m, ok := ctx.Module().(*Module)
+	if !ok || !m.ConvertWithBp2build() {
+		return
+	}
+
+	// a Module can be something other than a python_binary_host
+	if ctx.ModuleType() != "python_binary_host" {
+		return
+	}
+
+	var main string
+	for _, propIntf := range m.GetProperties() {
+		if props, ok := propIntf.(*BinaryProperties); ok {
+			// main is optional.
+			if props.Main != nil {
+				main = *props.Main
+				break
+			}
+		}
+	}
+	// TODO(b/182306917): this doesn't fully handle all nested props versioned
+	// by the python version, which would have been handled by the version split
+	// mutator. This is sufficient for very simple python_binary_host modules
+	// under Bionic.
+	py3Enabled := proptools.BoolDefault(m.properties.Version.Py3.Enabled, false)
+	py2Enabled := proptools.BoolDefault(m.properties.Version.Py2.Enabled, false)
+	var python_version string
+	if py3Enabled && py2Enabled {
+		panic(fmt.Errorf(
+			"error for '%s' module: bp2build's python_binary_host converter does not support "+
+				"converting a module that is enabled for both Python 2 and 3 at the same time.", m.Name()))
+	} else if py2Enabled {
+		python_version = "PY2"
+	} else {
+		// do nothing, since python_version defaults to PY3.
+	}
+
+	attrs := &bazelPythonBinaryAttributes{
+		Main:           main,
+		Srcs:           android.BazelLabelForModuleSrcExcludes(ctx, m.properties.Srcs, m.properties.Exclude_srcs),
+		Data:           android.BazelLabelForModuleSrc(ctx, m.properties.Data),
+		Python_version: python_version,
+	}
+
+	props := bazel.BazelTargetModuleProperties{
+		// Use the native py_binary rule.
+		Rule_class: "py_binary",
+	}
+
+	ctx.CreateBazelTargetModule(BazelPythonBinaryFactory, m.Name(), props, attrs)
 }
 
 type BinaryProperties struct {
@@ -81,6 +163,8 @@ func NewBinary(hod android.HostOrDeviceSupported) (*Module, *binaryDecorator) {
 func PythonBinaryHostFactory() android.Module {
 	module, _ := NewBinary(android.HostSupported)
 
+	android.InitBazelModule(module)
+
 	return module.init()
 }
 

python/python.go

@@ -125,6 +125,7 @@ type pathMapping struct {
 type Module struct {
 	android.ModuleBase
 	android.DefaultableModuleBase
+	android.BazelModuleBase
 
 	properties      BaseProperties
 	protoProperties android.ProtoProperties