Merge "Provide reason for unconverted bp2build modules"

android/Android.bp

@@ -19,6 +19,7 @@ bootstrap_go_package {
         "soong-shared",
         "soong-starlark",
         "soong-starlark-format",
+        "soong-ui-bp2build_metrics_proto",
         "soong-ui-metrics_proto",
         "soong-android-allowlists",
 

android/bazel.go

@@ -17,8 +17,10 @@ package android
 import (
 	"bufio"
 	"errors"
+	"fmt"
 	"strings"
 
+	"android/soong/ui/metrics/bp2build_metrics_proto"
 	"github.com/google/blueprint"
 	"github.com/google/blueprint/proptools"
 
@@ -73,6 +75,21 @@ type BazelConversionStatus struct {
 
 	// MissingBp2buildDep stores the module names of direct dependency that were not found
 	MissingDeps []string `blueprint:"mutated"`
+
+	// If non-nil, indicates that the module could not be converted successfully
+	// with bp2build. This will describe the reason the module could not be converted.
+	UnconvertedReason *UnconvertedReason
+}
+
+// The reason a module could not be converted to a BUILD target via bp2build.
+// This should match bp2build_metrics_proto.UnconvertedReason, but omits private
+// proto-related fields that prevent copying this struct.
+type UnconvertedReason struct {
+	// Should correspond to a valid value in bp2build_metrics_proto.UnconvertedReasonType.
+	// A raw int is used here instead, because blueprint logic requires that all transitive
+	// fields of module definitions be primitives.
+	ReasonType int
+	Detail     string
 }
 
 type BazelModuleProperties struct {
@@ -137,6 +154,12 @@ type Bazelable interface {
 	GetBazelLabel(ctx BazelConversionPathContext, module blueprint.Module) string
 	ShouldConvertWithBp2build(ctx BazelConversionContext) bool
 	shouldConvertWithBp2build(ctx bazelOtherModuleContext, module blueprint.Module) bool
+
+	// ConvertWithBp2build either converts the module to a Bazel build target or
+	// declares the module as unconvertible (for logging and metrics).
+	// Modules must implement this function to be bp2build convertible. The function
+	// must either create at least one Bazel target module (using ctx.CreateBazelTargetModule or
+	// its related functions), or declare itself unconvertible using ctx.MarkBp2buildUnconvertible.
 	ConvertWithBp2build(ctx TopDownMutatorContext)
 
 	// namespacedVariableProps is a map from a soong config variable namespace
@@ -232,7 +255,7 @@ func (b *BazelModuleBase) GetBazelLabel(ctx BazelConversionPathContext, module b
 	if b.ShouldConvertWithBp2build(ctx) {
 		return bp2buildModuleLabel(ctx, module)
 	}
-	return "" // no label for unconverted module
+	panic(fmt.Errorf("requested non-existent label for module ", module.Name()))
 }
 
 type Bp2BuildConversionAllowlist struct {
@@ -533,22 +556,32 @@ func bp2buildDefaultTrueRecursively(packagePath string, config allowlists.Bp2Bui
 }
 
 func registerBp2buildConversionMutator(ctx RegisterMutatorsContext) {
-	ctx.TopDown("bp2build_conversion", convertWithBp2build).Parallel()
+	ctx.TopDown("bp2build_conversion", bp2buildConversionMutator).Parallel()
 }
 
-func convertWithBp2build(ctx TopDownMutatorContext) {
+func bp2buildConversionMutator(ctx TopDownMutatorContext) {
 	if ctx.Config().HasBazelBuildTargetInSource(ctx) {
 		// Defer to the BUILD target. Generating an additional target would
 		// cause a BUILD file conflict.
+		ctx.MarkBp2buildUnconvertible(bp2build_metrics_proto.UnconvertedReasonType_DEFINED_IN_BUILD_FILE, "")
 		return
 	}
 
 	bModule, ok := ctx.Module().(Bazelable)
-	if !ok || !bModule.shouldConvertWithBp2build(ctx, ctx.Module()) {
+	if !ok {
+		ctx.MarkBp2buildUnconvertible(bp2build_metrics_proto.UnconvertedReasonType_TYPE_UNSUPPORTED, "")
+		return
+	}
+	// TODO: b/285631638 - Differentiate between denylisted modules and missing bp2build capabilities.
+	if !bModule.shouldConvertWithBp2build(ctx, ctx.Module()) {
+		ctx.MarkBp2buildUnconvertible(bp2build_metrics_proto.UnconvertedReasonType_UNSUPPORTED, "")
 		return
 	}
-
 	bModule.ConvertWithBp2build(ctx)
+
+	if !ctx.Module().base().IsConvertedByBp2build() && ctx.Module().base().GetUnconvertedReason() == nil {
+		panic(fmt.Errorf("illegal bp2build invariant: module '%s' was neither converted nor marked unconvertible", ctx.ModuleName()))
+	}
 }
 
 func registerApiBp2buildConversionMutator(ctx RegisterMutatorsContext) {

android/defaults.go

@@ -17,6 +17,7 @@ package android
 import (
 	"reflect"
 
+	"android/soong/ui/metrics/bp2build_metrics_proto"
 	"github.com/google/blueprint"
 	"github.com/google/blueprint/proptools"
 )
@@ -179,7 +180,10 @@ func (d *DefaultsModuleBase) GenerateAndroidBuildActions(ctx ModuleContext) {}
 
 // ConvertWithBp2build to fulfill Bazelable interface; however, at this time defaults module are
 // *NOT* converted with bp2build
-func (defaultable *DefaultsModuleBase) ConvertWithBp2build(ctx TopDownMutatorContext) {}
+func (defaultable *DefaultsModuleBase) ConvertWithBp2build(ctx TopDownMutatorContext) {
+	// Defaults types are never convertible.
+	ctx.MarkBp2buildUnconvertible(bp2build_metrics_proto.UnconvertedReasonType_TYPE_UNSUPPORTED, "")
+}
 
 func InitDefaultsModule(module DefaultsModule) {
 	commonProperties := &commonProperties{}

android/filegroup.go

@@ -21,6 +21,7 @@ import (
 
 	"android/soong/bazel"
 	"android/soong/bazel/cquery"
+	"android/soong/ui/metrics/bp2build_metrics_proto"
 
 	"github.com/google/blueprint"
 )
@@ -111,6 +112,7 @@ func (fg *fileGroup) ConvertWithBp2build(ctx TopDownMutatorContext) {
 			if len(srcs.Value.Includes) > 1 {
 				ctx.ModuleErrorf("filegroup '%s' cannot contain a file with the same name", fg.Name())
 			}
+			ctx.MarkBp2buildUnconvertible(bp2build_metrics_proto.UnconvertedReasonType_SRC_NAME_COLLISION, "")
 			return
 		}
 	}

android/module.go

@@ -30,6 +30,7 @@ import (
 	"text/scanner"
 
 	"android/soong/bazel"
+	"android/soong/ui/metrics/bp2build_metrics_proto"
 
 	"github.com/google/blueprint"
 	"github.com/google/blueprint/proptools"
@@ -566,6 +567,8 @@ type Module interface {
 
 	// IsConvertedByBp2build returns whether this module was converted via bp2build
 	IsConvertedByBp2build() bool
+	GetUnconvertedReason() *UnconvertedReason
+
 	// Bp2buildTargets returns the target(s) generated for Bazel via bp2build for this module
 	Bp2buildTargets() []bp2buildInfo
 	GetUnconvertedBp2buildDeps() []string
@@ -1596,14 +1599,31 @@ func (b bp2buildInfo) BazelAttributes() []interface{} {
 }
 
 func (m *ModuleBase) addBp2buildInfo(info bp2buildInfo) {
+	if m.commonProperties.BazelConversionStatus.UnconvertedReason != nil {
+		panic(fmt.Errorf("bp2build: module '%s' marked unconvertible and also is converted", m.Name()))
+	}
 	m.commonProperties.BazelConversionStatus.Bp2buildInfo = append(m.commonProperties.BazelConversionStatus.Bp2buildInfo, info)
 }
 
+func (m *ModuleBase) setBp2buildUnconvertible(reasonType bp2build_metrics_proto.UnconvertedReasonType, detail string) {
+	if len(m.commonProperties.BazelConversionStatus.Bp2buildInfo) > 0 {
+		panic(fmt.Errorf("bp2build: module '%s' marked unconvertible and also is converted", m.Name()))
+	}
+	m.commonProperties.BazelConversionStatus.UnconvertedReason = &UnconvertedReason{
+		ReasonType: int(reasonType),
+		Detail:     detail,
+	}
+}
+
 // IsConvertedByBp2build returns whether this module was converted via bp2build.
 func (m *ModuleBase) IsConvertedByBp2build() bool {
 	return len(m.commonProperties.BazelConversionStatus.Bp2buildInfo) > 0
 }
 
+func (m *ModuleBase) GetUnconvertedReason() *UnconvertedReason {
+	return m.commonProperties.BazelConversionStatus.UnconvertedReason
+}
+
 // Bp2buildTargets returns the Bazel targets bp2build generated for this module.
 func (m *ModuleBase) Bp2buildTargets() []bp2buildInfo {
 	return m.commonProperties.BazelConversionStatus.Bp2buildInfo

android/mutator.go

@@ -16,6 +16,7 @@ package android
 
 import (
 	"android/soong/bazel"
+	"android/soong/ui/metrics/bp2build_metrics_proto"
 
 	"github.com/google/blueprint"
 )
@@ -271,6 +272,10 @@ type TopDownMutatorContext interface {
 	// any platform for which this bool attribute is false.
 	CreateBazelTargetModuleWithRestrictions(bazel.BazelTargetModuleProperties, CommonAttributes, interface{}, bazel.BoolAttribute)
 
+	// MarkBp2buildUnconvertible registers the current module as "unconvertible to bp2build" for the
+	// given reason.
+	MarkBp2buildUnconvertible(reasonType bp2build_metrics_proto.UnconvertedReasonType, detail string)
+
 	// CreateBazelTargetAliasInDir creates an alias definition in `dir` directory.
 	// This function can be used to create alias definitions in a directory that is different
 	// from the directory of the visited Soong module.
@@ -718,6 +723,12 @@ func (t *topDownMutatorContext) CreateBazelTargetModuleWithRestrictions(
 	t.createBazelTargetModule(bazelProps, commonAttrs, attrs, enabledProperty)
 }
 
+func (t *topDownMutatorContext) MarkBp2buildUnconvertible(
+	reasonType bp2build_metrics_proto.UnconvertedReasonType, detail string) {
+	mod := t.Module()
+	mod.base().setBp2buildUnconvertible(reasonType, detail)
+}
+
 var (
 	bazelAliasModuleProperties = bazel.BazelTargetModuleProperties{
 		Rule_class: "alias",