1 files changed, 19 insertions, 28 deletions

diff --git a/android/makevars.go b/android/makevars.go
index 3ca7792d4..f78439596 100644
--- a/android/makevars.go
+++ b/android/makevars.go
@@ -139,15 +139,24 @@ type SingletonMakeVarsProvider interface {
 	MakeVars(ctx MakeVarsContext)
 }
 
-// registerSingletonMakeVarsProvider adds a singleton that implements SingletonMakeVarsProvider to the list of
-// MakeVarsProviders to run.
-func registerSingletonMakeVarsProvider(singleton SingletonMakeVarsProvider) {
-	singletonMakeVarsProviders = append(singletonMakeVarsProviders,
-		makeVarsProvider{pctx, SingletonmakeVarsProviderAdapter(singleton)})
+var singletonMakeVarsProvidersKey = NewOnceKey("singletonMakeVarsProvidersKey")
+
+// registerSingletonMakeVarsProvider adds a singleton that implements SingletonMakeVarsProvider to
+// the list of MakeVarsProviders to run.
+func registerSingletonMakeVarsProvider(config Config, singleton SingletonMakeVarsProvider) {
+	// Singletons are registered on the Context and may be different between different Contexts,
+	// for example when running multiple tests.  Store the SingletonMakeVarsProviders in the
+	// Config so they are attached to the Context.
+	singletonMakeVarsProviders := config.Once(singletonMakeVarsProvidersKey, func() interface{} {
+		return &[]makeVarsProvider{}
+	}).(*[]makeVarsProvider)
+
+	*singletonMakeVarsProviders = append(*singletonMakeVarsProviders,
+		makeVarsProvider{pctx, singletonMakeVarsProviderAdapter(singleton)})
 }
 
-// SingletonmakeVarsProviderAdapter converts a SingletonMakeVarsProvider to a MakeVarsProvider.
-func SingletonmakeVarsProviderAdapter(singleton SingletonMakeVarsProvider) MakeVarsProvider {
+// singletonMakeVarsProviderAdapter converts a SingletonMakeVarsProvider to a MakeVarsProvider.
+func singletonMakeVarsProviderAdapter(singleton SingletonMakeVarsProvider) MakeVarsProvider {
 	return func(ctx MakeVarsContext) { singleton.MakeVars(ctx) }
 }
 
@@ -175,9 +184,6 @@ type makeVarsProvider struct {
 // Collection of makevars providers that are registered in init() methods.
 var makeVarsInitProviders []makeVarsProvider
 
-// Collection of singleton makevars providers that are not registered as part of init() methods.
-var singletonMakeVarsProviders []makeVarsProvider
-
 type makeVarsContext struct {
 	SingletonContext
 	config  Config
@@ -224,20 +230,11 @@ func (s *makeVarsSingleton) GenerateBuildActions(ctx SingletonContext) {
 	var vars []makeVarsVariable
 	var dists []dist
 	var phonies []phony
-	for _, provider := range append(makeVarsInitProviders) {
-		mctx := &makeVarsContext{
-			SingletonContext: ctx,
-			pctx:             provider.pctx,
-		}
 
-		provider.call(mctx)
+	providers := append([]makeVarsProvider(nil), makeVarsInitProviders...)
+	providers = append(providers, *ctx.Config().Get(singletonMakeVarsProvidersKey).(*[]makeVarsProvider)...)
 
-		vars = append(vars, mctx.vars...)
-		phonies = append(phonies, mctx.phonies...)
-		dists = append(dists, mctx.dists...)
-	}
-
-	for _, provider := range append(singletonMakeVarsProviders) {
+	for _, provider := range providers {
 		mctx := &makeVarsContext{
 			SingletonContext: ctx,
 			pctx:             provider.pctx,
@@ -250,12 +247,6 @@ func (s *makeVarsSingleton) GenerateBuildActions(ctx SingletonContext) {
 		dists = append(dists, mctx.dists...)
 	}
 
-	// Clear singleton makevars providers after use. Since these are in-memory
-	// singletons, this ensures state is reset if the build tree is processed
-	// multiple times.
-	// TODO(cparsons): Clean up makeVarsProviders to be part of the context.
-	singletonMakeVarsProviders = nil
-
 	ctx.VisitAllModules(func(m Module) {
 		if provider, ok := m.(ModuleMakeVarsProvider); ok && m.Enabled() {
 			mctx := &makeVarsContext{