Correct link type for module stubs

Module stubs compile against module_current, so any module depending on
them had to compile against module_current (or broader) too. Treat them
as the API surface the stubs are for.

Bug: 157010342
Test: m
Change-Id: I49b9082dc1b5afe6c22e94126e574dd8061f0f39

java/java.go

@@ -843,6 +843,10 @@ func (m *Module) getLinkType(name string) (ret linkType, stubs bool) {
 		return javaSystem, true
 	}
 
+	if stub, linkType := moduleStubLinkType(name); stub {
+		return linkType, true
+	}
+
 	ver := m.sdkVersion()
 	switch ver.kind {
 	case sdkCore:

java/sdk_library.go

@@ -1224,6 +1224,24 @@ func (s *frameworkModulesNamingScheme) apiModuleName(scope *apiScope, baseName s
 
 var _ sdkLibraryComponentNamingScheme = (*frameworkModulesNamingScheme)(nil)
 
+func moduleStubLinkType(name string) (stub bool, ret linkType) {
+	// This suffix-based approach is fragile and could potentially mis-trigger.
+	// TODO(b/155164730): Clean this up when modules no longer reference sdk_lib stubs directly.
+	if strings.HasSuffix(name, ".stubs.public") || strings.HasSuffix(name, "-stubs-publicapi") {
+		return true, javaSdk
+	}
+	if strings.HasSuffix(name, ".stubs.system") || strings.HasSuffix(name, "-stubs-systemapi") {
+		return true, javaSystem
+	}
+	if strings.HasSuffix(name, ".stubs.module_lib") || strings.HasSuffix(name, "-stubs-module_libs_api") {
+		return true, javaModule
+	}
+	if strings.HasSuffix(name, ".stubs.test") {
+		return true, javaSystem
+	}
+	return false, javaPlatform
+}
+
 // java_sdk_library is a special Java library that provides optional platform APIs to apps.
 // In practice, it can be viewed as a combination of several modules: 1) stubs library that clients
 // are linked against to, 2) droiddoc module that internally generates API stubs source files,