Add custom SystemModules to bootclasspath to reduce duplication

Adds a library dependency to each of the dummy system modules created
by testing.go so that any changes in the behavior were detected by
the existing tests which were then fixed.

Bug: 141359858
Test: m checkbuild
Change-Id: Id4442f4aa3931ac93049f3367b96a5b49cc075e1

java/java.go

@@ -535,7 +535,9 @@ func (j *Module) deps(ctx android.BottomUpMutatorContext) {
 			ctx.PropertyErrorf("sdk_version",
 				`system_modules is required to be set when sdk_version is "none", did you mean "core_platform"`)
 		} else if *j.deviceProperties.System_modules != "none" {
+			// Add the system modules to both the system modules and bootclasspath.
 			ctx.AddVariationDependencies(nil, systemModulesTag, *j.deviceProperties.System_modules)
+			ctx.AddVariationDependencies(nil, bootClasspathTag, *j.deviceProperties.System_modules)
 		}
 		if ctx.ModuleName() == "android_stubs_current" ||
 			ctx.ModuleName() == "android_system_stubs_current" ||
@@ -848,6 +850,12 @@ func (j *Module) collectDeps(ctx android.ModuleContext) deps {
 			}
 		default:
 			switch tag {
+			case bootClasspathTag:
+				// If a system modules dependency has been added to the bootclasspath
+				// then add its libs to the bootclasspath.
+				sm := module.(*SystemModules)
+				deps.bootClasspath = append(deps.bootClasspath, sm.headerJars...)
+
 			case systemModulesTag:
 				if deps.systemModules != nil {
 					panic("Found two system module dependencies")

java/sdk_test.go

@@ -124,7 +124,7 @@ func TestClasspath(t *testing.T) {
 			name:          "nostdlib system_modules",
 			properties:    `sdk_version: "none", system_modules: "core-platform-api-stubs-system-modules"`,
 			system:        "core-platform-api-stubs-system-modules",
-			bootclasspath: []string{`""`},
+			bootclasspath: []string{"core-platform-api-stubs-system-modules-lib"},
 			classpath:     []string{},
 		},
 		{

java/system_modules.go

@@ -101,6 +101,9 @@ type SystemModules struct {
 
 	properties SystemModulesProperties
 
+	// The aggregated header jars from all jars specified in the libs property.
+	// Used when system module is added as a dependency to bootclasspath.
+	headerJars android.Paths
 	outputDir  android.Path
 	outputDeps android.Paths
 }
@@ -118,6 +121,8 @@ func (system *SystemModules) GenerateAndroidBuildActions(ctx android.ModuleConte
 		jars = append(jars, dep.HeaderJars()...)
 	})
 
+	system.headerJars = jars
+
 	system.outputDir, system.outputDeps = TransformJarsToSystemModules(ctx, "java.base", jars)
 }
 

java/testing.go

@@ -114,7 +114,13 @@ func GatherRequiredDepsForTest() string {
 	for _, extra := range systemModules {
 		bp += fmt.Sprintf(`
 			java_system_modules {
-				name: "%s",
+				name: "%[1]s",
+				libs: ["%[1]s-lib"],
+			}
+			java_library {
+				name: "%[1]s-lib",
+				sdk_version: "none",
+				system_modules: "none",
 			}
 		`, extra)
 	}