Make android_app.stem overridable

override_android_app can set "stem" property to set the APK name.

Bug: 193504286
Test: m (soong test)
Change-Id: I9ad66ea28bd1b030cb2c588d1f070d72e62ab1c7

java/app.go

@@ -1163,7 +1163,10 @@ func (i *OverrideAndroidApp) GenerateAndroidBuildActions(_ android.ModuleContext
 // some of its properties.
 func OverrideAndroidAppModuleFactory() android.Module {
 	m := &OverrideAndroidApp{}
-	m.AddProperties(&overridableAppProperties{})
+	m.AddProperties(
+		&OverridableDeviceProperties{},
+		&overridableAppProperties{},
+	)
 
 	android.InitAndroidMultiTargetsArchModule(m, android.DeviceSupported, android.MultilibCommon)
 	android.InitOverrideModule(m)

java/app_test.go

@@ -1981,6 +1981,80 @@ func TestOverrideAndroidApp(t *testing.T) {
 	}
 }
 
+func TestOverrideAndroidAppStem(t *testing.T) {
+	ctx, _ := testJava(t, `
+		android_app {
+			name: "foo",
+			srcs: ["a.java"],
+			sdk_version: "current",
+		}
+		override_android_app {
+			name: "bar",
+			base: "foo",
+		}
+		override_android_app {
+			name: "baz",
+			base: "foo",
+			stem: "baz_stem",
+		}
+		android_app {
+			name: "foo2",
+			srcs: ["a.java"],
+			sdk_version: "current",
+			stem: "foo2_stem",
+		}
+		override_android_app {
+			name: "bar2",
+			base: "foo2",
+		}
+		override_android_app {
+			name: "baz2",
+			base: "foo2",
+			stem: "baz2_stem",
+		}
+	`)
+	for _, expected := range []struct {
+		moduleName  string
+		variantName string
+		apkPath     string
+	}{
+		{
+			moduleName:  "foo",
+			variantName: "android_common",
+			apkPath:     "out/soong/target/product/test_device/system/app/foo/foo.apk",
+		},
+		{
+			moduleName:  "foo",
+			variantName: "android_common_bar",
+			apkPath:     "out/soong/target/product/test_device/system/app/bar/bar.apk",
+		},
+		{
+			moduleName:  "foo",
+			variantName: "android_common_baz",
+			apkPath:     "out/soong/target/product/test_device/system/app/baz_stem/baz_stem.apk",
+		},
+		{
+			moduleName:  "foo2",
+			variantName: "android_common",
+			apkPath:     "out/soong/target/product/test_device/system/app/foo2_stem/foo2_stem.apk",
+		},
+		{
+			moduleName:  "foo2",
+			variantName: "android_common_bar2",
+			// Note that this may cause the duplicate output error.
+			apkPath: "out/soong/target/product/test_device/system/app/foo2_stem/foo2_stem.apk",
+		},
+		{
+			moduleName:  "foo2",
+			variantName: "android_common_baz2",
+			apkPath:     "out/soong/target/product/test_device/system/app/baz2_stem/baz2_stem.apk",
+		},
+	} {
+		variant := ctx.ModuleForTests(expected.moduleName, expected.variantName)
+		variant.Output(expected.apkPath)
+	}
+}
+
 func TestOverrideAndroidAppDependency(t *testing.T) {
 	ctx, _ := testJava(t, `
 		android_app {

java/base.go

@@ -253,9 +253,6 @@ type DeviceProperties struct {
 	// otherwise provides defaults libraries to add to the bootclasspath.
 	System_modules *string
 
-	// set the name of the output
-	Stem *string
-
 	IsSDKLibrary bool `blueprint:"mutated"`
 
 	// If true, generate the signature file of APK Signing Scheme V4, along side the signed APK file.
@@ -267,6 +264,15 @@ type DeviceProperties struct {
 	SyspropPublicStub string `blueprint:"mutated"`
 }
 
+// Device properties that can be overridden by overriding module (e.g. override_android_app)
+type OverridableDeviceProperties struct {
+	// set the name of the output. If not set, `name` is used.
+	// To override a module with this property set, overriding module might need to set this as well.
+	// Otherwise, both the overridden and the overriding modules will have the same output name, which
+	// can cause the duplicate output error.
+	Stem *string
+}
+
 // Functionality common to Module and Import
 //
 // It is embedded in Module so its functionality can be used by methods in Module
@@ -389,6 +395,8 @@ type Module struct {
 	protoProperties  android.ProtoProperties
 	deviceProperties DeviceProperties
 
+	overridableDeviceProperties OverridableDeviceProperties
+
 	// jar file containing header classes including static library dependencies, suitable for
 	// inserting into the bootclasspath/classpath of another compile
 	headerJarFile android.Path
@@ -544,6 +552,7 @@ func (j *Module) addHostAndDeviceProperties() {
 	j.addHostProperties()
 	j.AddProperties(
 		&j.deviceProperties,
+		&j.overridableDeviceProperties,
 		&j.dexer.dexProperties,
 		&j.dexpreoptProperties,
 		&j.linter.properties,
@@ -1671,7 +1680,7 @@ func (j *Module) ShouldSupportSdkVersion(ctx android.BaseModuleContext, sdkVersi
 }
 
 func (j *Module) Stem() string {
-	return proptools.StringDefault(j.deviceProperties.Stem, j.Name())
+	return proptools.StringDefault(j.overridableDeviceProperties.Stem, j.Name())
 }
 
 func (j *Module) JacocoReportClassesFile() android.Path {

java/java.go

@@ -1867,6 +1867,7 @@ func DefaultsFactory() android.Module {
 	module.AddProperties(
 		&CommonProperties{},
 		&DeviceProperties{},
+		&OverridableDeviceProperties{},
 		&DexProperties{},
 		&DexpreoptProperties{},
 		&android.ProtoProperties{},