Add exported_plugins to java.Library.

The behaviour is similar to go/be#java_library.exported_plugins. Plugins added to exported_plugins of library X are not applied to the library itself, but rather to libraries that directly depend on the library X.

Test: m checkbuild
Bug: 139740873
Change-Id: I4042bd482ad9cb12d6fbaac51f039d38b1b7a428

java/aar.go

@@ -694,6 +694,10 @@ func (a *AARImport) ExportedSdkLibs() []string {
 	return nil
 }
 
+func (d *AARImport) ExportedPlugins() (android.Paths, []string) {
+	return nil, nil
+}
+
 func (a *AARImport) SrcJarArgs() ([]string, android.Paths) {
 	return nil, nil
 }

java/device_host_converter.go

@@ -162,6 +162,10 @@ func (d *DeviceHostConverter) ExportedSdkLibs() []string {
 	return nil
 }
 
+func (d *DeviceHostConverter) ExportedPlugins() (android.Paths, []string) {
+	return nil, nil
+}
+
 func (d *DeviceHostConverter) SrcJarArgs() ([]string, android.Paths) {
 	return d.srcJarArgs, d.srcJarDeps
 }

java/java.go

@@ -145,6 +145,9 @@ type CompilerProperties struct {
 	// List of modules to use as annotation processors
 	Plugins []string
 
+	// List of modules to export to libraries that directly depend on this library as annotation processors
+	Exported_plugins []string
+
 	// The number of Java source entries each Javac instance can process
 	Javac_shard_size *int64
 
@@ -360,10 +363,16 @@ type Module struct {
 	// manifest file to use instead of properties.Manifest
 	overrideManifest android.OptionalPath
 
-	// list of SDK lib names that this java moudule is exporting
+	// list of SDK lib names that this java module is exporting
 	exportedSdkLibs []string
 
-	// list of source files, collected from srcFiles with uniqie java and all kt files,
+	// list of plugins that this java module is exporting
+	exportedPluginJars android.Paths
+
+	// list of plugins that this java module is exporting
+	exportedPluginClasses []string
+
+	// list of source files, collected from srcFiles with unique java and all kt files,
 	// will be used by android.IDEInfo struct
 	expandIDEInfoCompiledSrcs []string
 
@@ -410,6 +419,7 @@ type Dependency interface {
 	DexJar() android.Path
 	AidlIncludeDirs() android.Paths
 	ExportedSdkLibs() []string
+	ExportedPlugins() (android.Paths, []string)
 	SrcJarArgs() ([]string, android.Paths)
 	BaseModuleName() string
 }
@@ -452,6 +462,7 @@ var (
 	libTag                = dependencyTag{name: "javalib"}
 	java9LibTag           = dependencyTag{name: "java9lib"}
 	pluginTag             = dependencyTag{name: "plugin"}
+	exportedPluginTag     = dependencyTag{name: "exported-plugin"}
 	bootClasspathTag      = dependencyTag{name: "bootclasspath"}
 	systemModulesTag      = dependencyTag{name: "system modules"}
 	frameworkResTag       = dependencyTag{name: "framework-res"}
@@ -561,6 +572,7 @@ func (j *Module) deps(ctx android.BottomUpMutatorContext) {
 	ctx.AddVariationDependencies(nil, staticLibTag, j.properties.Static_libs...)
 
 	ctx.AddFarVariationDependencies(ctx.Config().BuildOSCommonTarget.Variations(), pluginTag, j.properties.Plugins...)
+	ctx.AddFarVariationDependencies(ctx.Config().BuildOSCommonTarget.Variations(), exportedPluginTag, j.properties.Exported_plugins...)
 
 	android.ProtoDeps(ctx, &j.protoProperties)
 	if j.hasSrcExt(".proto") {
@@ -800,6 +812,8 @@ func (j *Module) collectDeps(ctx android.ModuleContext) deps {
 				// sdk lib names from dependencies are re-exported
 				j.exportedSdkLibs = append(j.exportedSdkLibs, dep.ExportedSdkLibs()...)
 				deps.aidlIncludeDirs = append(deps.aidlIncludeDirs, dep.AidlIncludeDirs()...)
+				pluginJars, pluginClasses := dep.ExportedPlugins()
+				addPlugins(&deps, pluginJars, pluginClasses...)
 			case java9LibTag:
 				deps.java9Classpath = append(deps.java9Classpath, dep.HeaderJars()...)
 			case staticLibTag:
@@ -810,16 +824,31 @@ func (j *Module) collectDeps(ctx android.ModuleContext) deps {
 				// sdk lib names from dependencies are re-exported
 				j.exportedSdkLibs = append(j.exportedSdkLibs, dep.ExportedSdkLibs()...)
 				deps.aidlIncludeDirs = append(deps.aidlIncludeDirs, dep.AidlIncludeDirs()...)
+				pluginJars, pluginClasses := dep.ExportedPlugins()
+				addPlugins(&deps, pluginJars, pluginClasses...)
 			case pluginTag:
 				if plugin, ok := dep.(*Plugin); ok {
-					deps.processorPath = append(deps.processorPath, dep.ImplementationAndResourcesJars()...)
 					if plugin.pluginProperties.Processor_class != nil {
-						deps.processorClasses = append(deps.processorClasses, *plugin.pluginProperties.Processor_class)
+						addPlugins(&deps, plugin.ImplementationAndResourcesJars(), *plugin.pluginProperties.Processor_class)
+					} else {
+						addPlugins(&deps, plugin.ImplementationAndResourcesJars())
 					}
 					deps.disableTurbine = deps.disableTurbine || Bool(plugin.pluginProperties.Generates_api)
 				} else {
 					ctx.PropertyErrorf("plugins", "%q is not a java_plugin module", otherName)
 				}
+			case exportedPluginTag:
+				if plugin, ok := dep.(*Plugin); ok {
+					if plugin.pluginProperties.Generates_api != nil && *plugin.pluginProperties.Generates_api {
+						ctx.PropertyErrorf("exported_plugins", "Cannot export plugins with generates_api = true, found %v", otherName)
+					}
+					j.exportedPluginJars = append(j.exportedPluginJars, plugin.ImplementationAndResourcesJars()...)
+					if plugin.pluginProperties.Processor_class != nil {
+						j.exportedPluginClasses = append(j.exportedPluginClasses, *plugin.pluginProperties.Processor_class)
+					}
+				} else {
+					ctx.PropertyErrorf("exported_plugins", "%q is not a java_plugin module", otherName)
+				}
 			case frameworkApkTag:
 				if ctx.ModuleName() == "android_stubs_current" ||
 					ctx.ModuleName() == "android_system_stubs_current" ||
@@ -875,6 +904,11 @@ func (j *Module) collectDeps(ctx android.ModuleContext) deps {
 	return deps
 }
 
+func addPlugins(deps *deps, pluginJars android.Paths, pluginClasses ...string) {
+	deps.processorPath = append(deps.processorPath, pluginJars...)
+	deps.processorClasses = append(deps.processorClasses, pluginClasses...)
+}
+
 func getJavaVersion(ctx android.ModuleContext, javaVersion string, sdkContext sdkContext) javaVersion {
 	v := sdkContext.sdkVersion()
 	// For PDK builds, use the latest SDK version instead of "current"
@@ -1569,6 +1603,10 @@ func (j *Module) ExportedSdkLibs() []string {
 	return j.exportedSdkLibs
 }
 
+func (j *Module) ExportedPlugins() (android.Paths, []string) {
+	return j.exportedPluginJars, j.exportedPluginClasses
+}
+
 func (j *Module) SrcJarArgs() ([]string, android.Paths) {
 	return j.srcJarArgs, j.srcJarDeps
 }
@@ -2143,6 +2181,10 @@ func (j *Import) ExportedSdkLibs() []string {
 	return j.exportedSdkLibs
 }
 
+func (j *Import) ExportedPlugins() (android.Paths, []string) {
+	return nil, nil
+}
+
 func (j *Import) SrcJarArgs() ([]string, android.Paths) {
 	return nil, nil
 }

java/java_test.go

@@ -332,6 +332,89 @@ func TestSimple(t *testing.T) {
 	}
 }
 
+func TestExportedPlugins(t *testing.T) {
+	type Result struct {
+		library    string
+		processors string
+	}
+	var tests = []struct {
+		name    string
+		extra   string
+		results []Result
+	}{
+		{
+			name:    "Exported plugin is not a direct plugin",
+			extra:   `java_library { name: "exports", srcs: ["a.java"], exported_plugins: ["plugin"] }`,
+			results: []Result{{library: "exports", processors: "-proc:none"}},
+		},
+		{
+			name: "Exports plugin to dependee",
+			extra: `
+				java_library{name: "exports", exported_plugins: ["plugin"]}
+				java_library{name: "foo", srcs: ["a.java"], libs: ["exports"]}
+				java_library{name: "bar", srcs: ["a.java"], static_libs: ["exports"]}
+			`,
+			results: []Result{
+				{library: "foo", processors: "-processor com.android.TestPlugin"},
+				{library: "bar", processors: "-processor com.android.TestPlugin"},
+			},
+		},
+		{
+			name: "Exports plugin to android_library",
+			extra: `
+				java_library{name: "exports", exported_plugins: ["plugin"]}
+				android_library{name: "foo", srcs: ["a.java"],  libs: ["exports"]}
+				android_library{name: "bar", srcs: ["a.java"], static_libs: ["exports"]}
+			`,
+			results: []Result{
+				{library: "foo", processors: "-processor com.android.TestPlugin"},
+				{library: "bar", processors: "-processor com.android.TestPlugin"},
+			},
+		},
+		{
+			name: "Exports plugin is not propagated via transitive deps",
+			extra: `
+				java_library{name: "exports", exported_plugins: ["plugin"]}
+				java_library{name: "foo", srcs: ["a.java"], libs: ["exports"]}
+				java_library{name: "bar", srcs: ["a.java"], static_libs: ["foo"]}
+			`,
+			results: []Result{
+				{library: "foo", processors: "-processor com.android.TestPlugin"},
+				{library: "bar", processors: "-proc:none"},
+			},
+		},
+		{
+			name: "Exports plugin appends to plugins",
+			extra: `
+                java_plugin{name: "plugin2", processor_class: "com.android.TestPlugin2"}
+				java_library{name: "exports", exported_plugins: ["plugin"]}
+				java_library{name: "foo", srcs: ["a.java"], libs: ["exports"], plugins: ["plugin2"]}
+			`,
+			results: []Result{
+				{library: "foo", processors: "-processor com.android.TestPlugin,com.android.TestPlugin2"},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			ctx, _ := testJava(t, `
+				java_plugin {
+					name: "plugin",
+					processor_class: "com.android.TestPlugin",
+				}
+			`+test.extra)
+
+			for _, want := range test.results {
+				javac := ctx.ModuleForTests(want.library, "android_common").Rule("javac")
+				if javac.Args["processor"] != want.processors {
+					t.Errorf("For library %v, expected %v, found %v", want.library, want.processors, javac.Args["processor"])
+				}
+			}
+		})
+	}
+}
+
 func TestSdkVersionByPartition(t *testing.T) {
 	testJavaError(t, "sdk_version must have a value when the module is located at vendor or product", `
 		java_library {