Merge changes from topic "stub_validation" into main

* changes:
  Add current api check as validation for from-text stub generation
  Disable full_api_surface_stubs for some java_api_library modules
diff --git a/java/core-libraries/Android.bp b/java/core-libraries/Android.bp
index 4380f4f..8b7387a 100644
--- a/java/core-libraries/Android.bp
+++ b/java/core-libraries/Android.bp
@@ -66,6 +66,7 @@
     libs: [
         "stub-annotations",
     ],
+    enable_validation: false,
 }
 
 java_library {
diff --git a/java/droidstubs.go b/java/droidstubs.go
index 5432ce7..8ab2f2a 100644
--- a/java/droidstubs.go
+++ b/java/droidstubs.go
@@ -171,6 +171,10 @@
 	ApiStubsSrcProvider
 }
 
+type currentApiTimestampProvider interface {
+	CurrentApiTimestamp() android.Path
+}
+
 // droidstubs passes sources files through Metalava to generate stub .java files that only contain the API to be
 // documented, filtering out hidden classes and methods.  The resulting .java files are intended to be passed to
 // a droiddoc module to generate documentation.
@@ -238,10 +242,15 @@
 	return d.stubsSrcJar
 }
 
+func (d *Droidstubs) CurrentApiTimestamp() android.Path {
+	return d.checkCurrentApiTimestamp
+}
+
 var metalavaMergeAnnotationsDirTag = dependencyTag{name: "metalava-merge-annotations-dir"}
 var metalavaMergeInclusionAnnotationsDirTag = dependencyTag{name: "metalava-merge-inclusion-annotations-dir"}
 var metalavaAPILevelsAnnotationsDirTag = dependencyTag{name: "metalava-api-levels-annotations-dir"}
 var metalavaAPILevelsModuleTag = dependencyTag{name: "metalava-api-levels-module-tag"}
+var metalavaCurrentApiTimestampTag = dependencyTag{name: "metalava-current-api-timestamp-tag"}
 
 func (d *Droidstubs) DepsMutator(ctx android.BottomUpMutatorContext) {
 	d.Javadoc.addDeps(ctx)
diff --git a/java/droidstubs_test.go b/java/droidstubs_test.go
index e149b98..f86e1ac 100644
--- a/java/droidstubs_test.go
+++ b/java/droidstubs_test.go
@@ -392,7 +392,7 @@
 						removed_api_file: "A/removed.txt",
 					}
 				},
-				visibility: ["//a"],
+				visibility: ["//a", "//b"],
 			}
 		`,
 		map[string][]byte{
diff --git a/java/java.go b/java/java.go
index 3b20ea4..990a084 100644
--- a/java/java.go
+++ b/java/java.go
@@ -1664,6 +1664,8 @@
 	extractedSrcJar           android.WritablePath
 	// .dex of stubs, used for hiddenapi processing
 	dexJarFile OptionalDexJarPath
+
+	validationPaths android.Paths
 }
 
 type JavaApiLibraryProperties struct {
@@ -1699,6 +1701,12 @@
 	// The jar will also be passed to metalava as a classpath to
 	// generate compilable stubs.
 	System_modules *string
+
+	// If true, the module runs validation on the API signature files provided
+	// by the modules passed via api_contributions by checking if the files are
+	// in sync with the source Java files. However, the environment variable
+	// DISABLE_STUB_VALIDATION has precedence over this property.
+	Enable_validation *bool
 }
 
 func ApiLibraryFactory() android.Module {
@@ -1787,6 +1795,12 @@
 	}
 }
 
+func (al *ApiLibrary) addValidation(ctx android.ModuleContext, cmd *android.RuleBuilderCommand, validationPaths android.Paths) {
+	for _, validationPath := range validationPaths {
+		cmd.Validation(validationPath)
+	}
+}
+
 // This method extracts the stub class files from the stub jar file provided
 // from full_api_surface_stub module instead of compiling the srcjar generated from invoking metalava.
 // This method is used because metalava can generate compilable from-text stubs only when
@@ -1823,8 +1837,28 @@
 
 func (al *ApiLibrary) DepsMutator(ctx android.BottomUpMutatorContext) {
 	apiContributions := al.properties.Api_contributions
+	addValidations := !ctx.Config().IsEnvTrue("DISABLE_STUB_VALIDATION") &&
+		proptools.BoolDefault(al.properties.Enable_validation, true)
 	for _, apiContributionName := range apiContributions {
 		ctx.AddDependency(ctx.Module(), javaApiContributionTag, apiContributionName)
+
+		// Add the java_api_contribution module generating droidstubs module
+		// as dependency when validation adding conditions are met and
+		// the java_api_contribution module name has ".api.contribution" suffix.
+		// All droidstubs-generated modules possess the suffix in the name,
+		// but there is no such guarantee for tests.
+		if addValidations {
+			if strings.HasSuffix(apiContributionName, ".api.contribution") {
+				ctx.AddDependency(ctx.Module(), metalavaCurrentApiTimestampTag, strings.TrimSuffix(apiContributionName, ".api.contribution"))
+			} else {
+				ctx.ModuleErrorf("Validation is enabled for module %s but a "+
+					"current timestamp provider is not found for the api "+
+					"contribution %s",
+					ctx.ModuleName(),
+					apiContributionName,
+				)
+			}
+		}
 	}
 	ctx.AddVariationDependencies(nil, libTag, al.properties.Libs...)
 	ctx.AddVariationDependencies(nil, staticLibTag, al.properties.Static_libs...)
@@ -1862,8 +1896,7 @@
 		android.PathForModuleOut(ctx, "metalava.sbox.textproto")).
 		SandboxInputs()
 
-	var stubsDir android.OptionalPath
-	stubsDir = android.OptionalPathForPath(android.PathForModuleOut(ctx, "metalava", "stubsDir"))
+	stubsDir := android.OptionalPathForPath(android.PathForModuleOut(ctx, "metalava", "stubsDir"))
 	rule.Command().Text("rm -rf").Text(stubsDir.String())
 	rule.Command().Text("mkdir -p").Text(stubsDir.String())
 
@@ -1895,6 +1928,10 @@
 		case systemModulesTag:
 			module := dep.(SystemModulesProvider)
 			systemModulesPaths = append(systemModulesPaths, module.HeaderJars()...)
+		case metalavaCurrentApiTimestampTag:
+			if currentApiTimestampProvider, ok := dep.(currentApiTimestampProvider); ok {
+				al.validationPaths = append(al.validationPaths, currentApiTimestampProvider.CurrentApiTimestamp())
+			}
 		}
 	})
 
@@ -1918,6 +1955,8 @@
 		cmd.FlagWithInput("--migrate-nullness ", previousApi)
 	}
 
+	al.addValidation(ctx, cmd, al.validationPaths)
+
 	al.stubsSrcJar = android.PathForModuleOut(ctx, "metalava", ctx.ModuleName()+"-"+"stubs.srcjar")
 	al.stubsJarWithoutStaticLibs = android.PathForModuleOut(ctx, "metalava", "stubs.jar")
 	al.stubsJar = android.PathForModuleOut(ctx, ctx.ModuleName(), fmt.Sprintf("%s.jar", ctx.ModuleName()))
diff --git a/java/java_test.go b/java/java_test.go
index 6b8b735..c4fc55b 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -1847,9 +1847,17 @@
 }
 
 func TestJavaApiContributionEmptyApiFile(t *testing.T) {
-	testJavaError(t,
+	android.GroupFixturePreparers(
+		prepareForJavaTest,
+		android.FixtureMergeEnv(
+			map[string]string{
+				"DISABLE_STUB_VALIDATION": "true",
+			},
+		),
+	).ExtendWithErrorHandler(android.FixtureExpectsAtLeastOneErrorMatchingPattern(
 		"Error: foo has an empty api file.",
-		`java_api_contribution {
+	)).RunTestWithBp(t, `
+		java_api_contribution {
 			name: "foo",
 		}
 		java_api_library {
@@ -1874,7 +1882,20 @@
 		api_surface: "public",
 	}
 	`
-	ctx, _ := testJavaWithFS(t, `
+	ctx := android.GroupFixturePreparers(
+		prepareForJavaTest,
+		android.FixtureMergeMockFs(
+			map[string][]byte{
+				"a/Android.bp": []byte(provider_bp_a),
+				"b/Android.bp": []byte(provider_bp_b),
+			},
+		),
+		android.FixtureMergeEnv(
+			map[string]string{
+				"DISABLE_STUB_VALIDATION": "true",
+			},
+		),
+	).RunTestWithBp(t, `
 		java_api_library {
 			name: "bar1",
 			api_surface: "public",
@@ -1886,11 +1907,7 @@
 			api_surface: "system",
 			api_contributions: ["foo1", "foo2"],
 		}
-		`,
-		map[string][]byte{
-			"a/Android.bp": []byte(provider_bp_a),
-			"b/Android.bp": []byte(provider_bp_b),
-		})
+	`)
 
 	testcases := []struct {
 		moduleName         string
@@ -1944,7 +1961,22 @@
 		api_surface: "system",
 	}
 	`
-	ctx, _ := testJavaWithFS(t, `
+	ctx := android.GroupFixturePreparers(
+		prepareForJavaTest,
+		android.FixtureMergeMockFs(
+			map[string][]byte{
+				"a/Android.bp": []byte(provider_bp_a),
+				"b/Android.bp": []byte(provider_bp_b),
+				"c/Android.bp": []byte(provider_bp_c),
+				"d/Android.bp": []byte(provider_bp_d),
+			},
+		),
+		android.FixtureMergeEnv(
+			map[string]string{
+				"DISABLE_STUB_VALIDATION": "true",
+			},
+		),
+	).RunTestWithBp(t, `
 		java_defaults {
 			name: "baz1",
 			api_surface: "public",
@@ -1975,13 +2007,7 @@
 			defaults:["baz1", "baz2"],
 			api_contributions: ["foo4"],
 		}
-		`,
-		map[string][]byte{
-			"a/Android.bp": []byte(provider_bp_a),
-			"b/Android.bp": []byte(provider_bp_b),
-			"c/Android.bp": []byte(provider_bp_c),
-			"d/Android.bp": []byte(provider_bp_d),
-		})
+	`)
 
 	testcases := []struct {
 		moduleName         string
@@ -2026,7 +2052,20 @@
 		api_surface: "public",
 	}
 	`
-	ctx, _ := testJavaWithFS(t, `
+	ctx := android.GroupFixturePreparers(
+		prepareForJavaTest,
+		android.FixtureMergeMockFs(
+			map[string][]byte{
+				"a/Android.bp": []byte(provider_bp_a),
+				"b/Android.bp": []byte(provider_bp_b),
+			},
+		),
+		android.FixtureMergeEnv(
+			map[string]string{
+				"DISABLE_STUB_VALIDATION": "true",
+			},
+		),
+	).RunTestWithBp(t, `
 		java_api_library {
 			name: "bar1",
 			api_surface: "public",
@@ -2038,11 +2077,7 @@
 			api_surface: "system",
 			api_contributions: ["foo1", "foo2"],
 		}
-		`,
-		map[string][]byte{
-			"a/Android.bp": []byte(provider_bp_a),
-			"b/Android.bp": []byte(provider_bp_b),
-		})
+	`)
 
 	testcases := []struct {
 		moduleName    string
@@ -2094,7 +2129,24 @@
 	}
 	`
 
-	ctx, _ := testJavaWithFS(t, `
+	ctx := android.GroupFixturePreparers(
+		prepareForJavaTest,
+		android.FixtureMergeMockFs(
+			map[string][]byte{
+				"a/Android.bp": []byte(provider_bp_a),
+				"b/Android.bp": []byte(provider_bp_b),
+				"c/Android.bp": []byte(lib_bp_a),
+				"c/Lib.java":   {},
+				"d/Android.bp": []byte(lib_bp_b),
+				"d/Lib.java":   {},
+			},
+		),
+		android.FixtureMergeEnv(
+			map[string]string{
+				"DISABLE_STUB_VALIDATION": "true",
+			},
+		),
+	).RunTestWithBp(t, `
 		java_api_library {
 			name: "bar1",
 			api_surface: "public",
@@ -2108,15 +2160,7 @@
 			api_contributions: ["foo1", "foo2"],
 			libs: ["lib1", "lib2", "bar1"],
 		}
-		`,
-		map[string][]byte{
-			"a/Android.bp": []byte(provider_bp_a),
-			"b/Android.bp": []byte(provider_bp_b),
-			"c/Android.bp": []byte(lib_bp_a),
-			"c/Lib.java":   {},
-			"d/Android.bp": []byte(lib_bp_b),
-			"d/Lib.java":   {},
-		})
+	`)
 
 	testcases := []struct {
 		moduleName        string
@@ -2171,7 +2215,24 @@
 	}
 	`
 
-	ctx, _ := testJavaWithFS(t, `
+	ctx := android.GroupFixturePreparers(
+		prepareForJavaTest,
+		android.FixtureMergeMockFs(
+			map[string][]byte{
+				"a/Android.bp": []byte(provider_bp_a),
+				"b/Android.bp": []byte(provider_bp_b),
+				"c/Android.bp": []byte(lib_bp_a),
+				"c/Lib.java":   {},
+				"d/Android.bp": []byte(lib_bp_b),
+				"d/Lib.java":   {},
+			},
+		),
+		android.FixtureMergeEnv(
+			map[string]string{
+				"DISABLE_STUB_VALIDATION": "true",
+			},
+		),
+	).RunTestWithBp(t, `
 		java_api_library {
 			name: "bar1",
 			api_surface: "public",
@@ -2185,15 +2246,7 @@
 			api_contributions: ["foo1", "foo2"],
 			static_libs: ["lib1", "lib2", "bar1"],
 		}
-		`,
-		map[string][]byte{
-			"a/Android.bp": []byte(provider_bp_a),
-			"b/Android.bp": []byte(provider_bp_b),
-			"c/Android.bp": []byte(lib_bp_a),
-			"c/Lib.java":   {},
-			"d/Android.bp": []byte(lib_bp_b),
-			"d/Lib.java":   {},
-		})
+	`)
 
 	testcases := []struct {
 		moduleName        string
@@ -2242,19 +2295,28 @@
 	}
 	`
 
-	ctx, _ := testJavaWithFS(t, `
+	ctx := android.GroupFixturePreparers(
+		prepareForJavaTest,
+		android.FixtureMergeMockFs(
+			map[string][]byte{
+				"a/Android.bp": []byte(provider_bp_a),
+				"b/Android.bp": []byte(provider_bp_b),
+				"c/Android.bp": []byte(lib_bp_a),
+			},
+		),
+		android.FixtureMergeEnv(
+			map[string]string{
+				"DISABLE_STUB_VALIDATION": "true",
+			},
+		),
+	).RunTestWithBp(t, `
 		java_api_library {
 			name: "bar1",
 			api_surface: "public",
 			api_contributions: ["foo1"],
 			full_api_surface_stub: "lib1",
 		}
-		`,
-		map[string][]byte{
-			"a/Android.bp": []byte(provider_bp_a),
-			"b/Android.bp": []byte(provider_bp_b),
-			"c/Android.bp": []byte(lib_bp_a),
-		})
+	`)
 
 	m := ctx.ModuleForTests("bar1", "android_common")
 	manifest := m.Output("metalava.sbox.textproto")
@@ -2402,7 +2464,14 @@
 }
 
 func TestJavaApiContributionImport(t *testing.T) {
-	ctx, _ := testJava(t, `
+	ctx := android.GroupFixturePreparers(
+		prepareForJavaTest,
+		android.FixtureMergeEnv(
+			map[string]string{
+				"DISABLE_STUB_VALIDATION": "true",
+			},
+		),
+	).RunTestWithBp(t, `
 		java_api_library {
 			name: "foo",
 			api_contributions: ["bar"],
@@ -2483,3 +2552,50 @@
 	classPathFlag := "--classpath __SBOX_SANDBOX_DIR__/out/.intermediates/bar/android_common/turbine-combined/bar.jar"
 	android.AssertStringDoesContain(t, "command expected to contain classpath flag", manifestCommand, classPathFlag)
 }
+
+func TestApiLibraryDroidstubsDependency(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		prepareForJavaTest,
+		PrepareForTestWithJavaSdkLibraryFiles,
+		FixtureWithLastReleaseApis("foo"),
+		android.FixtureModifyConfig(func(config android.Config) {
+			config.SetApiLibraries([]string{"foo"})
+		}),
+		android.FixtureMergeMockFs(
+			map[string][]byte{
+				"A.java": nil,
+			},
+		),
+	).RunTestWithBp(t, `
+		java_api_library {
+			name: "foo",
+			api_contributions: [
+				"api-stubs-docs-non-updatable.api.contribution",
+			],
+			enable_validation: true,
+		}
+		java_api_library {
+			name: "bar",
+			api_contributions: [
+				"api-stubs-docs-non-updatable.api.contribution",
+			],
+			enable_validation: false,
+		}
+	`)
+
+	currentApiTimestampPath := "api-stubs-docs-non-updatable/android_common/metalava/check_current_api.timestamp"
+	foo := result.ModuleForTests("foo", "android_common").Module().(*ApiLibrary)
+	fooValidationPathsString := strings.Join(foo.validationPaths.Strings(), " ")
+	bar := result.ModuleForTests("bar", "android_common").Module().(*ApiLibrary)
+	barValidationPathsString := strings.Join(bar.validationPaths.Strings(), " ")
+	android.AssertStringDoesContain(t,
+		"Module expected to have validation",
+		fooValidationPathsString,
+		currentApiTimestampPath,
+	)
+	android.AssertStringDoesNotContain(t,
+		"Module expected to not have validation",
+		barValidationPathsString,
+		currentApiTimestampPath,
+	)
+}
diff --git a/java/sdk_library.go b/java/sdk_library.go
index f72c608..041aeb7 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -1838,6 +1838,7 @@
 		Static_libs           []string
 		Full_api_surface_stub *string
 		System_modules        *string
+		Enable_validation     *bool
 	}{}
 
 	props.Name = proptools.StringPtr(module.apiLibraryModuleName(apiScope))
@@ -1876,7 +1877,16 @@
 		props.Full_api_surface_stub = proptools.StringPtr(apiScope.kind.DefaultJavaLibraryName() + "_full.from-text")
 	}
 
+	// java_sdk_library modules that set sdk_version as none does not depend on other api
+	// domains. Therefore, java_api_library created from such modules should not depend on
+	// full_api_surface_stubs but create and compile stubs by the java_api_library module
+	// itself.
+	if module.SdkVersion(mctx).Kind == android.SdkNone {
+		props.Full_api_surface_stub = nil
+	}
+
 	props.System_modules = module.deviceProperties.System_modules
+	props.Enable_validation = proptools.BoolPtr(true)
 
 	mctx.CreateModule(ApiLibraryFactory, &props)
 }