Add aconfig flag support for android_app

This change adds an overrideable property flags_packages to android_app,
which is used to list the aconfig_declarations module names that the app
depends on. The build action of android_app is modified to pass all
flags text file provided by the aconfig_declarations to aapt2 link as
--feature-flags arguments.

Test: m nothing --no-skip-soong-tests
Bug: 306024510
Change-Id: I4924f88b9954950cc1936a472cd7ac70f41add5d
diff --git a/java/aapt2.go b/java/aapt2.go
index 17ee6ee..445e912 100644
--- a/java/aapt2.go
+++ b/java/aapt2.go
@@ -202,7 +202,8 @@
 func aapt2Link(ctx android.ModuleContext,
 	packageRes, genJar, proguardOptions, rTxt android.WritablePath,
 	flags []string, deps android.Paths,
-	compiledRes, compiledOverlay, assetPackages android.Paths, splitPackages android.WritablePaths) {
+	compiledRes, compiledOverlay, assetPackages android.Paths, splitPackages android.WritablePaths,
+	featureFlagsPaths android.Paths) {
 
 	var inFlags []string
 
@@ -255,6 +256,11 @@
 		})
 	}
 
+	for _, featureFlagsPath := range featureFlagsPaths {
+		deps = append(deps, featureFlagsPath)
+		inFlags = append(inFlags, "--feature-flags", "@"+featureFlagsPath.String())
+	}
+
 	// Note the absence of splitPackages. The caller is supposed to compose and provide --split flag
 	// values via the flags parameter when it wants to split outputs.
 	// TODO(b/174509108): Perhaps we can process it in this func while keeping the code reasonably
diff --git a/java/aar.go b/java/aar.go
index 57a05d4..1ab4529 100644
--- a/java/aar.go
+++ b/java/aar.go
@@ -349,6 +349,7 @@
 	excludedLibs                   []string
 	enforceDefaultTargetSdkVersion bool
 	extraLinkFlags                 []string
+	aconfigTextFiles               android.Paths
 }
 
 func (a *aapt) buildActions(ctx android.ModuleContext, opts aaptBuildActionOptions) {
@@ -529,7 +530,8 @@
 		transitiveAssets = android.ReverseSliceInPlace(staticDeps.assets())
 	}
 	aapt2Link(ctx, packageRes, srcJar, proguardOptionsFile, rTxt,
-		linkFlags, linkDeps, compiledRes, compiledOverlay, transitiveAssets, splitPackages)
+		linkFlags, linkDeps, compiledRes, compiledOverlay, transitiveAssets, splitPackages,
+		opts.aconfigTextFiles)
 	// Extract assets from the resource package output so that they can be used later in aapt2link
 	// for modules that depend on this one.
 	if android.PrefixInList(linkFlags, "-A ") {
@@ -1193,7 +1195,7 @@
 
 	transitiveAssets := android.ReverseSliceInPlace(staticDeps.assets())
 	aapt2Link(ctx, a.exportPackage, nil, proguardOptionsFile, a.rTxt,
-		linkFlags, linkDeps, nil, overlayRes, transitiveAssets, nil)
+		linkFlags, linkDeps, nil, overlayRes, transitiveAssets, nil, nil)
 
 	a.rJar = android.PathForModuleOut(ctx, "busybox/R.jar")
 	resourceProcessorBusyBoxGenerateBinaryR(ctx, a.rTxt, a.manifest, a.rJar, nil, true)
diff --git a/java/app.go b/java/app.go
index 0f46b4e..d8822af 100755
--- a/java/app.go
+++ b/java/app.go
@@ -22,7 +22,9 @@
 	"path/filepath"
 	"strings"
 
+	"android/soong/aconfig"
 	"android/soong/testing"
+
 	"github.com/google/blueprint"
 	"github.com/google/blueprint/proptools"
 
@@ -170,6 +172,9 @@
 	// binaries would be installed by default (in PRODUCT_PACKAGES) the other binary will be removed
 	// from PRODUCT_PACKAGES.
 	Overrides []string
+
+	// Names of aconfig_declarations modules that specify aconfig flags that the app depends on.
+	Flags_packages []string
 }
 
 type AndroidApp struct {
@@ -316,6 +321,10 @@
 				`must be names of android_app_certificate modules in the form ":module"`)
 		}
 	}
+
+	for _, aconfig_declaration := range a.overridableAppProperties.Flags_packages {
+		ctx.AddDependency(ctx.Module(), aconfigDeclarationTag, aconfig_declaration)
+	}
 }
 
 func (a *AndroidTestHelperApp) GenerateAndroidBuildActions(ctx android.ModuleContext) {
@@ -500,13 +509,27 @@
 	if a.Updatable() {
 		a.aapt.defaultManifestVersion = android.DefaultUpdatableModuleVersion
 	}
+
+	var aconfigTextFilePaths android.Paths
+	ctx.VisitDirectDepsWithTag(aconfigDeclarationTag, func(dep android.Module) {
+		if provider, ok := ctx.OtherModuleProvider(dep, aconfig.DeclarationsProviderKey).(aconfig.DeclarationsProviderData); ok {
+			aconfigTextFilePaths = append(aconfigTextFilePaths, provider.IntermediateDumpOutputPath)
+		} else {
+			ctx.ModuleErrorf("Only aconfig_declarations module type is allowed for "+
+				"flags_packages property, but %s is not aconfig_declarations module type",
+				dep.Name(),
+			)
+		}
+	})
+
 	a.aapt.buildActions(ctx,
 		aaptBuildActionOptions{
-			android.SdkContext(a),
-			a.classLoaderContexts,
-			a.usesLibraryProperties.Exclude_uses_libs,
-			a.enforceDefaultTargetSdkVersion(),
-			aaptLinkFlags,
+			sdkContext:                     android.SdkContext(a),
+			classLoaderContexts:            a.classLoaderContexts,
+			excludedLibs:                   a.usesLibraryProperties.Exclude_uses_libs,
+			enforceDefaultTargetSdkVersion: a.enforceDefaultTargetSdkVersion(),
+			extraLinkFlags:                 aaptLinkFlags,
+			aconfigTextFiles:               aconfigTextFilePaths,
 		},
 	)
 
diff --git a/java/app_test.go b/java/app_test.go
index 5cb4a23..0936b28 100644
--- a/java/app_test.go
+++ b/java/app_test.go
@@ -4333,3 +4333,48 @@
 	)
 
 }
+
+func TestAppFlagsPackages(t *testing.T) {
+	ctx := testApp(t, `
+		android_app {
+			name: "foo",
+			srcs: ["a.java"],
+			sdk_version: "current",
+			flags_packages: [
+				"bar",
+				"baz",
+			],
+		}
+		aconfig_declarations {
+			name: "bar",
+			package: "com.example.package",
+			srcs: [
+				"bar.aconfig",
+			],
+		}
+		aconfig_declarations {
+			name: "baz",
+			package: "com.example.package",
+			srcs: [
+				"baz.aconfig",
+			],
+		}
+	`)
+
+	foo := ctx.ModuleForTests("foo", "android_common")
+
+	// android_app module depends on aconfig_declarations listed in flags_packages
+	android.AssertBoolEquals(t, "foo expected to depend on bar", true,
+		CheckModuleHasDependency(t, ctx, "foo", "android_common", "bar"))
+
+	android.AssertBoolEquals(t, "foo expected to depend on baz", true,
+		CheckModuleHasDependency(t, ctx, "foo", "android_common", "baz"))
+
+	aapt2LinkRule := foo.Rule("android/soong/java.aapt2Link")
+	linkInFlags := aapt2LinkRule.Args["inFlags"]
+	android.AssertStringDoesContain(t,
+		"aapt2 link command expected to pass feature flags arguments",
+		linkInFlags,
+		"--feature-flags @out/soong/.intermediates/bar/intermediate.txt --feature-flags @out/soong/.intermediates/baz/intermediate.txt",
+	)
+}
diff --git a/java/java.go b/java/java.go
index 2236d05..d5d22b2 100644
--- a/java/java.go
+++ b/java/java.go
@@ -409,6 +409,7 @@
 	syspropPublicStubDepTag = dependencyTag{name: "sysprop public stub"}
 	javaApiContributionTag  = dependencyTag{name: "java-api-contribution"}
 	depApiSrcsTag           = dependencyTag{name: "dep-api-srcs"}
+	aconfigDeclarationTag   = dependencyTag{name: "aconfig-declaration"}
 	jniInstallTag           = installDependencyTag{name: "jni install"}
 	binaryInstallTag        = installDependencyTag{name: "binary install"}
 	usesLibReqTag           = makeUsesLibraryDependencyTag(dexpreopt.AnySdkVersion, false)
diff --git a/java/java_test.go b/java/java_test.go
index 0c750eb..d4b056b 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -26,6 +26,7 @@
 
 	"github.com/google/blueprint/proptools"
 
+	"android/soong/aconfig"
 	"android/soong/android"
 	"android/soong/cc"
 	"android/soong/dexpreopt"
@@ -47,6 +48,8 @@
 	cc.PrepareForTestWithCcBuildComponents,
 	// Include all the default java modules.
 	PrepareForTestWithDexpreopt,
+	// Include aconfig modules.
+	aconfig.PrepareForTestWithAconfigBuildComponents,
 )
 
 func TestMain(m *testing.M) {