Revert "Export implementation class jars for java_boot_libs"

This reverts commit 22ff0aaf51.

The workaround to support hidden API generation with prebuilts by
passing the full implementation jars through to the SDK snapshot is no
longer needed as the monolithic hidden API flag generation uses the
prebuilt flag files that are already part of the snapshot.

This change reverts that previous workaround.

Bug: 192868581
Test: - Update the prebuilts
      DIST_DIR=$PWD/dist TARGET_BUILD_VARIANT=userdebug art/build/build-art-module.sh --skip-apex
      packages/modules/ArtPrebuilt/update-art-module-prebuilts.py --local-dist=dist --skip-cls --skip-apex
      - Build hidden API flags to make sure it does not fail
Change-Id: Idb3fde6f7dcb171677316d8794a4af91ede1f7e0

android/sdk.go

@@ -239,6 +239,12 @@ type SnapshotBuilder interface {
 	// to the zip
 	CopyToSnapshot(src Path, dest string)
 
+	// Return the path to an empty file.
+	//
+	// This can be used by sdk member types that need to create an empty file in the snapshot, simply
+	// pass the value returned from this to the CopyToSnapshot() method.
+	EmptyFile() Path
+
 	// Unzip the supplied zip into the snapshot relative directory destDir.
 	UnzipToSnapshot(zipPath Path, destDir string)
 

java/java.go

@@ -130,11 +130,19 @@ var (
 			PropertyName: "java_boot_libs",
 			SupportsSdk:  true,
 		},
-		// Temporarily export implementation classes jar for java_boot_libs as it is required for the
-		// hiddenapi processing.
-		// TODO(b/179354495): Revert once hiddenapi processing has been modularized.
-		exportImplementationClassesJar,
-		sdkSnapshotFilePathForJar,
+		func(ctx android.SdkMemberContext, j *Library) android.Path {
+			// Java boot libs are only provided in the SDK to provide access to their dex implementation
+			// jar for use by dexpreopting and boot jars package check. They do not need to provide an
+			// actual implementation jar but the java_import will need a file that exists so just copy an
+			// empty file. Any attempt to use that file as a jar will cause a build error.
+			return ctx.SnapshotBuilder().EmptyFile()
+		},
+		func(osPrefix, name string) string {
+			// Create a special name for the implementation jar to try and provide some useful information
+			// to a developer that attempts to compile against this.
+			// TODO(b/175714559): Provide a proper error message in Soong not ninja.
+			return filepath.Join(osPrefix, "java_boot_libs", "snapshot", "jars", "are", "invalid", name+jarFileSuffix)
+		},
 		onlyCopyJarToSnapshot,
 	}
 

sdk/bootclasspath_fragment_sdk_test.go

@@ -147,7 +147,7 @@ java_import {
     prefer: false,
     visibility: ["//visibility:public"],
     apex_available: ["com.android.art"],
-    jars: ["java/mybootlib.jar"],
+    jars: ["java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar"],
 }
 `),
 		checkVersionedAndroidBpContents(`
@@ -174,7 +174,7 @@ java_import {
     sdk_member_name: "mybootlib",
     visibility: ["//visibility:public"],
     apex_available: ["com.android.art"],
-    jars: ["java/mybootlib.jar"],
+    jars: ["java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar"],
 }
 
 sdk_snapshot {
@@ -190,7 +190,7 @@ sdk_snapshot {
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/metadata.csv -> hiddenapi/metadata.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/index.csv -> hiddenapi/index.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/all-flags.csv -> hiddenapi/all-flags.csv
-.intermediates/mybootlib/android_common/javac/mybootlib.jar -> java/mybootlib.jar
+.intermediates/mysdk/common_os/empty -> java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar
 		`),
 		snapshotTestPreparer(checkSnapshotWithoutSource, preparerForSnapshot),
 
@@ -345,7 +345,7 @@ java_import {
     prefer: false,
     visibility: ["//visibility:public"],
     apex_available: ["myapex"],
-    jars: ["java/mybootlib.jar"],
+    jars: ["java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar"],
     permitted_packages: ["mybootlib"],
 }
 
@@ -429,7 +429,7 @@ java_import {
     sdk_member_name: "mybootlib",
     visibility: ["//visibility:public"],
     apex_available: ["myapex"],
-    jars: ["java/mybootlib.jar"],
+    jars: ["java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar"],
     permitted_packages: ["mybootlib"],
 }
 
@@ -499,7 +499,7 @@ sdk_snapshot {
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/metadata.csv -> hiddenapi/metadata.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/index.csv -> hiddenapi/index.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/all-flags.csv -> hiddenapi/all-flags.csv
-.intermediates/mybootlib/android_common/javac/mybootlib.jar -> java/mybootlib.jar
+.intermediates/mysdk/common_os/empty -> java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar
 .intermediates/myothersdklibrary.stubs/android_common/javac/myothersdklibrary.stubs.jar -> sdk_library/public/myothersdklibrary-stubs.jar
 .intermediates/myothersdklibrary.stubs.source/android_common/metalava/myothersdklibrary.stubs.source_api.txt -> sdk_library/public/myothersdklibrary.txt
 .intermediates/myothersdklibrary.stubs.source/android_common/metalava/myothersdklibrary.stubs.source_removed.txt -> sdk_library/public/myothersdklibrary-removed.txt
@@ -851,7 +851,7 @@ java_import {
     prefer: false,
     visibility: ["//visibility:public"],
     apex_available: ["myapex"],
-    jars: ["java/mybootlib.jar"],
+    jars: ["java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar"],
     permitted_packages: ["mybootlib"],
 }
 
@@ -886,7 +886,7 @@ my-unsupported-packages.txt -> hiddenapi/my-unsupported-packages.txt
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/metadata.csv -> hiddenapi/metadata.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/index.csv -> hiddenapi/index.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/all-flags.csv -> hiddenapi/all-flags.csv
-.intermediates/mybootlib/android_common/javac/mybootlib.jar -> java/mybootlib.jar
+.intermediates/mysdk/common_os/empty -> java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar
 .intermediates/mysdklibrary.stubs/android_common/javac/mysdklibrary.stubs.jar -> sdk_library/public/mysdklibrary-stubs.jar
 .intermediates/mysdklibrary.stubs.source/android_common/metalava/mysdklibrary.stubs.source_api.txt -> sdk_library/public/mysdklibrary.txt
 .intermediates/mysdklibrary.stubs.source/android_common/metalava/mysdklibrary.stubs.source_removed.txt -> sdk_library/public/mysdklibrary-removed.txt

sdk/java_sdk_test.go

@@ -453,7 +453,7 @@ java_import {
     prefer: false,
     visibility: ["//visibility:public"],
     apex_available: ["//apex_available:platform"],
-    jars: ["java/myjavalib.jar"],
+    jars: ["java_boot_libs/snapshot/jars/are/invalid/myjavalib.jar"],
     permitted_packages: ["pkg.myjavalib"],
 }
 `),
@@ -465,7 +465,7 @@ java_import {
     sdk_member_name: "myjavalib",
     visibility: ["//visibility:public"],
     apex_available: ["//apex_available:platform"],
-    jars: ["java/myjavalib.jar"],
+    jars: ["java_boot_libs/snapshot/jars/are/invalid/myjavalib.jar"],
     permitted_packages: ["pkg.myjavalib"],
 }
 
@@ -474,9 +474,10 @@ module_exports_snapshot {
     visibility: ["//visibility:public"],
     java_boot_libs: ["myexports_myjavalib@current"],
 }
+
 `),
 		checkAllCopyRules(`
-.intermediates/myjavalib/android_common/withres/myjavalib.jar -> java/myjavalib.jar
+.intermediates/myexports/common_os/empty -> java_boot_libs/snapshot/jars/are/invalid/myjavalib.jar
 `),
 	)
 }

sdk/update.go

@@ -1029,6 +1029,9 @@ type snapshotBuilder struct {
 	filesToZip  android.Paths
 	zipsToMerge android.Paths
 
+	// The path to an empty file.
+	emptyFile android.WritablePath
+
 	prebuiltModules map[string]*bpModule
 	prebuiltOrder   []*bpModule
 
@@ -1079,6 +1082,19 @@ func (s *snapshotBuilder) UnzipToSnapshot(zipPath android.Path, destDir string)
 	s.zipsToMerge = append(s.zipsToMerge, tmpZipPath)
 }
 
+func (s *snapshotBuilder) EmptyFile() android.Path {
+	if s.emptyFile == nil {
+		ctx := s.ctx
+		s.emptyFile = android.PathForModuleOut(ctx, "empty")
+		s.ctx.Build(pctx, android.BuildParams{
+			Rule:   android.Touch,
+			Output: s.emptyFile,
+		})
+	}
+
+	return s.emptyFile
+}
+
 func (s *snapshotBuilder) AddPrebuiltModule(member android.SdkMember, moduleType string) android.BpModule {
 	name := member.Name()
 	if s.prebuiltModules[name] != nil {