Revert "Revert "Limit System SDK to 34 for Java modules in the v..."

Revert submission 2897568-revert-2894701-limit_systemsdk-WNEMOTGMRS

Reason for revert: Forward fix was merged

Reverted changes: /q/submissionid:2897568-revert-2894701-limit_systemsdk-WNEMOTGMRS

Change-Id: Id857406513fbf33a20e5d3836742ebd8a0105516
diff --git a/android/sdk_version.go b/android/sdk_version.go
index aafcee7..9c84a27 100644
--- a/android/sdk_version.go
+++ b/android/sdk_version.go
@@ -16,6 +16,7 @@
 
 import (
 	"fmt"
+	"reflect"
 	"strconv"
 	"strings"
 )
@@ -162,6 +163,17 @@
 	// If BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES has a numeric value,
 	// use it instead of "current" for the vendor partition.
 	currentSdkVersion := ctx.DeviceConfig().CurrentApiLevelForVendorModules()
+	// b/314011075: special case for Java modules in vendor partition. They can no longer use
+	// SDK 35 or later. Their maximum API level is limited to 34 (Android U). This is to
+	// discourage the use of Java APIs in the vendor partition which hasn't been officially
+	// supported since the Project Treble back in Android 10. We would like to eventually
+	// evacuate all Java modules from the partition, but that shall be done progressively.
+	// Note that the check for the availability of SDK 34 is to not break existing tests where
+	// any of the frozen SDK version is unavailable.
+	if isJava(ctx.Module()) && isSdkVersion34AvailableIn(ctx.Config()) {
+		currentSdkVersion = "34"
+	}
+
 	if currentSdkVersion == "current" {
 		return s
 	}
@@ -290,28 +302,79 @@
 	}
 }
 
+// Checks if the use of this SDK `s` is valid for the given module context `ctx`.
 func (s SdkSpec) ValidateSystemSdk(ctx EarlyModuleContext) bool {
-	// Ensures that the specified system SDK version is one of BOARD_SYSTEMSDK_VERSIONS (for vendor/product Java module)
-	// Assuming that BOARD_SYSTEMSDK_VERSIONS := 28 29,
-	// sdk_version of the modules in vendor/product that use system sdk must be either system_28, system_29 or system_current
-	if s.Kind != SdkSystem || s.ApiLevel.IsPreview() {
+	// Do some early checks. This check is currently only for Java modules. And our only concern
+	// is the use of "system" SDKs.
+	if !isJava(ctx.Module()) || s.Kind != SdkSystem {
 		return true
 	}
-	allowedVersions := ctx.DeviceConfig().PlatformSystemSdkVersions()
-	if ctx.DeviceSpecific() || ctx.SocSpecific() || (ctx.ProductSpecific() && ctx.Config().EnforceProductPartitionInterface()) {
-		systemSdkVersions := ctx.DeviceConfig().SystemSdkVersions()
-		if len(systemSdkVersions) > 0 {
-			allowedVersions = systemSdkVersions
+
+	inVendor := ctx.DeviceSpecific() || ctx.SocSpecific()
+	inProduct := ctx.ProductSpecific()
+	isProductUnbundled := ctx.Config().EnforceProductPartitionInterface()
+	inApex := false
+	if am, ok := ctx.Module().(ApexModule); ok {
+		inApex = am.InAnyApex()
+	}
+	isUnbundled := inVendor || (inProduct && isProductUnbundled) || inApex
+
+	// Bundled modules can use any SDK
+	if !isUnbundled {
+		return true
+	}
+
+	// Unbundled modules are allowed to use BOARD_SYSTEMSDK_VERSIONS
+	supportedVersions := ctx.DeviceConfig().SystemSdkVersions()
+
+	// b/314011075: special case for vendor modules. Java modules in the vendor partition can
+	// not use SDK 35 or later. This is to discourage the use of Java APIs in the vendor
+	// partition which hasn't been officially supported since the Project Treble back in Android
+	// 10. We would like to eventually evacuate all Java modules from the partition, but that
+	// shall be done progressively.
+	if inVendor {
+		// 28 was the API when BOARD_SYSTEMSDK_VERSIONS was introduced, so that's the oldest
+		// we should allow.
+		supportedVersions = []string{}
+		for v := 28; v <= 34; v++ {
+			supportedVersions = append(supportedVersions, strconv.Itoa(v))
 		}
 	}
-	if len(allowedVersions) > 0 && !InList(s.ApiLevel.String(), allowedVersions) {
+
+	// APEXes in the system partition are still considered as part of the platform, thus can use
+	// more SDKs from PLATFORM_SYSTEMSDK_VERSIONS
+	if inApex && !inVendor {
+		supportedVersions = ctx.DeviceConfig().PlatformSystemSdkVersions()
+	}
+
+	thisVer, err := s.EffectiveVersion(ctx)
+	if err != nil {
+		ctx.PropertyErrorf("sdk_version", "invalid sdk version %q", s.Raw)
+		return false
+	}
+
+	thisVerString := strconv.Itoa(thisVer.FinalOrPreviewInt())
+	if thisVer.IsPreview() {
+		thisVerString = *ctx.Config().productVariables.Platform_sdk_version_or_codename
+	}
+
+	if !InList(thisVerString, supportedVersions) {
 		ctx.PropertyErrorf("sdk_version", "incompatible sdk version %q. System SDK version should be one of %q",
-			s.Raw, allowedVersions)
+			s.Raw, supportedVersions)
 		return false
 	}
 	return true
 }
 
+func isJava(m Module) bool {
+	moduleType := reflect.TypeOf(m).String()
+	return strings.HasPrefix(moduleType, "*java.")
+}
+
+func isSdkVersion34AvailableIn(c Config) bool {
+	return c.PlatformSdkVersion().FinalInt() >= 34
+}
+
 func init() {
 	RegisterMakeVarsProvider(pctx, javaSdkMakeVars)
 }
diff --git a/android/test_config.go b/android/test_config.go
index 9e1ac70..a15343a 100644
--- a/android/test_config.go
+++ b/android/test_config.go
@@ -39,11 +39,12 @@
 			DeviceName:                          stringPtr("test_device"),
 			DeviceProduct:                       stringPtr("test_product"),
 			Platform_sdk_version:                intPtr(30),
+			Platform_sdk_version_or_codename:    stringPtr("S"),
 			Platform_sdk_codename:               stringPtr("S"),
 			Platform_base_sdk_extension_version: intPtr(1),
 			Platform_version_active_codenames:   []string{"S", "Tiramisu"},
-			DeviceSystemSdkVersions:             []string{"14", "15"},
-			Platform_systemsdk_versions:         []string{"29", "30"},
+			DeviceSystemSdkVersions:             []string{"29", "30", "S"},
+			Platform_systemsdk_versions:         []string{"29", "30", "S", "Tiramisu"},
 			AAPTConfig:                          []string{"normal", "large", "xlarge", "hdpi", "xhdpi", "xxhdpi"},
 			AAPTPreferredConfig:                 stringPtr("xhdpi"),
 			AAPTCharacteristics:                 stringPtr("nosdcard"),
diff --git a/java/Android.bp b/java/Android.bp
index 79cd3f9..2585cd2 100644
--- a/java/Android.bp
+++ b/java/Android.bp
@@ -108,8 +108,9 @@
         "prebuilt_apis_test.go",
         "proto_test.go",
         "rro_test.go",
-        "sdk_test.go",
         "sdk_library_test.go",
+        "sdk_test.go",
+        "sdk_version_test.go",
         "system_modules_test.go",
         "systemserver_classpath_fragment_test.go",
         "test_spec_test.go",
diff --git a/java/sdk_version_test.go b/java/sdk_version_test.go
new file mode 100644
index 0000000..88351d2
--- /dev/null
+++ b/java/sdk_version_test.go
@@ -0,0 +1,66 @@
+// Copyright 2024 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package java
+
+import (
+	"testing"
+
+	"android/soong/android"
+)
+
+func stringPtr(v string) *string {
+	return &v
+}
+
+func TestSystemSdkFromVendor(t *testing.T) {
+	fixtures := android.GroupFixturePreparers(
+		PrepareForTestWithJavaDefaultModules,
+		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
+			variables.Platform_sdk_version = intPtr(34)
+			variables.Platform_sdk_codename = stringPtr("VanillaIceCream")
+			variables.Platform_version_active_codenames = []string{"VanillaIceCream"}
+			variables.Platform_systemsdk_versions = []string{"33", "34", "VanillaIceCream"}
+			variables.DeviceSystemSdkVersions = []string{"VanillaIceCream"}
+		}),
+		FixtureWithPrebuiltApis(map[string][]string{
+			"33": {},
+			"34": {},
+			"35": {},
+		}),
+	)
+
+	fixtures.ExtendWithErrorHandler(android.FixtureExpectsAtLeastOneErrorMatchingPattern("incompatible sdk version")).
+		RunTestWithBp(t, `
+		android_app {
+			name: "foo",
+			srcs: ["a.java"],
+			vendor: true,
+			sdk_version: "system_35",
+		}`)
+
+	result := fixtures.RunTestWithBp(t, `
+		android_app {
+			name: "foo",
+			srcs: ["a.java"],
+			vendor: true,
+			sdk_version: "system_current",
+		}`)
+	fooModule := result.ModuleForTests("foo", "android_common")
+	fooClasspath := fooModule.Rule("javac").Args["classpath"]
+
+	android.AssertStringDoesContain(t, "foo classpath", fooClasspath, "prebuilts/sdk/34/system/android.jar")
+	android.AssertStringDoesNotContain(t, "foo classpath", fooClasspath, "prebuilts/sdk/35/system/android.jar")
+	android.AssertStringDoesNotContain(t, "foo classpath", fooClasspath, "prebuilts/sdk/current/system/android.jar")
+}
diff --git a/sysprop/sysprop_test.go b/sysprop/sysprop_test.go
index e51fe39..e5b3dea 100644
--- a/sysprop/sysprop_test.go
+++ b/sysprop/sysprop_test.go
@@ -125,6 +125,12 @@
 			variables.DeviceSystemSdkVersions = []string{"28"}
 			variables.DeviceVndkVersion = proptools.StringPtr("current")
 			variables.Platform_vndk_version = proptools.StringPtr("29")
+			variables.DeviceCurrentApiLevelForVendorModules = proptools.StringPtr("28")
+		}),
+		java.FixtureWithPrebuiltApis(map[string][]string{
+			"28": {},
+			"29": {},
+			"30": {},
 		}),
 		mockFS.AddToFixture(),
 		android.FixtureWithRootAndroidBp(bp),