Use module-lib system modules when building from prebuilts

When building from source the build uses the java system modules for
the public or module APIs as needed. However, previously when building
from prebuilts it would always use the public API. That difference lead
to build failures when building from prebuilts.

This change makes the selection of java system modules when building
from prebuilts consistent with the selection when building from
sources.

As API levels 30 and 31 (which are the only previous releases to
provide system modules) did not provide separate java system modules
for the module-lib API those levels always use the public APIs.

Bug: 204189791
Test: - before applying these change
      m TARGET_BUILD_APPS=framework-connectivity
      - build fails with compilation error due to missing module APIs
      m sdk dist
      cp out/dist/system-modules/module-lib/core-for-system-modules.jar prebuilts/sdk/current/module-lib/core-for-system-modules.jar
      - apply these changes
      m TARGET_BUILD_APPS=framework-connectivity
      - build passes as expected
Change-Id: Id113ff014e7892b1009fbcaad89b1ae23a7c3b79
diff --git a/java/prebuilt_apis_test.go b/java/prebuilt_apis_test.go
index 7c2e526..79f4225 100644
--- a/java/prebuilt_apis_test.go
+++ b/java/prebuilt_apis_test.go
@@ -28,6 +28,7 @@
 		prepareForJavaTest,
 		FixtureWithPrebuiltApis(map[string][]string{
 			"31":      {},
+			"32":      {},
 			"current": {},
 		}),
 	).RunTest(t)
@@ -44,8 +45,11 @@
 		// 31 only has public system modules.
 		"sdk_public_31_system_modules",
 
-		// current only has public system modules.
+		// 32 and current both have public and module-lib system modules.
+		"sdk_public_32_system_modules",
+		"sdk_module-lib_32_system_modules",
 		"sdk_public_current_system_modules",
+		"sdk_module-lib_current_system_modules",
 	}
 	sort.Strings(expected)
 	android.AssertArrayString(t, "sdk system modules", expected, sdkSystemModules)
diff --git a/java/sdk.go b/java/sdk.go
index 42ed14f..34d68ae 100644
--- a/java/sdk.go
+++ b/java/sdk.go
@@ -60,10 +60,28 @@
 	}
 }
 
-// systemModuleKind returns the kind of system modules to use.
-func systemModuleKind() android.SdkKind {
-	// Currently, every sdk version uses the system modules for the public API.
-	return android.SdkPublic
+// systemModuleKind returns the kind of system modules to use for the supplied combination of sdk
+// kind and API level.
+func systemModuleKind(sdkKind android.SdkKind, apiLevel android.ApiLevel) android.SdkKind {
+	systemModuleKind := sdkKind
+	if apiLevel.LessThanOrEqualTo(android.LastWithoutModuleLibCoreSystemModules) {
+		// API levels less than or equal to 31 did not provide a core-for-system-modules.jar
+		// specifically for the module-lib API. So, always use the public system modules for them.
+		systemModuleKind = android.SdkPublic
+	} else if systemModuleKind == android.SdkCore {
+		// Core is by definition what is included in the system module for the public API so should
+		// just use its system modules.
+		systemModuleKind = android.SdkPublic
+	} else if systemModuleKind == android.SdkSystem || systemModuleKind == android.SdkTest {
+		// The core system and test APIs are currently the same as the public API so they should use
+		// its system modules.
+		systemModuleKind = android.SdkPublic
+	} else if systemModuleKind == android.SdkSystemServer {
+		// The core system server API is the same as the core module-lib API.
+		systemModuleKind = android.SdkModule
+	}
+
+	return systemModuleKind
 }
 
 func decodeSdkDep(ctx android.EarlyModuleContext, sdkContext android.SdkContext) sdkDep {
@@ -111,7 +129,7 @@
 
 		var systemModules string
 		if defaultJavaLanguageVersion(ctx, sdkVersion).usesJavaModules() {
-			systemModuleKind := systemModuleKind()
+			systemModuleKind := systemModuleKind(sdkVersion.Kind, sdkVersion.ApiLevel)
 			systemModules = fmt.Sprintf("sdk_%s_%s_system_modules", systemModuleKind, sdkVersion.ApiLevel)
 		}
 
diff --git a/java/sdk_test.go b/java/sdk_test.go
index 9a71192..5c4a6d2 100644
--- a/java/sdk_test.go
+++ b/java/sdk_test.go
@@ -304,7 +304,7 @@
 			name:           "module_current",
 			properties:     `sdk_version: "module_current",`,
 			bootclasspath:  []string{`""`},
-			system:         "sdk_public_current_system_modules",
+			system:         "sdk_module-lib_current_system_modules",
 			java8classpath: []string{"prebuilts/sdk/current/module-lib/android.jar", "prebuilts/sdk/tools/core-lambda-stubs.jar"},
 			java9classpath: []string{"prebuilts/sdk/current/module-lib/android.jar", "prebuilts/sdk/tools/core-lambda-stubs.jar"},
 			aidl:           "-pprebuilts/sdk/current/public/framework.aidl",
@@ -331,7 +331,7 @@
 			name:           "module_32",
 			properties:     `sdk_version: "module_32",`,
 			bootclasspath:  []string{`""`},
-			system:         "sdk_public_32_system_modules",
+			system:         "sdk_module-lib_32_system_modules",
 			java8classpath: []string{"prebuilts/sdk/32/module-lib/android.jar", "prebuilts/sdk/tools/core-lambda-stubs.jar"},
 			java9classpath: []string{"prebuilts/sdk/32/module-lib/android.jar", "prebuilts/sdk/tools/core-lambda-stubs.jar"},
 			aidl:           "-pprebuilts/sdk/32/public/framework.aidl",
@@ -354,7 +354,7 @@
 			name:           "system_server_current",
 			properties:     `sdk_version: "system_server_current",`,
 			bootclasspath:  []string{`""`},
-			system:         "sdk_public_current_system_modules",
+			system:         "sdk_module-lib_current_system_modules",
 			java8classpath: []string{"prebuilts/sdk/current/system-server/android.jar", "prebuilts/sdk/tools/core-lambda-stubs.jar"},
 			java9classpath: []string{"prebuilts/sdk/current/system-server/android.jar", "prebuilts/sdk/tools/core-lambda-stubs.jar"},
 			aidl:           "-pprebuilts/sdk/current/public/framework.aidl",
@@ -381,7 +381,7 @@
 			name:           "system_server_32",
 			properties:     `sdk_version: "system_server_32",`,
 			bootclasspath:  []string{`""`},
-			system:         "sdk_public_32_system_modules",
+			system:         "sdk_module-lib_32_system_modules",
 			java8classpath: []string{"prebuilts/sdk/32/system-server/android.jar", "prebuilts/sdk/tools/core-lambda-stubs.jar"},
 			java9classpath: []string{"prebuilts/sdk/32/system-server/android.jar", "prebuilts/sdk/tools/core-lambda-stubs.jar"},
 			aidl:           "-pprebuilts/sdk/32/public/framework.aidl",
diff --git a/java/testing.go b/java/testing.go
index fafc8d7..3397e46 100644
--- a/java/testing.go
+++ b/java/testing.go
@@ -172,9 +172,10 @@
 
 	fs := make(map[string][]byte)
 	for _, level := range apiLevels {
+		apiLevel := android.ApiLevelForTest(level)
 		for _, sdkKind := range []android.SdkKind{android.SdkPublic, android.SdkSystem, android.SdkModule, android.SdkSystemServer, android.SdkTest} {
 			// A core-for-system-modules file must only be created for the sdk kind that supports it.
-			if sdkKind == systemModuleKind() {
+			if sdkKind == systemModuleKind(sdkKind, apiLevel) {
 				fs[fmt.Sprintf("prebuilts/sdk/%s/%s/core-for-system-modules.jar", level, sdkKind)] = nil
 			}