From 1b3370f5d75e00b074fd7965c5e1d996636879db Mon Sep 17 00:00:00 2001
From: Pete Gillin <peteg@google.com>
Date: Tue, 1 Oct 2019 13:57:31 +0100
Subject: [PATCH] Enable Java language level 9 by default.

This changes the default Java language level from 8 to 9, i.e. javac
invocations now use -source 1.9 -target 1.9.

The environment variable EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9=false is
added to switch back to the language level 8 behaviour. (Previously,
setting that variable to true was required to opt in to language level
9.)

Test: make droid java tests cts docs
Test: javap -v <some class file in output> | grep 'major version' (reports 53, for classes from 'benchmarks' which is in Android.bp and 'ahat' which is in Android.mk)
Test: make RunBluetoothRoboTests RunCarSettingsLibRoboTests (two main flavours of robolectric)
Test: make cts && cts-tradefed help
Test: atest CtsLibcoreTestCases (reasonably low-level device tests)
Test: atest CtsHostTzDataTests (arbitrary host test)
Bug: 115604102
Change-Id: I9de888e1df021244d5e61c40934178676f09ecc7
Merged-In: I52be1817fa7121fca3bce3d8857cb9ed0825570c
---
 android/config.go | 11 ++++++-----
 java/java_test.go | 12 ++++++------
 java/sdk_test.go  | 11 ++++++-----
 3 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/android/config.go b/android/config.go
index 26c4e6ebd..987bcd64c 100644
--- a/android/config.go
+++ b/android/config.go
@@ -386,13 +386,14 @@ func NewConfig(srcDir, buildDir string) (Config, error) {
 
 func (c *config) fromEnv() error {
 	switch c.Getenv("EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9") {
-	case "":
-		// Nothing, this is the default
-	case "true":
-		// Use -source 9 -target 9
+	case "", "true":
+		// Use -source 9 -target 9. This is the default.
 		c.targetOpenJDK9 = true
+	case "false":
+		// Use -source 8 -target 8. This is the legacy behaviour.
+		c.targetOpenJDK9 = false
 	default:
-		return fmt.Errorf(`Invalid value for EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9, should be "" or "true"`)
+		return fmt.Errorf(`Invalid value for EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9, should be "", "true", or "false"`)
 	}
 
 	return nil
diff --git a/java/java_test.go b/java/java_test.go
index f0cb6f8bd..a3499ccd8 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -1095,8 +1095,10 @@ func TestPatchModule(t *testing.T) {
 	`
 
 	t.Run("Java language level 8", func(t *testing.T) {
-		// Test default javac -source 1.8 -target 1.8
-		ctx, _ := testJava(t, bp)
+		// Test with legacy javac -source 1.8 -target 1.8
+		config := testConfig(map[string]string{"EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9": "false"})
+		ctx := testContext(bp, nil)
+		run(t, ctx, config)
 
 		checkPatchModuleFlag(t, ctx, "foo", "")
 		checkPatchModuleFlag(t, ctx, "bar", "")
@@ -1104,10 +1106,8 @@ func TestPatchModule(t *testing.T) {
 	})
 
 	t.Run("Java language level 9", func(t *testing.T) {
-		// Test again with javac -source 9 -target 9
-		config := testConfig(map[string]string{"EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9": "true"})
-		ctx := testContext(bp, nil)
-		run(t, ctx, config)
+		// Test with default javac -source 9 -target 9
+		ctx, _ := testJava(t, bp)
 
 		checkPatchModuleFlag(t, ctx, "foo", "")
 		expected := "java.base=.:" + buildDir
diff --git a/java/sdk_test.go b/java/sdk_test.go
index 5001b477b..5e0e592f6 100644
--- a/java/sdk_test.go
+++ b/java/sdk_test.go
@@ -279,9 +279,9 @@ func TestClasspath(t *testing.T) {
 				}
 			}
 
+			// Test with legacy javac -source 1.8 -target 1.8
 			t.Run("Java language level 8", func(t *testing.T) {
-				// Test default javac -source 1.8 -target 1.8
-				config := testConfig(nil)
+				config := testConfig(map[string]string{"EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9": "false"})
 				if testcase.unbundled {
 					config.TestProductVariables.Unbundled_build = proptools.BoolPtr(true)
 				}
@@ -302,9 +302,9 @@ func TestClasspath(t *testing.T) {
 				}
 			})
 
-			// Test again with javac -source 9 -target 9
+			// Test with default javac -source 9 -target 9
 			t.Run("Java language level 9", func(t *testing.T) {
-				config := testConfig(map[string]string{"EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9": "true"})
+				config := testConfig(nil)
 				if testcase.unbundled {
 					config.TestProductVariables.Unbundled_build = proptools.BoolPtr(true)
 				}
@@ -327,7 +327,8 @@ func TestClasspath(t *testing.T) {
 
 			// Test again with PLATFORM_VERSION_CODENAME=REL
 			t.Run("REL", func(t *testing.T) {
-				config := testConfig(nil)
+				// TODO(b/115604102): This test should be rewritten with language level 9
+				config := testConfig(map[string]string{"EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9": "false"})
 				config.TestProductVariables.Platform_sdk_codename = proptools.StringPtr("REL")
 				config.TestProductVariables.Platform_sdk_final = proptools.BoolPtr(true)