Refine CompatChanges check and enable as error.

Because shifting newly written code over to using CompatChanges is
important, this change refines the recently added check and upgrades
it to become a fatal build error.

Bug: 169879376
Test: atest error_prone_android_framework_test
Change-Id: Ic3126518ebaac9995b8f649e44b839de30faa17f

Android.bp

@@ -598,6 +598,11 @@ java_library {
         "//frameworks/base/apex/jobscheduler/framework",
         "//frameworks/base/packages/Tethering/tests/unit",
     ],
+    errorprone: {
+        javacflags: [
+            "-Xep:AndroidFrameworkCompatChange:ERROR",
+        ],
+    },
 }
 
 // This "framework" module is NOT installed to the device. It's

errorprone/java/com/google/errorprone/bugpatterns/android/CompatChangeChecker.java

@@ -17,12 +17,13 @@
 package com.google.errorprone.bugpatterns.android;
 
 import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.bugpatterns.android.TargetSdkChecker.binaryTreeExact;
 import static com.google.errorprone.matchers.FieldMatchers.anyFieldInClass;
 import static com.google.errorprone.matchers.FieldMatchers.staticField;
 import static com.google.errorprone.matchers.Matchers.allOf;
 import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.anything;
-import static com.google.errorprone.matchers.Matchers.binaryTree;
+import static com.google.errorprone.matchers.Matchers.kindIs;
 import static com.google.errorprone.matchers.Matchers.not;
 
 import com.google.auto.service.AutoService;
@@ -34,6 +35,7 @@ import com.google.errorprone.matchers.Description;
 import com.google.errorprone.matchers.Matcher;
 import com.sun.source.tree.BinaryTree;
 import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.Tree.Kind;
 
 /**
  * Each SDK level often has dozens of different behavior changes, which can be
@@ -85,14 +87,28 @@ public final class CompatChangeChecker extends BugChecker implements BinaryTreeM
             staticField("android.os.Build.VERSION_CODES", "O"),
             staticField("android.os.Build.VERSION_CODES", "O_MR1"),
             staticField("android.os.Build.VERSION_CODES", "P"),
-            staticField("android.os.Build.VERSION_CODES", "Q"));
+            staticField("android.os.Build.VERSION_CODES", "Q"),
+            staticField("android.os.Build.VERSION_CODES", "R"));
+
+    private static final Matcher<ExpressionTree> R_VERSION_CODE =
+            staticField("android.os.Build.VERSION_CODES", "R");
+
+    private static final Matcher<ExpressionTree> CUR_DEVELOPMENT_VERSION_CODE =
+            staticField("android.os.Build.VERSION_CODES", "CUR_DEVELOPMENT");
 
     private static final Matcher<ExpressionTree> MODERN_VERSION_CODE =
-            allOf(VERSION_CODE, not(LEGACY_VERSION_CODE));
+            allOf(VERSION_CODE, not(LEGACY_VERSION_CODE), not(CUR_DEVELOPMENT_VERSION_CODE));
+
+    private static final Matcher<ExpressionTree> BOOLEAN_OPERATOR = anyOf(
+            kindIs(Kind.LESS_THAN), kindIs(Kind.LESS_THAN_EQUAL),
+            kindIs(Kind.GREATER_THAN), kindIs(Kind.GREATER_THAN_EQUAL),
+            kindIs(Kind.EQUAL_TO), kindIs(Kind.NOT_EQUAL_TO));
 
     private static final Matcher<BinaryTree> INVALID = anyOf(
-            binaryTree(MODERN_VERSION_CODE, anything()),
-            binaryTree(anything(), MODERN_VERSION_CODE));
+            allOf(BOOLEAN_OPERATOR, binaryTreeExact(MODERN_VERSION_CODE, anything())),
+            allOf(BOOLEAN_OPERATOR, binaryTreeExact(anything(), MODERN_VERSION_CODE)),
+            allOf(kindIs(Kind.GREATER_THAN), binaryTreeExact(anything(), R_VERSION_CODE)),
+            allOf(kindIs(Kind.LESS_THAN), binaryTreeExact(R_VERSION_CODE, anything())));
 
     @Override
     public Description matchBinary(BinaryTree tree, VisitorState state) {

errorprone/java/com/google/errorprone/bugpatterns/android/TargetSdkChecker.java

@@ -89,7 +89,7 @@ public final class TargetSdkChecker extends BugChecker implements BinaryTreeMatc
         return Description.NO_MATCH;
     }
 
-    private static Matcher<BinaryTree> binaryTreeExact(Matcher<ExpressionTree> left,
+    static Matcher<BinaryTree> binaryTreeExact(Matcher<ExpressionTree> left,
             Matcher<ExpressionTree> right) {
         return new Matcher<BinaryTree>() {
             @Override

errorprone/tests/java/com/google/errorprone/bugpatterns/android/CompatChangeCheckerTest.java

@@ -42,17 +42,17 @@ public class CompatChangeCheckerTest {
                         "public class Example {",
                         "  void test(int targetSdkVersion) {",
                         "    // BUG: Diagnostic contains:",
-                        "    if (targetSdkVersion < Build.VERSION_CODES.R) { }",
+                        "    if (targetSdkVersion < Build.VERSION_CODES.S) { }",
                         "    // BUG: Diagnostic contains:",
-                        "    if (targetSdkVersion <= Build.VERSION_CODES.R) { }",
+                        "    if (targetSdkVersion <= Build.VERSION_CODES.S) { }",
                         "    // BUG: Diagnostic contains:",
-                        "    if (targetSdkVersion > Build.VERSION_CODES.R) { }",
+                        "    if (targetSdkVersion > Build.VERSION_CODES.S) { }",
                         "    // BUG: Diagnostic contains:",
-                        "    if (targetSdkVersion >= Build.VERSION_CODES.R) { }",
+                        "    if (targetSdkVersion >= Build.VERSION_CODES.S) { }",
                         "    // BUG: Diagnostic contains:",
-                        "    if (targetSdkVersion == Build.VERSION_CODES.R) { }",
+                        "    if (targetSdkVersion == Build.VERSION_CODES.S) { }",
                         "    // BUG: Diagnostic contains:",
-                        "    if (targetSdkVersion != Build.VERSION_CODES.R) { }",
+                        "    if (targetSdkVersion != Build.VERSION_CODES.S) { }",
                         "  }",
                         "}")
                 .doTest();
@@ -63,18 +63,29 @@ public class CompatChangeCheckerTest {
         compilationHelper
                 .addSourceFile("/android/os/Build.java")
                 .addSourceLines("Example.java",
-                        "import static android.os.Build.VERSION_CODES.R;",
+                        "import android.os.Build;",
+                        "import static android.os.Build.VERSION_CODES.S;",
                         "public class Example {",
                         "  void test(int targetSdkVersion) {",
                         "    // BUG: Diagnostic contains:",
-                        "    boolean indirect = R > targetSdkVersion;",
+                        "    boolean indirect = S >= targetSdkVersion;",
+                        "    // BUG: Diagnostic contains:",
+                        "    if (targetSdkVersion > Build.VERSION_CODES.R) { }",
+                        "    if (targetSdkVersion >= Build.VERSION_CODES.R) { }",
+                        "    if (targetSdkVersion < Build.VERSION_CODES.R) { }",
+                        "    if (targetSdkVersion <= Build.VERSION_CODES.R) { }",
+                        "    // BUG: Diagnostic contains:",
+                        "    if (Build.VERSION_CODES.R < targetSdkVersion) { }",
+                        "    if (Build.VERSION_CODES.R <= targetSdkVersion) { }",
+                        "    if (Build.VERSION_CODES.R > targetSdkVersion) { }",
+                        "    if (Build.VERSION_CODES.R >= targetSdkVersion) { }",
                         "  }",
                         "}")
                 .doTest();
     }
 
     @Test
-    public void testLegacyIgnored() {
+    public void testIgnored() {
         compilationHelper
                 .addSourceFile("/android/os/Build.java")
                 .addSourceLines("Example.java",
@@ -82,6 +93,8 @@ public class CompatChangeCheckerTest {
                         "public class Example {",
                         "  void test(int targetSdkVersion) {",
                         "    if (targetSdkVersion < Build.VERSION_CODES.DONUT) { }",
+                        "    String result = \"test\" + Build.VERSION_CODES.S;",
+                        "    if (targetSdkVersion != Build.VERSION_CODES.CUR_DEVELOPMENT) { }",
                         "  }",
                         "}")
                 .doTest();

errorprone/tests/res/android/os/Build.java

@@ -18,7 +18,9 @@ package android.os;
 
 public class Build {
     public static class VERSION_CODES {
+        public static final int CUR_DEVELOPMENT = 10000;
         public static final int DONUT = 4;
         public static final int R = 30;
+        public static final int S = CUR_DEVELOPMENT;
     }
 }

services/Android.bp

@@ -3,6 +3,11 @@ java_defaults {
     plugins: [
         "error_prone_android_framework",
     ],
+    errorprone: {
+        javacflags: [
+            "-Xep:AndroidFrameworkCompatChange:ERROR",
+        ],
+    },
 }
 
 filegroup {