Fix error prone warns

gson/pom.xml

@@ -55,6 +55,11 @@
       <version>31.1-jre</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.google.errorprone</groupId>
+      <artifactId>error_prone_annotations</artifactId>
+      <version>2.18.0</version>
+    </dependency>
   </dependencies>
 
   <build>

gson/src/main/java/com/google/gson/Gson.java

@@ -1011,7 +1011,7 @@ public <T> T fromJson(String json, Class<T> classOfT) throws JsonSyntaxException
    * @see #fromJson(String, Class)
    * @see #fromJson(String, TypeToken)
    */
-  @SuppressWarnings("unchecked")
+  @SuppressWarnings({"unchecked", "TypeParameterUnusedInFormals"})
   public <T> T fromJson(String json, Type typeOfT) throws JsonSyntaxException {
     return (T) fromJson(json, TypeToken.get(typeOfT));
   }
@@ -1104,7 +1104,7 @@ public <T> T fromJson(Reader json, Class<T> classOfT) throws JsonSyntaxException
    * @see #fromJson(Reader, Class)
    * @see #fromJson(Reader, TypeToken)
    */
-  @SuppressWarnings("unchecked")
+  @SuppressWarnings({"unchecked", "TypeParameterUnusedInFormals"})
   public <T> T fromJson(Reader json, Type typeOfT) throws JsonIOException, JsonSyntaxException {
     return (T) fromJson(json, TypeToken.get(typeOfT));
   }
@@ -1183,7 +1183,7 @@ private static void assertFullConsumption(Object obj, JsonReader reader) {
    * @see #fromJson(Reader, Type)
    * @see #fromJson(JsonReader, TypeToken)
    */
-  @SuppressWarnings("unchecked")
+  @SuppressWarnings({"unchecked", "TypeParameterUnusedInFormals"})
   public <T> T fromJson(JsonReader reader, Type typeOfT) throws JsonIOException, JsonSyntaxException {
     return (T) fromJson(reader, TypeToken.get(typeOfT));
   }
@@ -1297,7 +1297,7 @@ public <T> T fromJson(JsonElement json, Class<T> classOfT) throws JsonSyntaxExce
    * @see #fromJson(JsonElement, Class)
    * @see #fromJson(JsonElement, TypeToken)
    */
-  @SuppressWarnings("unchecked")
+  @SuppressWarnings({"unchecked", "TypeParameterUnusedInFormals"})
   public <T> T fromJson(JsonElement json, Type typeOfT) throws JsonSyntaxException {
     return (T) fromJson(json, TypeToken.get(typeOfT));
   }

gson/src/main/java/com/google/gson/JsonDeserializationContext.java

@@ -40,5 +40,6 @@ public interface JsonDeserializationContext {
    * @return An object of type typeOfT.
    * @throws JsonParseException if the parse tree does not contain expected data.
    */
+  @SuppressWarnings("TypeParameterUnusedInFormals")
   public <T> T deserialize(JsonElement json, Type typeOfT) throws JsonParseException;
 }

gson/src/main/java/com/google/gson/JsonParser.java

@@ -15,6 +15,7 @@
  */
 package com.google.gson;
 
+import com.google.errorprone.annotations.InlineMe;
 import com.google.gson.internal.Streams;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonToken;
@@ -111,18 +112,21 @@ public static JsonElement parseReader(JsonReader reader)
 
   /** @deprecated Use {@link JsonParser#parseString} */
   @Deprecated
+  @InlineMe(replacement = "JsonParser.parseString(json)", imports = "com.google.gson.JsonParser")
   public JsonElement parse(String json) throws JsonSyntaxException {
     return parseString(json);
   }
 
   /** @deprecated Use {@link JsonParser#parseReader(Reader)} */
   @Deprecated
+  @InlineMe(replacement = "JsonParser.parseReader(json)", imports = "com.google.gson.JsonParser")
   public JsonElement parse(Reader json) throws JsonIOException, JsonSyntaxException {
     return parseReader(json);
   }
 
   /** @deprecated Use {@link JsonParser#parseReader(JsonReader)} */
   @Deprecated
+  @InlineMe(replacement = "JsonParser.parseReader(json)", imports = "com.google.gson.JsonParser")
   public JsonElement parse(JsonReader json) throws JsonIOException, JsonSyntaxException {
     return parseReader(json);
   }

gson/src/main/java/com/google/gson/internal/JavaVersion.java

@@ -45,7 +45,7 @@ static int getMajorJavaVersion(String javaVersion) {
   // Parses both legacy 1.8 style and newer 9.0.4 style 
   private static int parseDotted(String javaVersion) {
     try {
-      String[] parts = javaVersion.split("[._]");
+      String[] parts = javaVersion.split("[._]", 3);
       int firstVer = Integer.parseInt(parts[0]);
       if (firstVer == 1 && parts.length > 1) {
         return Integer.parseInt(parts[1]);

gson/src/main/java/com/google/gson/internal/bind/ReflectiveTypeAdapterFactory.java

@@ -81,6 +81,7 @@ private boolean includeField(Field f, boolean serialize) {
   }
 
   /** first element holds the default name */
+  @SuppressWarnings("MixedMutabilityReturnType")
   private List<String> getFieldNames(Field f) {
     SerializedName annotation = f.getAnnotation(SerializedName.class);
     if (annotation == null) {

gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java

@@ -174,8 +174,9 @@ private final class GsonContextImpl implements JsonSerializationContext, JsonDes
     @Override public JsonElement serialize(Object src, Type typeOfSrc) {
       return gson.toJsonTree(src, typeOfSrc);
     }
-    @SuppressWarnings("unchecked")
-    @Override public <R> R deserialize(JsonElement json, Type typeOfT) throws JsonParseException {
+    @Override
+    @SuppressWarnings({"unchecked", "TypeParameterUnusedInFormals"})
+    public <R> R deserialize(JsonElement json, Type typeOfT) throws JsonParseException {
       return gson.fromJson(json, typeOfT);
     }
   }

gson/src/main/java/com/google/gson/internal/sql/SqlDateTypeAdapter.java

@@ -36,6 +36,7 @@
  * this class state. DateFormat isn't thread safe either, so this class has
  * to synchronize its read and write methods.
  */
+@SuppressWarnings("JavaUtilDate")
 final class SqlDateTypeAdapter extends TypeAdapter<java.sql.Date> {
   static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
     @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal

gson/src/main/java/com/google/gson/internal/sql/SqlTimeTypeAdapter.java

@@ -37,6 +37,7 @@
  * this class state. DateFormat isn't thread safe either, so this class has
  * to synchronize its read and write methods.
  */
+@SuppressWarnings("JavaUtilDate")
 final class SqlTimeTypeAdapter extends TypeAdapter<Time> {
   static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
     @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal

gson/src/main/java/com/google/gson/internal/sql/SqlTimestampTypeAdapter.java

@@ -27,6 +27,7 @@
 import java.sql.Timestamp;
 import java.util.Date;
 
+@SuppressWarnings("JavaUtilDate")
 class SqlTimestampTypeAdapter extends TypeAdapter<Timestamp> {
   static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
     @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal

gson/src/main/java/com/google/gson/internal/sql/SqlTypesSupport.java

@@ -33,6 +33,7 @@
  * it is {@code false} all other constants will be {@code null} and
  * there will be no support for {@code java.sql} types.
  */
+@SuppressWarnings("JavaUtilDate")
 public final class SqlTypesSupport {
   /**
    * {@code true} if {@code java.sql} types are supported,

gson/src/main/java/com/google/gson/stream/JsonReader.java

@@ -1590,7 +1590,7 @@ public String getPath() {
    * @throws NumberFormatException if any unicode escape sequences are
    *     malformed.
    */
-  @SuppressWarnings("fallthrough")
+  @SuppressWarnings({"fallthrough", "NarrowingCompoundAssignment"})
   private char readEscapeCharacter() throws IOException {
     if (pos == limit && !fillBuffer(1)) {
       throw syntaxError("Unterminated escape sequence");

gson/src/main/java/module-info.java

@@ -24,6 +24,9 @@
   exports com.google.gson.reflect;
   exports com.google.gson.stream;
 
+  // Dependency on Error Prone Annotations
+  requires com.google.errorprone.annotations;
+
   // Optional dependency on java.sql
   requires static java.sql;
 

gson/src/test/java/com/google/gson/ParameterizedTypeFixtures.java

@@ -16,6 +16,7 @@
 
 package com.google.gson;
 
+import com.google.common.base.Objects;
 import com.google.gson.internal.$Gson$Types;
 
 import com.google.gson.internal.Primitives;
@@ -80,27 +81,16 @@ public int hashCode() {
       return value == null ? 0 : value.hashCode();
     }
 
-    @SuppressWarnings("unchecked")
     @Override
     public boolean equals(Object obj) {
       if (this == obj) {
         return true;
       }
-      if (obj == null) {
-        return false;
-      }
-      if (getClass() != obj.getClass()) {
-        return false;
-      }
-      MyParameterizedType<T> other = (MyParameterizedType<T>) obj;
-      if (value == null) {
-        if (other.value != null) {
-          return false;
-        }
-      } else if (!value.equals(other.value)) {
+      if (!(obj instanceof MyParameterizedType<?>)) {
         return false;
       }
-      return true;
+      MyParameterizedType<?> that = (MyParameterizedType<?>) obj;
+      return Objects.equal(getValue(), that.getValue());
     }
   }
 

gson/src/test/java/com/google/gson/VersionExclusionStrategyTest.java

@@ -18,6 +18,7 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
+import com.google.errorprone.annotations.Keep;
 import com.google.gson.annotations.Since;
 import com.google.gson.annotations.Until;
 import com.google.gson.internal.Excluder;
@@ -75,13 +76,15 @@ public void testOlderVersion() throws Exception {
   private static class MockClassSince {
 
     @Since(VERSION)
+    @Keep
     public final int someField = 0;
   }
 
   @Until(VERSION)
   private static class MockClassUntil {
 
     @Until(VERSION)
+    @Keep
     public final int someField = 0;
   }
 
@@ -91,6 +94,7 @@ private static class MockClassBoth {
 
     @Since(VERSION)
     @Until(VERSION + 2)
+    @Keep
     public final int someField = 0;
   }
 }

gson/src/test/java/com/google/gson/common/TestTypes.java

@@ -16,6 +16,7 @@
 
 package com.google.gson.common;
 
+import com.google.common.base.Objects;
 import com.google.gson.JsonDeserializationContext;
 import com.google.gson.JsonDeserializer;
 import com.google.gson.JsonElement;
@@ -146,26 +147,18 @@ public int hashCode() {
     }
 
     @Override
-    public boolean equals(Object obj) {
-      if (this == obj)
+    public boolean equals(Object o) {
+      if (this == o) {
         return true;
-      if (obj == null)
-        return false;
-      if (getClass() != obj.getClass())
-        return false;
-      BagOfPrimitives other = (BagOfPrimitives) obj;
-      if (booleanValue != other.booleanValue)
-        return false;
-      if (intValue != other.intValue)
-        return false;
-      if (longValue != other.longValue)
-        return false;
-      if (stringValue == null) {
-        if (other.stringValue != null)
-          return false;
-      } else if (!stringValue.equals(other.stringValue))
+      }
+      if (!(o instanceof BagOfPrimitives)) {
         return false;
-      return true;
+      }
+      BagOfPrimitives that = (BagOfPrimitives) o;
+      return longValue == that.longValue
+          && getIntValue() == that.getIntValue()
+          && booleanValue == that.booleanValue
+          && Objects.equal(stringValue, that.stringValue);
     }
 
     @Override
@@ -233,7 +226,7 @@ public static class ClassWithNoFields {
     // Nothing here..
     @Override
     public boolean equals(Object other) {
-      return other.getClass() == ClassWithNoFields.class;
+      return other instanceof ClassWithNoFields;
     }
   }
 

gson/src/test/java/com/google/gson/functional/CustomTypeAdaptersTest.java

@@ -425,6 +425,7 @@ public void testEnsureCustomDeserializerNotInvokedForNullValues() {
 
   // Test created from Issue 352
   @Test
+  @SuppressWarnings("JavaUtilDate")
   public void testRegisterHierarchyAdapterForDate() {
     Gson gson = new GsonBuilder()
         .registerTypeHierarchyAdapter(Date.class, new DateTypeAdapter())
@@ -473,6 +474,7 @@ public DataHolder deserialize(JsonElement json, Type typeOfT, JsonDeserializatio
     }
   }
 
+  @SuppressWarnings("JavaUtilDate")
   private static class DateTypeAdapter implements JsonSerializer<Date>, JsonDeserializer<Date> {
     @Override
     public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) {

gson/src/test/java/com/google/gson/functional/DefaultTypeAdaptersTest.java

@@ -68,6 +68,7 @@
  * @author Inderjeet Singh
  * @author Joel Leitch
  */
+@SuppressWarnings("JavaUtilDate")
 public class DefaultTypeAdaptersTest {
   private Gson gson;
   private TimeZone oldTimeZone;

gson/src/test/java/com/google/gson/functional/DelegateTypeAdapterTest.java

@@ -56,7 +56,7 @@ public void testDelegateInvoked() {
       bags.add(new BagOfPrimitives(i, i, i % 2 == 0, String.valueOf(i)));
     }
     String json = gson.toJson(bags);
-    bags = gson.fromJson(json, new TypeToken<List<BagOfPrimitives>>(){}.getType());
+    gson.fromJson(json, new TypeToken<List<BagOfPrimitives>>(){}.getType());
     // 11: 1 list object, and 10 entries. stats invoked on all 5 fields
     assertThat(stats.numReads).isEqualTo(51);
     assertThat(stats.numWrites).isEqualTo(51);
@@ -66,7 +66,7 @@ public void testDelegateInvoked() {
   public void testDelegateInvokedOnStrings() {
     String[] bags = {"1", "2", "3", "4"};
     String json = gson.toJson(bags);
-    bags = gson.fromJson(json, String[].class);
+    gson.fromJson(json, String[].class);
     // 1 array object with 4 elements.
     assertThat(stats.numReads).isEqualTo(5);
     assertThat(stats.numWrites).isEqualTo(5);

gson/src/test/java/com/google/gson/functional/ExposeFieldsTest.java

@@ -18,6 +18,7 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
+import com.google.errorprone.annotations.Keep;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.InstanceCreator;
@@ -121,9 +122,14 @@ public void testExposedInterfaceFieldDeserialization() {
   private static class ClassWithExposedFields {
     @Expose private final Integer a;
     private final Integer b;
-    @Expose(serialize = false) final long c;
-    @Expose(deserialize = false) final double d;
-    @Expose(serialize = false, deserialize = false) final char e;
+    @Expose(serialize = false)
+    @Keep
+    final long c;
+    @Expose(deserialize = false)
+    final double d;
+    @Expose(serialize = false, deserialize = false)
+    @Keep
+    final char e;
 
     public ClassWithExposedFields(Integer a, Integer b) {
       this(a, b, 1L, 2.0, 'a');

gson/src/test/java/com/google/gson/functional/Java17RecordTest.java

@@ -72,6 +72,7 @@ public void testMultipleNamesInTheSameString() {
         .isEqualTo("v3");
   }
 
+  @SuppressWarnings("unused")
   private record RecordWithCustomNames(
       @SerializedName("name") String a,
       @SerializedName(value = "name1", alternate = {"name2", "name3"}) String b) {}
@@ -253,6 +254,7 @@ public void testPrimitiveAdapterNullValue() {
         .isEqualTo("null is not allowed as value for record component 'aByte' of primitive type; at path $.aByte");
   }
 
+  @SuppressWarnings("unused")
   private record RecordWithPrimitives(
       String aString, byte aByte, short aShort, int anInt, long aLong, float aFloat, double aDouble, char aChar, boolean aBoolean) {}
 
@@ -406,7 +408,9 @@ public void testReflectionFilterBlockInaccessible() {
     assertThat(gson.fromJson("{\"i\":2}", PublicRecord.class)).isEqualTo(new PublicRecord(2));
   }
 
+  @SuppressWarnings("unused")
   private record PrivateRecord(int i) {}
+  @SuppressWarnings("unused")
   public record PublicRecord(int i) {}
 
   /**