Merge branch 'master' into strictness2.

Temporarily remove some new deprecations since they cause compilation
failures because of `-Werror`.

Adjust some exception message assertions.

.mvn/jvm.config

@@ -0,0 +1,10 @@
+--add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
+--add-opens jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
+--add-opens jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED

README.md

@@ -59,7 +59,7 @@ see [`GsonBuilder.disableJdkUnsafe()`](https://javadoc.io/doc/com.google.code.gs
   * [API Javadoc](https://www.javadoc.io/doc/com.google.code.gson/gson): Documentation for the current release
   * [User guide](UserGuide.md): This guide contains examples on how to use Gson in your code
   * [Troubleshooting guide](Troubleshooting.md): Describes how to solve common issues when using Gson
-  * [Change log](CHANGELOG.md): Changes in the recent versions
+  * [Releases and change log](https://github.com/google/gson/releases): Latest releases and changes in these versions; for older releases see [`CHANGELOG.md`](CHANGELOG.md)
   * [Design document](GsonDesignDocument.md): This document discusses issues we faced while designing Gson. It also includes a comparison of Gson with other Java libraries that can be used for Json conversion
 
 Please use the ['gson' tag on StackOverflow](https://stackoverflow.com/questions/tagged/gson) or the [google-gson Google group](https://groups.google.com/group/google-gson) to discuss Gson or to post questions.

ReleaseProcess.md

@@ -13,7 +13,7 @@ The following is a step-by-step procedure for releasing a new version of Google-
 1. [Log in to Nexus repository manager](https://oss.sonatype.org/index.html#welcome) at Sonatype and close the staging repository for Gson.
 1. Download and sanity check all downloads. Do not skip this step! Once you release the staging repository, there is no going back. It will get synced with Maven Central and you will not be able to update or delete anything. Your only recourse will be to release a new version of Gson and hope that no one uses the old one.
 1. Release the staging repository for Gson. Gson will now get synced to Maven Central with-in the next hour. For issues consult [Sonatype Guide](https://central.sonatype.org/publish/release/).
-1. Update [Gson Changelog](CHANGELOG.md). Also, look at all bugs that were fixed and add a few lines describing what changed in the release.
+1. Create a [GitHub release](https://github.com/google/gson/releases) for the new version. You can let GitHub [automatically generate the description for the release](https://docs.github.com/en/repositories/releasing-projects-on-github/automatically-generated-release-notes), but you should edit it manually to point out the most important changes and potentially incompatible changes.
 1. Update version references in (version might be referenced multiple times):
     - [`README.md`](README.md)
     - [`UserGuide.md`](UserGuide.md)

UserGuide.md

@@ -135,7 +135,7 @@ BagOfPrimitives obj = new BagOfPrimitives();
 Gson gson = new Gson();
 String json = gson.toJson(obj);
 
-// ==> json is {"value1":1,"value2":"abc"}
+// ==> {"value1":1,"value2":"abc"}
 ```
 
 Note that you can not serialize objects with circular references since that will result in infinite recursion.
@@ -222,7 +222,7 @@ Gson gson = new Gson();
 Collection<Integer> ints = Arrays.asList(1,2,3,4,5);
 
 // Serialization
-String json = gson.toJson(ints);  // ==> json is [1,2,3,4,5]
+String json = gson.toJson(ints);  // ==> [1,2,3,4,5]
 
 // Deserialization
 TypeToken<Collection<Integer>> collectionType = new TypeToken<Collection<Integer>>(){};
@@ -251,14 +251,14 @@ stringMap.put("key", "value");
 stringMap.put(null, "null-entry");
 
 // Serialization
-String json = gson.toJson(stringMap); // ==> json is {"key":"value","null":"null-entry"}
+String json = gson.toJson(stringMap); // ==> {"key":"value","null":"null-entry"}
 
 Map<Integer, Integer> intMap = new LinkedHashMap<>();
 intMap.put(2, 4);
 intMap.put(3, 6);
 
 // Serialization
-String json = gson.toJson(intMap); // ==> json is {"2":4,"3":6}
+String json = gson.toJson(intMap); // ==> {"2":4,"3":6}
 ```
 
 For deserialization Gson uses the `read` method of the `TypeAdapter` registered for the Map key type. Similar to the Collection example shown above, for deserialization a `TypeToken` has to be used to tell Gson what types the Map keys and values have:
@@ -297,12 +297,12 @@ complexMap.put(new PersonName("Jane", "Doe"), 35);
 
 // Serialization; complex map is serialized as a JSON array containing key-value pairs (as JSON arrays)
 String json = gson.toJson(complexMap);
-// ==> json is [[{"firstName":"John","lastName":"Doe"},30],[{"firstName":"Jane","lastName":"Doe"},35]]
+// ==> [[{"firstName":"John","lastName":"Doe"},30],[{"firstName":"Jane","lastName":"Doe"},35]]
 
 Map<String, String> stringMap = new LinkedHashMap<>();
 stringMap.put("key", "value");
 // Serialization; non-complex map is serialized as a regular JSON object
-String json = gson.toJson(stringMap); // json is {"key":"value"}
+String json = gson.toJson(stringMap); // ==> {"key":"value"}
 ```
 
 **Important:** Because Gson by default uses `toString()` to serialize Map keys, this can lead to malformed encoded keys or can cause mismatch between serialization and deserialization of the keys, for example when `toString()` is not properly implemented. A workaround for this can be to use `enableComplexMapKeySerialization()` to make sure the `TypeAdapter` registered for the Map key type is used for deserialization _and_ serialization. As shown in the example above, when none of the keys are serialized by the adapter as JSON array or JSON object, the Map is serialized as a regular JSON object, as desired.
@@ -651,7 +651,6 @@ public class SampleObjectForTest {
   @Foo private final int annotatedField;
   private final String stringField;
   private final long longField;
-  private final Class<?> clazzField;
 
   public SampleObjectForTest() {
     annotatedField = 5;

examples/android-proguard-example/README.md

@@ -6,7 +6,12 @@ or remove them if they appear to be unused. This can cause issues for Gson which
 access the fields of a class. It is necessary to configure ProGuard to make sure that Gson works correctly.
 
 Also have a look at the [ProGuard manual](https://www.guardsquare.com/manual/configuration/usage#keepoverview)
-for more details on how ProGuard can be configured.
+and the [ProGuard Gson examples](https://www.guardsquare.com/manual/configuration/examples#gson) for more
+details on how ProGuard can be configured.
 
 The R8 code shrinker uses the same rule format as ProGuard, but there are differences between these two
 tools. Have a look at R8's Compatibility FAQ, and especially at the [Gson section](https://r8.googlesource.com/r8/+/refs/heads/main/compatibility-faq.md#gson).
+
+Note that newer Gson versions apply some of the rules shown in `proguard.cfg` automatically by default,
+see the file [`gson/META-INF/proguard/gson.pro`](/gson/src/main/resources/META-INF/proguard/gson.pro) for
+the Gson version you are using.

extras/pom.xml

@@ -50,6 +50,7 @@
       <artifactId>jsr250-api</artifactId>
       <version>1.0</version>
     </dependency>
+
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>

extras/src/main/java/com/google/gson/typeadapters/RuntimeTypeAdapterFactory.java

@@ -16,6 +16,7 @@
 
 package com.google.gson.typeadapters;
 
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.gson.Gson;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
@@ -179,6 +180,7 @@ public static <T> RuntimeTypeAdapterFactory<T> of(Class<T> baseType) {
    * Ensures that this factory will handle not just the given {@code baseType}, but any subtype
    * of that type.
    */
+  @CanIgnoreReturnValue
   public RuntimeTypeAdapterFactory<T> recognizeSubtypes() {
     this.recognizeSubtypes = true;
     return this;
@@ -191,6 +193,7 @@ public RuntimeTypeAdapterFactory<T> recognizeSubtypes() {
    * @throws IllegalArgumentException if either {@code type} or {@code label}
    *     have already been registered on this type adapter.
    */
+  @CanIgnoreReturnValue
   public RuntimeTypeAdapterFactory<T> registerSubtype(Class<? extends T> type, String label) {
     if (type == null || label == null) {
       throw new NullPointerException();
@@ -210,6 +213,7 @@ public RuntimeTypeAdapterFactory<T> registerSubtype(Class<? extends T> type, Str
    * @throws IllegalArgumentException if either {@code type} or its simple name
    *     have already been registered on this type adapter.
    */
+  @CanIgnoreReturnValue
   public RuntimeTypeAdapterFactory<T> registerSubtype(Class<? extends T> type) {
     return registerSubtype(type, type.getSimpleName());
   }

extras/src/main/java/com/google/gson/typeadapters/UtcDateTypeAdapter.java

@@ -62,7 +62,7 @@ public Date read(JsonReader in) throws IOException {
   }
 
   // Date parsing code from Jackson databind ISO8601Utils.java
-  // https://github.com/FasterXML/jackson-databind/blob/master/src/main/java/com/fasterxml/jackson/databind/util/ISO8601Utils.java
+  // https://github.com/FasterXML/jackson-databind/blob/2.8/src/main/java/com/fasterxml/jackson/databind/util/ISO8601Utils.java
   private static final String GMT_ID = "GMT";
 
   /**

extras/src/test/java/com/google/gson/graph/GraphAdapterBuilderTest.java

@@ -129,8 +129,9 @@ public void testDeserializeListOfLists() {
   @Test
   public void testSerializationWithMultipleTypes() {
     Company google = new Company("Google");
-    new Employee("Jesse", google);
-    new Employee("Joel", google);
+    // Employee constructor adds `this` to the given Company object
+    Employee unused1 = new Employee("Jesse", google);
+    Employee unused2 = new Employee("Joel", google);
 
     GsonBuilder gsonBuilder = new GsonBuilder();
     new GraphAdapterBuilder()

extras/src/test/java/com/google/gson/interceptors/InterceptorTest.java

@@ -110,9 +110,9 @@ public void testCustomTypeAdapter() {
 
           @Override public User read(JsonReader in) throws IOException {
             in.beginObject();
-            in.nextName();
+            String unused1 = in.nextName();
             String name = in.nextString();
-            in.nextName();
+            String unused2 = in.nextName();
             String password = in.nextString();
             in.endObject();
             return new User(name, password);

extras/src/test/java/com/google/gson/typeadapters/UtcDateTypeAdapterTest.java

@@ -64,7 +64,7 @@ public void testUtcDatesOnJdkBefore1_7() {
     Gson gson = new GsonBuilder()
       .registerTypeAdapter(Date.class, new UtcDateTypeAdapter())
       .create();
-    gson.fromJson("'2014-12-05T04:00:00.000Z'", Date.class);
+    Date unused = gson.fromJson("'2014-12-05T04:00:00.000Z'", Date.class);
   }
 
   @Test

gson/pom.xml

@@ -38,6 +38,17 @@
   </properties>
 
   <dependencies>
+    <!-- This dependency can be considered optional; omitting it during runtime will most likely
+      not cause any issues. However, it is not declared with `<optional>true</optional>` because
+      that can lead to cryptic compiler warnings for consumers, and to be on the safe side in case
+      there are actually issues which could occur when the dependency is missing at runtime.
+      See also discussion at https://github.com/google/gson/pull/2320#issuecomment-1455233938 -->
+    <dependency>
+      <groupId>com.google.errorprone</groupId>
+      <artifactId>error_prone_annotations</artifactId>
+      <version>2.19.1</version>
+    </dependency>
+
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
@@ -46,21 +57,14 @@
     <dependency>
       <groupId>com.google.truth</groupId>
       <artifactId>truth</artifactId>
-      <version>1.1.3</version>
       <scope>test</scope>
     </dependency>
     <dependency>
       <groupId>com.google.guava</groupId>
       <artifactId>guava-testlib</artifactId>
-      <version>31.1-jre</version>
+      <version>32.0.0-jre</version>
       <scope>test</scope>
     </dependency>
-    <dependency>
-      <groupId>com.google.errorprone</groupId>
-      <artifactId>error_prone_annotations</artifactId>
-      <version>2.18.0</version>
-      <optional>true</optional>
-    </dependency>
   </dependencies>
 
   <build>
@@ -79,7 +83,7 @@
               <goal>filter-sources</goal>
             </goals>
             <configuration>
-              <sourceDirectory>${basedir}/src/main/java-templates</sourceDirectory>
+              <sourceDirectory>${project.basedir}/src/main/java-templates</sourceDirectory>
               <outputDirectory>${project.build.directory}/generated-sources/java-templates</outputDirectory>
             </configuration>
           </execution>
@@ -131,7 +135,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
-        <version>3.0.0-M9</version>
+        <version>3.1.0</version>
         <configuration>
           <!-- Deny illegal access, this is required for ReflectionAccessTest -->
           <!-- Requires Java >= 9; Important: In case future Java versions 
@@ -187,7 +191,7 @@
           <injar>test-classes-obfuscated-injar</injar>
           <outjar>test-classes-obfuscated-outjar</outjar>
           <inFilter>**/*.class</inFilter>
-          <proguardInclude>${basedir}/src/test/resources/testcases-proguard.conf</proguardInclude>
+          <proguardInclude>${project.basedir}/src/test/resources/testcases-proguard.conf</proguardInclude>
           <libs>
             <lib>${project.build.directory}/classes</lib>
             <lib>${java.home}/jmods/java.base.jmod</lib>
@@ -196,7 +200,7 @@
       </plugin>
       <plugin>
         <artifactId>maven-resources-plugin</artifactId>
-        <version>3.3.0</version>
+        <version>3.3.1</version>
         <executions>
           <execution>
             <id>post-obfuscate-class</id>
@@ -241,7 +245,7 @@
       <plugin>
         <groupId>org.moditect</groupId>
         <artifactId>moditect-maven-plugin</artifactId>
-        <version>1.0.0.RC2</version>
+        <version>1.0.0.Final</version>
         <executions>
           <execution>
             <id>add-module-info</id>