Enable additional Error Prone checks & fix violations (#2561)

* Enable additional Error Prone checks & fix violations Some of them also enforce additional Google Java Format requirements which are not handled by google-java-format, such as disallowing wildcard imports. Not all experimental checks have been listed because some are not applicable, such as Dependency Injection framework checks, or checks related to Guava's immutable collections (since Gson's main code does not have a dependency on Guava). Other checks have been omitted because they are probably not relevant (this was a subjective choice), or would require larger refactoring or would flag issues with the public API, which cannot be changed easily. * Address review feedback --------- Co-authored-by: Éamonn McManus <[email protected]>
google · Jan 9, 2024 · 5187808 · 5187808
1 parent 2bcaaed
commit 5187808
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diff --git a/...s/src/main/java/com/google/gson/extras/examples/rawcollections/RawCollectionsExample.java b/...s/src/main/java/com/google/gson/extras/examples/rawcollections/RawCollectionsExample.java
@@ -21,6 +21,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 
+@SuppressWarnings({"PrivateConstructorForUtilityClass", "SystemOut"})
 public class RawCollectionsExample {
   static class Event {
     private String name;

diff --git a/extras/src/main/java/com/google/gson/typeadapters/PostConstructAdapterFactory.java b/extras/src/main/java/com/google/gson/typeadapters/PostConstructAdapterFactory.java
@@ -61,9 +61,11 @@ public T read(JsonReader in) throws IOException {
         try {
           method.invoke(result);
         } catch (IllegalAccessException e) {
-          throw new AssertionError();
+          throw new AssertionError(e);
         } catch (InvocationTargetException e) {
-          if (e.getCause() instanceof RuntimeException) throw (RuntimeException) e.getCause();
+          if (e.getCause() instanceof RuntimeException) {
+            throw (RuntimeException) e.getCause();
+          }
           throw new RuntimeException(e.getCause());
         }
       }

diff --git a/extras/src/main/java/com/google/gson/typeadapters/UtcDateTypeAdapter.java b/extras/src/main/java/com/google/gson/typeadapters/UtcDateTypeAdapter.java
@@ -30,7 +30,7 @@
 import java.util.TimeZone;
 
 public final class UtcDateTypeAdapter extends TypeAdapter<Date> {
-  private final TimeZone UTC_TIME_ZONE = TimeZone.getTimeZone("UTC");
+  private static final TimeZone UTC_TIME_ZONE = TimeZone.getTimeZone("UTC");
 
   @Override
   public void write(JsonWriter out, Date date) throws IOException {

diff --git a/extras/src/test/java/com/google/gson/interceptors/InterceptorTest.java b/extras/src/test/java/com/google/gson/interceptors/InterceptorTest.java
@@ -171,7 +171,9 @@ public void postDeserialize(User user) {
       if (user.name == null || user.password == null) {
         throw new JsonSyntaxException("name and password are required fields.");
       }
-      if (user.email == null) user.email = User.DEFAULT_EMAIL;
+      if (user.email == null) {
+        user.email = User.DEFAULT_EMAIL;
+      }
     }
   }
 
@@ -192,7 +194,9 @@ public void postDeserialize(Address address) {
       if (address.city == null || address.state == null || address.zip == null) {
         throw new JsonSyntaxException("Address city, state and zip are required fields.");
       }
-      if (address.firstLine == null) address.firstLine = Address.DEFAULT_FIRST_LINE;
+      if (address.firstLine == null) {
+        address.firstLine = Address.DEFAULT_FIRST_LINE;
+      }
     }
   }
 }
diff --git a/gson/src/main/java/com/google/gson/Gson.java b/gson/src/main/java/com/google/gson/Gson.java
@@ -656,6 +656,16 @@ public <T> TypeAdapter<T> getAdapter(TypeToken<T> type) {
     return candidate;
   }
 
+  /**
+   * Returns the type adapter for {@code type}.
+   *
+   * @throws IllegalArgumentException if this Gson instance cannot serialize and deserialize {@code
+   *     type}.
+   */
+  public <T> TypeAdapter<T> getAdapter(Class<T> type) {
+    return getAdapter(TypeToken.get(type));
+  }
+
   /**
    * This method is used to get an alternate type adapter for the specified type. This is used to
    * access a type adapter that is overridden by a {@link TypeAdapterFactory} that you may have
@@ -748,16 +758,6 @@ public <T> TypeAdapter<T> getDelegateAdapter(TypeAdapterFactory skipPast, TypeTo
     }
   }
 
-  /**
-   * Returns the type adapter for {@code type}.
-   *
-   * @throws IllegalArgumentException if this Gson instance cannot serialize and deserialize {@code
-   *     type}.
-   */
-  public <T> TypeAdapter<T> getAdapter(Class<T> type) {
-    return getAdapter(TypeToken.get(type));
-  }
-
   /**
    * This method serializes the specified object into its equivalent representation as a tree of
    * {@link JsonElement}s. This method should be used when the specified object is not a generic
@@ -983,53 +983,6 @@ public void toJson(JsonElement jsonElement, Appendable writer) throws JsonIOExce
     }
   }
 
-  /**
-   * Returns a new JSON writer configured for the settings on this Gson instance.
-   *
-   * <p>The following settings are considered:
-   *
-   * <ul>
-   *   <li>{@link GsonBuilder#disableHtmlEscaping()}
-   *   <li>{@link GsonBuilder#generateNonExecutableJson()}
-   *   <li>{@link GsonBuilder#serializeNulls()}
-   *   <li>{@link GsonBuilder#setStrictness(Strictness)}. If no {@linkplain
-   *       GsonBuilder#setStrictness(Strictness) explicit strictness has been set} the created
-   *       writer will have a strictness of {@link Strictness#LEGACY_STRICT}. Otherwise, the
-   *       strictness of the {@code Gson} instance will be used for the created writer.
-   *   <li>{@link GsonBuilder#setPrettyPrinting()}
-   *   <li>{@link GsonBuilder#setFormattingStyle(FormattingStyle)}
-   * </ul>
-   */
-  public JsonWriter newJsonWriter(Writer writer) throws IOException {
-    if (generateNonExecutableJson) {
-      writer.write(JSON_NON_EXECUTABLE_PREFIX);
-    }
-    JsonWriter jsonWriter = new JsonWriter(writer);
-    jsonWriter.setFormattingStyle(formattingStyle);
-    jsonWriter.setHtmlSafe(htmlSafe);
-    jsonWriter.setStrictness(strictness == null ? Strictness.LEGACY_STRICT : strictness);
-    jsonWriter.setSerializeNulls(serializeNulls);
-    return jsonWriter;
-  }
-
-  /**
-   * Returns a new JSON reader configured for the settings on this Gson instance.
-   *
-   * <p>The following settings are considered:
-   *
-   * <ul>
-   *   <li>{@link GsonBuilder#setStrictness(Strictness)}. If no {@linkplain
-   *       GsonBuilder#setStrictness(Strictness) explicit strictness has been set} the created
-   *       reader will have a strictness of {@link Strictness#LEGACY_STRICT}. Otherwise, the
-   *       strictness of the {@code Gson} instance will be used for the created reader.
-   * </ul>
-   */
-  public JsonReader newJsonReader(Reader reader) {
-    JsonReader jsonReader = new JsonReader(reader);
-    jsonReader.setStrictness(strictness == null ? Strictness.LEGACY_STRICT : strictness);
-    return jsonReader;
-  }
-
   /**
    * Writes the JSON for {@code jsonElement} to {@code writer}.
    *
@@ -1078,6 +1031,53 @@ public void toJson(JsonElement jsonElement, JsonWriter writer) throws JsonIOExce
     }
   }
 
+  /**
+   * Returns a new JSON writer configured for the settings on this Gson instance.
+   *
+   * <p>The following settings are considered:
+   *
+   * <ul>
+   *   <li>{@link GsonBuilder#disableHtmlEscaping()}
+   *   <li>{@link GsonBuilder#generateNonExecutableJson()}
+   *   <li>{@link GsonBuilder#serializeNulls()}
+   *   <li>{@link GsonBuilder#setStrictness(Strictness)}. If no {@linkplain
+   *       GsonBuilder#setStrictness(Strictness) explicit strictness has been set} the created
+   *       writer will have a strictness of {@link Strictness#LEGACY_STRICT}. Otherwise, the
+   *       strictness of the {@code Gson} instance will be used for the created writer.
+   *   <li>{@link GsonBuilder#setPrettyPrinting()}
+   *   <li>{@link GsonBuilder#setFormattingStyle(FormattingStyle)}
+   * </ul>
+   */
+  public JsonWriter newJsonWriter(Writer writer) throws IOException {
+    if (generateNonExecutableJson) {
+      writer.write(JSON_NON_EXECUTABLE_PREFIX);
+    }
+    JsonWriter jsonWriter = new JsonWriter(writer);
+    jsonWriter.setFormattingStyle(formattingStyle);
+    jsonWriter.setHtmlSafe(htmlSafe);
+    jsonWriter.setStrictness(strictness == null ? Strictness.LEGACY_STRICT : strictness);
+    jsonWriter.setSerializeNulls(serializeNulls);
+    return jsonWriter;
+  }
+
+  /**
+   * Returns a new JSON reader configured for the settings on this Gson instance.
+   *
+   * <p>The following settings are considered:
+   *
+   * <ul>
+   *   <li>{@link GsonBuilder#setStrictness(Strictness)}. If no {@linkplain
+   *       GsonBuilder#setStrictness(Strictness) explicit strictness has been set} the created
+   *       reader will have a strictness of {@link Strictness#LEGACY_STRICT}. Otherwise, the
+   *       strictness of the {@code Gson} instance will be used for the created reader.
+   * </ul>
+   */
+  public JsonReader newJsonReader(Reader reader) {
+    JsonReader jsonReader = new JsonReader(reader);
+    jsonReader.setStrictness(strictness == null ? Strictness.LEGACY_STRICT : strictness);
+    return jsonReader;
+  }
+
   /**
    * This method deserializes the specified JSON into an object of the specified class. It is not
    * suitable to use if the specified class is a generic type since it will not have the generic
@@ -1262,18 +1262,6 @@ public <T> T fromJson(Reader json, TypeToken<T> typeOfT)
     return object;
   }
 
-  private static void assertFullConsumption(Object obj, JsonReader reader) {
-    try {
-      if (obj != null && reader.peek() != JsonToken.END_DOCUMENT) {
-        throw new JsonSyntaxException("JSON document was not fully consumed.");
-      }
-    } catch (MalformedJsonException e) {
-      throw new JsonSyntaxException(e);
-    } catch (IOException e) {
-      throw new JsonIOException(e);
-    }
-  }
-
   // fromJson(JsonReader, Class) is unfortunately missing and cannot be added now without breaking
   // source compatibility in certain cases, see
   // https://github.com/google/gson/pull/1700#discussion_r973764414
@@ -1472,6 +1460,18 @@ public <T> T fromJson(JsonElement json, TypeToken<T> typeOfT) throws JsonSyntaxE
     return fromJson(new JsonTreeReader(json), typeOfT);
   }
 
+  private static void assertFullConsumption(Object obj, JsonReader reader) {
+    try {
+      if (obj != null && reader.peek() != JsonToken.END_DOCUMENT) {
+        throw new JsonSyntaxException("JSON document was not fully consumed.");
+      }
+    } catch (MalformedJsonException e) {
+      throw new JsonSyntaxException(e);
+    } catch (IOException e) {
+      throw new JsonIOException(e);
+    }
+  }
+
   /**
    * Proxy type adapter for cyclic type graphs.
    *

diff --git a/gson/src/main/java/com/google/gson/GsonBuilder.java b/gson/src/main/java/com/google/gson/GsonBuilder.java
@@ -614,14 +614,6 @@ public GsonBuilder setDateFormat(String pattern) {
     return this;
   }
 
-  private static int checkDateFormatStyle(int style) {
-    // Valid DateFormat styles are: 0, 1, 2, 3 (FULL, LONG, MEDIUM, SHORT)
-    if (style < 0 || style > 3) {
-      throw new IllegalArgumentException("Invalid style: " + style);
-    }
-    return style;
-  }
-
   /**
    * Configures Gson to serialize {@code Date} objects according to the date style value provided.
    * You can call this method or {@link #setDateFormat(String)} multiple times, but only the last
@@ -669,6 +661,14 @@ public GsonBuilder setDateFormat(int dateStyle, int timeStyle) {
     return this;
   }
 
+  private static int checkDateFormatStyle(int style) {
+    // Valid DateFormat styles are: 0, 1, 2, 3 (FULL, LONG, MEDIUM, SHORT)
+    if (style < 0 || style > 3) {
+      throw new IllegalArgumentException("Invalid style: " + style);
+    }
+    return style;
+  }
+
   /**
    * Configures Gson for custom serialization or deserialization. This method combines the
    * registration of an {@link TypeAdapter}, {@link InstanceCreator}, {@link JsonSerializer}, and a
@@ -722,7 +722,7 @@ public GsonBuilder registerTypeAdapter(Type type, Object typeAdapter) {
     return this;
   }
 
-  private boolean isTypeObjectOrJsonElement(Type type) {
+  private static boolean isTypeObjectOrJsonElement(Type type) {
     return type instanceof Class
         && (type == Object.class || JsonElement.class.isAssignableFrom((Class<?>) type));
   }
@@ -901,7 +901,7 @@ public Gson create() {
         new ArrayList<>(reflectionFilters));
   }
 
-  private void addTypeAdaptersForDate(
+  private static void addTypeAdaptersForDate(
       String datePattern, int dateStyle, int timeStyle, List<TypeAdapterFactory> factories) {
     TypeAdapterFactory dateAdapterFactory;
     boolean sqlTypesSupported = SqlTypesSupport.SUPPORTS_SQL_TYPES;

diff --git a/gson/src/main/java/com/google/gson/JsonPrimitive.java b/gson/src/main/java/com/google/gson/JsonPrimitive.java
@@ -38,7 +38,10 @@ public final class JsonPrimitive extends JsonElement {
    *
    * @param bool the value to create the primitive with.
    */
-  @SuppressWarnings("deprecation") // superclass constructor
+  // "deprecation" suppression for superclass constructor
+  // "UnnecessaryBoxedVariable" Error Prone warning is correct since method does not accept
+  // null, but cannot be changed anymore since this is public API
+  @SuppressWarnings({"deprecation", "UnnecessaryBoxedVariable"})
   public JsonPrimitive(Boolean bool) {
     value = Objects.requireNonNull(bool);
   }
@@ -69,7 +72,10 @@ public JsonPrimitive(String string) {
    *
    * @param c the value to create the primitive with.
    */
-  @SuppressWarnings("deprecation") // superclass constructor
+  // "deprecation" suppression for superclass constructor
+  // "UnnecessaryBoxedVariable" Error Prone warning is correct since method does not accept
+  // null, but cannot be changed anymore since this is public API
+  @SuppressWarnings({"deprecation", "UnnecessaryBoxedVariable"})
   public JsonPrimitive(Character c) {
     // convert characters to strings since in JSON, characters are represented as a single
     // character string