Adjust declarative config pojo toString, hashCode, equals to match autovalue (#8526)

Author: jack-berg

buildSrc/build.gradle.kts

@@ -49,6 +49,7 @@ dependencies {
   implementation("net.ltgt.gradle:gradle-errorprone-plugin:5.1.0")
   implementation("net.ltgt.gradle:gradle-nullaway-plugin:3.1.0")
   implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:2.3.21")
+  implementation("org.jsonschema2pojo:jsonschema2pojo-core:1.3.3")
   implementation("org.sonatype.gradle.plugins:scan-gradle-plugin:3.1.6")
   implementation("ru.vyarus:gradle-animalsniffer-plugin:2.0.1")
 }

buildSrc/src/main/java/io/opentelemetry/gradle/js2p/NullableAnnotator.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.gradle.js2p;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.sun.codemodel.JDefinedClass;
+import com.sun.codemodel.JFieldVar;
+import com.sun.codemodel.JMethod;
+import javax.annotation.Nullable;
+import org.jsonschema2pojo.AbstractAnnotator;
+
+/**
+ * Annotates every generated property field and getter with {@code @Nullable}.
+ *
+ * <p>jsonschema2pojo's built-in JSR-305 support ({@code includeJsr305Annotations}) annotates
+ * required fields with {@code @Nonnull} and optional fields with {@code @Nullable}. The {@code
+ * @Nonnull} fields are never initialized (Jackson populates them reflectively), which makes NullAway
+ * flag them as uninitialized {@code @NonNull} fields. Since the generated getters are uniformly
+ * {@code @Nullable} anyway and field presence is validated at runtime by the model factories, we
+ * disable {@code includeJsr305Annotations} and instead annotate everything {@code @Nullable} here.
+ */
+public class NullableAnnotator extends AbstractAnnotator {
+
+  @Override
+  public void propertyField(
+      JFieldVar field, JDefinedClass clazz, String propertyName, JsonNode propertyNode) {
+    field.annotate(Nullable.class);
+  }
+
+  @Override
+  public void propertyGetter(JMethod getter, JDefinedClass clazz, String propertyName) {
+    getter.annotate(Nullable.class);
+  }
+
+  @Override
+  public boolean isPolymorphicDeserializationSupported(JsonNode node) {
+    // Defer to the composed Jackson annotator rather than vetoing polymorphic deserialization.
+    return true;
+  }
+}

buildSrc/src/main/java/io/opentelemetry/gradle/js2p/OtelObjectRule.java

@@ -0,0 +1,134 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.gradle.js2p;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.sun.codemodel.ClassType;
+import com.sun.codemodel.JBlock;
+import com.sun.codemodel.JCodeModel;
+import com.sun.codemodel.JDefinedClass;
+import com.sun.codemodel.JExpr;
+import com.sun.codemodel.JFieldVar;
+import com.sun.codemodel.JMethod;
+import com.sun.codemodel.JMod;
+import com.sun.codemodel.JPackage;
+import com.sun.codemodel.JType;
+import com.sun.codemodel.JVar;
+import javax.annotation.Nullable;
+import org.jsonschema2pojo.Schema;
+import org.jsonschema2pojo.rules.ObjectRule;
+import org.jsonschema2pojo.rules.RuleFactory;
+import org.jsonschema2pojo.util.ParcelableHelper;
+import org.jsonschema2pojo.util.ReflectionHelper;
+
+/**
+ * An {@link ObjectRule} that replaces jsonschema2pojo's generated {@code toString}/{@code
+ * equals}/{@code hashCode} with implementations that mirror AutoValue's style.
+ */
+public class OtelObjectRule extends ObjectRule {
+
+  public OtelObjectRule(
+      RuleFactory ruleFactory,
+      ParcelableHelper parcelableHelper,
+      ReflectionHelper reflectionHelper) {
+    super(ruleFactory, parcelableHelper, reflectionHelper);
+  }
+
+  @Override
+  public JType apply(
+      String nodeName, JsonNode node, JsonNode parent, JPackage pkg, Schema schema) {
+    JType type = super.apply(nodeName, node, parent, pkg, schema);
+    if (type instanceof JDefinedClass
+        && ((JDefinedClass) type).getClassType() == ClassType.CLASS) {
+      addValueMethods((JDefinedClass) type);
+    }
+    return type;
+  }
+
+  private static void addValueMethods(JDefinedClass clazz) {
+    JCodeModel model = clazz.owner();
+
+    addToString(clazz, model);
+    addHashCode(clazz, model);
+    addEquals(clazz, model);
+  }
+
+  // toString: ClassName{field1=value1, field2=value2}
+  private static void addToString(JDefinedClass clazz, JCodeModel model) {
+    JMethod toString = clazz.method(JMod.PUBLIC, model.ref(String.class), "toString");
+    toString.annotate(Override.class);
+
+    StringBuilder expr = new StringBuilder("return \"").append(clazz.name()).append("{\"");
+    boolean first = true;
+    for (JFieldVar field : clazz.fields().values()) {
+      if (isStatic(field)) {
+        continue;
+      }
+      expr.append(" + \"")
+          .append(first ? "" : ", ")
+          .append(field.name())
+          .append("=\" + ")
+          .append(field.name());
+      first = false;
+    }
+    expr.append(" + \"}\";");
+    toString.body().directStatement(expr.toString());
+  }
+
+  // equals: instanceof + cast + (this.f == null ? that.f == null : this.f.equals(that.f)) && ...
+  private static void addEquals(JDefinedClass clazz, JCodeModel model) {
+    JMethod equals = clazz.method(JMod.PUBLIC, model.BOOLEAN, "equals");
+    equals.annotate(Override.class);
+    JVar other = equals.param(model.ref(Object.class), "o");
+    other.annotate(Nullable.class);
+    JBlock body = equals.body();
+
+    body._if(other.eq(JExpr._this()))._then()._return(JExpr.TRUE);
+
+    JBlock matched = body._if(other._instanceof(clazz))._then();
+    matched.directStatement(clazz.name() + " that = (" + clazz.name() + ") o;");
+
+    StringBuilder comparison = new StringBuilder("return ");
+    boolean first = true;
+    for (JFieldVar field : clazz.fields().values()) {
+      if (isStatic(field)) {
+        continue;
+      }
+      String name = field.name();
+      comparison
+          .append(first ? "" : " && ")
+          .append("(this.").append(name).append(" == null ? that.").append(name)
+          .append(" == null : this.").append(name).append(".equals(that.").append(name)
+          .append("))");
+      first = false;
+    }
+    matched.directStatement(first ? "return true;" : comparison.append(";").toString());
+
+    body._return(JExpr.FALSE);
+  }
+
+  // hashCode: h = 1; h *= 1000003; h ^= (f == null ? 0 : f.hashCode()); ...
+  private static void addHashCode(JDefinedClass clazz, JCodeModel model) {
+    JMethod hashCode = clazz.method(JMod.PUBLIC, model.INT, "hashCode");
+    hashCode.annotate(Override.class);
+    JBlock body = hashCode.body();
+    JVar h = body.decl(model.INT, "h", JExpr.lit(1));
+
+    for (JFieldVar field : clazz.fields().values()) {
+      if (isStatic(field)) {
+        continue;
+      }
+      String name = field.name();
+      body.directStatement("h *= 1000003;");
+      body.directStatement("h ^= (this." + name + " == null) ? 0 : this." + name + ".hashCode();");
+    }
+    body._return(h);
+  }
+
+  private static boolean isStatic(JFieldVar field) {
+    return (field.mods().getValue() & JMod.STATIC) == JMod.STATIC;
+  }
+}

buildSrc/src/main/java/io/opentelemetry/gradle/js2p/OtelRuleFactory.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.gradle.js2p;
+
+import com.sun.codemodel.JPackage;
+import com.sun.codemodel.JType;
+import org.jsonschema2pojo.rules.ObjectRule;
+import org.jsonschema2pojo.rules.Rule;
+import org.jsonschema2pojo.rules.RuleFactory;
+import org.jsonschema2pojo.util.ParcelableHelper;
+
+/**
+ * Custom {@link RuleFactory} that swaps in {@link OtelObjectRule} so generated POJOs get
+ * AutoValue-style {@code toString}/{@code equals}/{@code hashCode} implementations instead of
+ * jsonschema2pojo's defaults.
+ *
+ * <p>Referenced from {@code sdk-extensions/declarative-config/build.gradle.kts} via {@code
+ * jsonSchema2Pojo.customRuleFactory}.
+ */
+public class OtelRuleFactory extends RuleFactory {
+
+  @Override
+  public Rule<JPackage, JType> getObjectRule() {
+    return new OtelObjectRule(this, new ParcelableHelper(), getReflectionHelper());
+  }
+}

sdk-extensions/declarative-config/build.gradle.kts

@@ -47,6 +47,7 @@ dependencies {
   testImplementation("com.linecorp.armeria:armeria-junit5")
 //
   testImplementation("com.google.guava:guava-testlib")
+  testImplementation("nl.jqno.equalsverifier:equalsverifier")
 }
 
 // The following tasks download the JSON Schema files from open-telemetry/opentelemetry-configuration,
@@ -100,9 +101,20 @@ jsonSchema2Pojo {
   // Clear old source files to avoid contaminated source dir when updating
   removeOldOutput = true
 
-  // Include @Nullable annotation. Note: jsonSchema2Pojo will not add @Nullable annotations on getters
-  // so we add these in syncPojoModelsToSrc.
-  includeJsr305Annotations = true
+  // Annotate fields/getters via NullableAnnotator instead of jsonschema2pojo's JSR-305 support. The
+  // built-in support adds @Nonnull to required fields, which NullAway flags as uninitialized (Jackson
+  // populates them reflectively). NullableAnnotator annotates everything @Nullable instead, matching
+  // the getters and letting the model factories validate required-ness at runtime.
+  includeJsr305Annotations = false
+  setCustomAnnotator(io.opentelemetry.gradle.js2p.NullableAnnotator::class.java)
+
+  // Generate AutoValue-style toString/equals/hashCode via OtelObjectRule (wired through
+  // OtelRuleFactory) rather than jsonschema2pojo's defaults. The defaults use a commons-style
+  // toString (System.identityHashCode) and compare boxed fields with == (tripping ErrorProne's
+  // BoxedPrimitiveEquality). Disable the built-in generation so the custom rule can supply its own.
+  includeToString = false
+  includeHashcodeAndEquals = false
+  setCustomRuleFactory(io.opentelemetry.gradle.js2p.OtelRuleFactory::class.java)
 
   // Prefer builders to setters
   includeSetters = false
@@ -146,22 +158,8 @@ val syncPojoModelsToSrc by tasks.registering(Copy::class) {
     it
       // Shorten FQCNs for same-package references generated by jsonschema2pojo
       .replace("io.opentelemetry.sdk.autoconfigure.declarativeconfig.model.", "")
-      // Remove @Nullable annotation so it can be deterministically added later
-      .replace("import javax.annotation.Nullable;\n", "")
       // Replace java 9+ @Generated annotation with java 8 version, add @Nullable annotation
-      .replace("import javax.annotation.processing.Generated;", "import javax.annotation.Nullable;\nimport javax.annotation.Generated;")
-      // Add @SuppressWarnings annotations for issues inherent in jsonschema2pojo-generated code:
-      //   "rawtypes" - raw types used in builders
-      //   "NullAway" - uninitialized @NonNull fields on Jackson-deserialized POJOs
-      //     TODO(jack-berg): investigate jsonschema2pojo config to avoid @Nonnull on fields / generate initializing constructors
-      //   "BoxedPrimitiveEquality" - == comparison of boxed primitives in generated equals()
-      //     TODO(jack-berg): investigate jsonschema2pojo config for alternative equals implementation that avoids boxed primitives comparison
-      .replace(
-        "@Generated(\"jsonschema2pojo\")",
-        "@Generated(\"jsonschema2pojo\")\n@SuppressWarnings({\"NullAway\", \"rawtypes\", \"BoxedPrimitiveEquality\"})"
-      )
-      // Add @Nullable annotations to all getters (except getAdditionalProperties which is non-null)
-      .replace("( *)public (.+) get(?!AdditionalProperties)([a-zA-Z]*)".toRegex(), "$1@Nullable\n$1public $2 get$3")
+      .replace("import javax.annotation.processing.Generated;", "import javax.annotation.Generated;")
   }
 }