Add databinding option to not auto apply DoNotHash (#539)

epoxy-annotations/src/main/java/com/airbnb/epoxy/EpoxyDataBindingLayouts.java

@@ -23,4 +23,15 @@
 public @interface EpoxyDataBindingLayouts {
   /** A list of databinding layout resources that should have EpoxyModel's generated for them. */
   @LayoutRes int[] value();
+
+  /**
+     * If true, any variable whose type does not implement equals and hashcode will have the
+   * {@link EpoxyAttribute.Option#DoNotHash} behavior applied to them automatically.
+   * <p>
+   * This is generally helpful for listeners - other variables should almost always implement
+   * equals and hashcode.
+   * <p>
+   * For details on the nuances of this, see https://github.com/airbnb/epoxy/wiki/DoNotHash
+   */
+  boolean enableDoNotHash() default true;
 }

epoxy-annotations/src/main/java/com/airbnb/epoxy/EpoxyDataBindingPattern.java

@@ -29,4 +29,15 @@
    * databinding layout, Epoxy will generate a HeaderBindingModel_ class for that layout.
    */
   String layoutPrefix();
+
+  /**
+   * If true, any variable whose type does not implement equals and hashcode will have the
+   * {@link EpoxyAttribute.Option#DoNotHash} behavior applied to them automatically.
+   * <p>
+   * This is generally helpful for listeners - other variables should almost always implement
+   * equals and hashcode.
+   * <p>
+   * For details on the nuances of this, see https://github.com/airbnb/epoxy/wiki/DoNotHash
+   */
+  boolean enableDoNotHash() default true;
 }

epoxy-processor/src/main/java/com/airbnb/epoxy/DataBindingAttributeInfo.kt

@@ -14,8 +14,8 @@ internal class DataBindingAttributeInfo(
         typeMirror = setterMethod.parameters[0].asType()
         modelName = modelInfo.generatedName.simpleName()
         packageName = modelInfo.generatedName.packageName()
-        useInHash = hashCodeValidator.implementsHashCodeAndEquals(typeMirror)
-        ignoreRequireHashCode = false
+        useInHash = !modelInfo.enableDoNotHash || hashCodeValidator.implementsHashCodeAndEquals(typeMirror)
+        ignoreRequireHashCode = true
         generateSetter = true
         generateGetter = true
         hasFinalModifier = false

epoxy-processor/src/main/java/com/airbnb/epoxy/DataBindingModelInfo.kt

@@ -13,7 +13,8 @@ internal class DataBindingModelInfo(
     private val elementUtils: Elements,
     val layoutResource: ResourceValue,
     val moduleName: String,
-    private val layoutPrefix: String = ""
+    private val layoutPrefix: String = "",
+    val enableDoNotHash: Boolean
 ) : GeneratedModelInfo() {
     private val dataBindingClassName: ClassName
 
@@ -46,8 +47,8 @@ internal class DataBindingModelInfo(
         // This databinding class won't exist until the second round of annotation processing since
         // it is generated in the first round.
         val dataBindingClassElement = this.dataBindingClassElement ?: return false
-
         val hashCodeValidator = HashCodeValidator(typeUtils, elementUtils)
+
         dataBindingClassElement.executableElements()
             .filter { Utils.isSetterMethod(it) }
             .map {
@@ -57,6 +58,7 @@ internal class DataBindingModelInfo(
             .let {
                 addAttributes(it)
             }
+
         return true
     }
 
@@ -66,7 +68,7 @@ internal class DataBindingModelInfo(
     ): ClassName {
         val modelName = layoutResource.resourceName!!.toUpperCamelCase().plus(BINDING_SUFFIX)
 
-        return ClassName.get(moduleName + ".databinding", modelName)
+        return ClassName.get("$moduleName.databinding", modelName)
     }
 
     private fun buildGeneratedModelName(): ClassName {
@@ -81,7 +83,7 @@ internal class DataBindingModelInfo(
 
     companion object {
 
-        val BINDING_SUFFIX = "Binding"
+        const val BINDING_SUFFIX = "Binding"
 
         val FIELD_NAME_BLACKLIST = listOf(
             // Starting with Android plugin 3.1.0 nested DataBinding classes have a

epoxy-processor/src/main/java/com/airbnb/epoxy/DataBindingProcessor.kt

@@ -1,20 +1,21 @@
 package com.airbnb.epoxy
 
-import com.airbnb.epoxy.Utils.*
-import com.squareup.javapoet.*
+import com.airbnb.epoxy.Utils.getClassParamFromAnnotation
+import com.squareup.javapoet.ClassName
 import java.util.*
-import javax.annotation.processing.*
-import javax.lang.model.element.*
-import javax.lang.model.util.*
+import javax.annotation.processing.RoundEnvironment
+import javax.lang.model.element.VariableElement
+import javax.lang.model.util.Elements
+import javax.lang.model.util.Types
 
 internal class DataBindingProcessor(
-        private val elements: Elements,
-        private val types: Types,
-        private val errorLogger: ErrorLogger,
-        private val configManager: ConfigManager,
-        private val resourceProcessor: ResourceProcessor,
-        private val dataBindingModuleLookup: DataBindingModuleLookup,
-        private val modelWriter: GeneratedModelWriter
+    private val elements: Elements,
+    private val types: Types,
+    private val errorLogger: ErrorLogger,
+    private val configManager: ConfigManager,
+    private val resourceProcessor: ResourceProcessor,
+    private val dataBindingModuleLookup: DataBindingModuleLookup,
+    private val modelWriter: GeneratedModelWriter
 ) {
     private val modelsToWrite = ArrayList<DataBindingModelInfo>()
 
@@ -23,40 +24,58 @@ internal class DataBindingProcessor(
         roundEnv.getElementsAnnotatedWith(EpoxyDataBindingLayouts::class.java).forEach {
 
             val layoutResources = resourceProcessor
-                    .getLayoutsInAnnotation(it, EpoxyDataBindingLayouts::class.java)
+                .getLayoutsInAnnotation(it, EpoxyDataBindingLayouts::class.java)
 
             // Get the module name after parsing resources so we can use the resource classes to figure
             // out the module name
             val moduleName = dataBindingModuleLookup.getModuleName(it)
 
+            val enableDoNotHash =
+                it.annotation<EpoxyDataBindingLayouts>()?.enableDoNotHash == true
             layoutResources.mapTo(modelsToWrite) {
-                DataBindingModelInfo(types, elements, it, moduleName)
+                DataBindingModelInfo(
+                    typeUtils = types,
+                    elementUtils = elements,
+                    layoutResource = it,
+                    moduleName = moduleName,
+                    enableDoNotHash = enableDoNotHash
+                )
             }
         }
 
-        roundEnv.getElementsAnnotatedWith(EpoxyDataBindingPattern::class.java).forEach {
-            val patternAnnotation = it.getAnnotation(EpoxyDataBindingPattern::class.java)
+        roundEnv.getElementsAnnotatedWith(EpoxyDataBindingPattern::class.java).forEach { element ->
+            val patternAnnotation = element.getAnnotation(EpoxyDataBindingPattern::class.java)
 
             val layoutPrefix = patternAnnotation.layoutPrefix
             val rClassName = getClassParamFromAnnotation<EpoxyDataBindingPattern>(
-                    it,
-                    EpoxyDataBindingPattern::class.java,
-                    "rClass",
-                    types)
-                    ?: return@forEach
+                element,
+                EpoxyDataBindingPattern::class.java,
+                "rClass",
+                types
+            )
+                ?: return@forEach
 
             val moduleName = rClassName.packageName()
             val layoutClassName = ClassName.get(moduleName, "R", "layout")
+            val enableDoNotHash =
+                element.annotation<EpoxyDataBindingLayouts>()?.enableDoNotHash == true
 
             Utils.getElementByName(layoutClassName, elements, types)
-                    .enclosedElements
-                    .filterIsInstance<VariableElement>()
-                    .map { it.simpleName.toString() }
-                    .filter { it.startsWith(layoutPrefix) }
-                    .map { ResourceValue(layoutClassName, it, 0 /* value doesn't matter */) }
-                    .mapTo(modelsToWrite) {
-                        DataBindingModelInfo(types, elements, it, moduleName, layoutPrefix)
-                    }
+                .enclosedElements
+                .filterIsInstance<VariableElement>()
+                .map { it.simpleName.toString() }
+                .filter { it.startsWith(layoutPrefix) }
+                .map { ResourceValue(layoutClassName, it, 0 /* value doesn't matter */) }
+                .mapTo(modelsToWrite) {
+                    DataBindingModelInfo(
+                        typeUtils = types,
+                        elementUtils = elements,
+                        layoutResource = it,
+                        moduleName = moduleName,
+                        layoutPrefix = layoutPrefix,
+                        enableDoNotHash = enableDoNotHash
+                    )
+                }
         }
 
         val modelsWritten = resolveDataBindingClassesAndWriteJava()
@@ -79,15 +98,15 @@ internal class DataBindingProcessor(
 
     private fun resolveDataBindingClassesAndWriteJava(): List<DataBindingModelInfo> {
         return modelsToWrite
-                .filter { it.parseDataBindingClass() }
-                .onEach {
-                    try {
-                        modelWriter.generateClassForModel(it)
-                    } catch (e: Exception) {
-                        errorLogger.logError(e, "Error generating model classes")
-                    }
-
-                    modelsToWrite.remove(it)
+            .filter { it.parseDataBindingClass() }
+            .onEach {
+                try {
+                    modelWriter.generateClassForModel(it)
+                } catch (e: Exception) {
+                    errorLogger.logError(e, "Error generating model classes")
                 }
+
+                modelsToWrite.remove(it)
+            }
     }
 }

epoxy-processor/src/main/java/com/airbnb/epoxy/KotlinUtils.kt

@@ -159,6 +159,8 @@ fun Element.iterateSuperClasses(
     }
 }
 
+inline fun <reified T : Annotation> Element.annotation(): T? = getAnnotation(T::class.java)
+
 /**
  * Returns a list of annotations specs representing annotations on the given type element.
  *

epoxy-processortest/src/main/res/layout/model_with_data_binding_without_donothash.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <data>
+
+        <variable
+            name="stringValue"
+            type="String" />
+
+        <variable
+            name="clickListener"
+            type="android.view.View.OnClickListener" />
+    </data>
+
+    <Button
+        android:id="@+id/button"
+        android:layout_width="match_parent"
+        android:layout_height="40dp"
+        android:onClick="@{clickListener}"
+        android:text="@{stringValue}" />
+
+</layout>

epoxy-processortest/src/test/java/com/airbnb/epoxy/DataBindingModelTest.java

@@ -28,6 +28,7 @@ public class DataBindingModelTest {
       + "  public static final class layout {\n"
       + "    public static final int res = 0x7f040008;\n"
       + "    public static final int model_with_data_binding=0x7f040009;\n"
+      + "    public static final int model_with_data_binding_without_donothash=0x7f0f002b;\n"
       + "  }\n"
       + "  public static final class integer {\n"
       + "    public static final int res = 0x7f040004;\n"
@@ -66,6 +67,7 @@ public class DataBindingModelTest {
               + "  public static final int valueObject = 20;\n"
               + "  public static final int valueList = 21;\n"
               + "  public static final int stringValue = 22;\n"
+              + "  public static final int clickListener = 23;\n"
               + "}");
 
   @Test
@@ -118,4 +120,27 @@ public void testFullyGeneratedModel() {
         .and()
         .generatesSources(generatedModel);
   }
+
+  @Test
+  public void testFullyGeneratedModelWithoutDoNotHash() {
+    JavaFileObject packageInfo = JavaFileObjects
+        .forSourceString("com.airbnb.epoxy.package-info",
+            "@EpoxyDataBindingLayouts(value = {R.layout"
+                + ".model_with_data_binding_without_donothash}, enableDoNotHash = false)\n"
+                + "package com.airbnb.epoxy;\n"
+        );
+
+    JavaFileObject binding = JavaFileObjects
+        .forResource("ModelWithDataBindingWithoutDonothashBinding.java");
+
+    JavaFileObject generatedModel =
+        JavaFileObjects.forResource("ModelWithDataBindingWithoutDonothashBindingModel_.java");
+
+    assert_().about(javaSources())
+        .that(asList(packageInfo, binding, BR_CLASS, R))
+        .processedWith(new EpoxyProcessor())
+        .compilesWithoutError()
+        .and()
+        .generatesSources(generatedModel);
+  }
 }