Repository: square/anvil
Issue: Connot find symbol exception for properties provided in a dagger module in a seperate gradle module

In gradle module A:
``` kotlin
class Foo
@Module class MyModule {
    @get:Provides val foo = Foo()
}
```
In gradle module B which depends on A:
``` kotlin
@Component(modules = [MyModule::class]) interface MyComponent {
    fun foo(): Foo
}
```
```
build/generated/source/kapt/debug/com/package/package/DaggerMyComponent.java:5: error: cannot find symbol
import com.package.package.MyModule_GetFooFactory;
                          ^

Changed files:
compiler/src/main/java/com/squareup/anvil/compiler/codegen/PsiUtils.kt
compiler/src/test/java/com/squareup/anvil/compiler/dagger/ProvidesMethodFactoryGeneratorTest.kt
compiler/src/main/java/com/squareup/anvil/compiler/codegen/dagger/ProvidesMethodFactoryGenerator.kt

diff --git a/compiler/src/main/java/com/squareup/anvil/compiler/codegen/PsiUtils.kt b/compiler/src/main/java/com/squareup/anvil/compiler/codegen/PsiUtils.kt
index 84d4ffa..a4ddda9 100644
--- a/compiler/src/main/java/com/squareup/anvil/compiler/codegen/PsiUtils.kt
+++ b/compiler/src/main/java/com/squareup/anvil/compiler/codegen/PsiUtils.kt
@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.psi.KtNameReferenceExpression
 import org.jetbrains.kotlin.psi.KtNamedDeclaration
 import org.jetbrains.kotlin.psi.KtNamedFunction
 import org.jetbrains.kotlin.psi.KtNullableType
+import org.jetbrains.kotlin.psi.KtProperty
 import org.jetbrains.kotlin.psi.KtTypeArgumentList
 import org.jetbrains.kotlin.psi.KtTypeReference
 import org.jetbrains.kotlin.psi.KtUserType
@@ -355,15 +356,18 @@ internal fun ModuleDescriptor.findClassOrTypeAlias(
 
 internal fun KtClassOrObject.functions(
   includeCompanionObjects: Boolean
-): List<KtNamedFunction> {
+): List<KtNamedFunction> = classBodies(includeCompanionObjects).flatMap { it.functions }
+
+internal fun KtClassOrObject.properties(
+  includeCompanionObjects: Boolean
+): List<KtProperty> = classBodies(includeCompanionObjects).flatMap { it.properties }
+
+private fun KtClassOrObject.classBodies(includeCompanionObjects: Boolean): List<KtClassBody> {
   val elements = children.toMutableList()
   if (includeCompanionObjects) {
     elements += companionObjects.flatMap { it.children.toList() }
   }
-
-  return elements
-      .filterIsInstance<KtClassBody>()
-      .flatMap { it.functions }
+  return elements.filterIsInstance<KtClassBody>()
 }
 
 fun KtTypeReference.isNullable(): Boolean = typeElement is KtNullableType
diff --git a/compiler/src/main/java/com/squareup/anvil/compiler/codegen/dagger/ProvidesMethodFactoryGenerator.kt b/compiler/src/main/java/com/squareup/anvil/compiler/codegen/dagger/ProvidesMethodFactoryGenerator.kt
index b69bd39..5a91c36 100644
--- a/compiler/src/main/java/com/squareup/anvil/compiler/codegen/dagger/ProvidesMethodFactoryGenerator.kt
+++ b/compiler/src/main/java/com/squareup/anvil/compiler/codegen/dagger/ProvidesMethodFactoryGenerator.kt
@@ -7,10 +7,12 @@ import com.squareup.anvil.compiler.codegen.addGeneratedByComment
 import com.squareup.anvil.compiler.codegen.asArgumentList
 import com.squareup.anvil.compiler.codegen.asClassName
 import com.squareup.anvil.compiler.codegen.classesAndInnerClasses
+import com.squareup.anvil.compiler.codegen.findAnnotation
 import com.squareup.anvil.compiler.codegen.functions
 import com.squareup.anvil.compiler.codegen.hasAnnotation
 import com.squareup.anvil.compiler.codegen.isNullable
 import com.squareup.anvil.compiler.codegen.mapToParameter
+import com.squareup.anvil.compiler.codegen.properties
 import com.squareup.anvil.compiler.codegen.requireFqName
 import com.squareup.anvil.compiler.codegen.requireTypeName
 import com.squareup.anvil.compiler.codegen.requireTypeReference
@@ -32,10 +34,11 @@ import com.squareup.kotlinpoet.jvm.jvmStatic
 import dagger.internal.Factory
 import dagger.internal.Preconditions
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
+import org.jetbrains.kotlin.psi.KtCallableDeclaration
 import org.jetbrains.kotlin.psi.KtClassOrObject
 import org.jetbrains.kotlin.psi.KtFile
-import org.jetbrains.kotlin.psi.KtNamedFunction
 import org.jetbrains.kotlin.psi.KtObjectDeclaration
+import org.jetbrains.kotlin.psi.KtProperty
 import org.jetbrains.kotlin.psi.psiUtil.parents
 import java.io.File
 import java.util.Locale.US
@@ -73,6 +76,17 @@ internal class ProvidesMethodFactoryGenerator : PrivateCodeGenerator() {
               .forEach { function ->
                 generateFactoryClass(codeGenDir, module, clazz, function)
               }
+
+          clazz
+              .properties(includeCompanionObjects = true)
+              .asSequence()
+              .filter { property ->
+                // Must be '@get:Provides'.
+                property.findAnnotation(daggerProvidesFqName)?.useSiteTarget?.text == "get"
+              }
+              .forEach { property ->
+                generateFactoryClass(codeGenDir, module, clazz, property)
+              }
         }
   }
 
@@ -81,30 +95,48 @@ internal class ProvidesMethodFactoryGenerator : PrivateCodeGenerator() {
     codeGenDir: File,
     module: ModuleDescriptor,
     clazz: KtClassOrObject,
-    function: KtNamedFunction
+    declaration: KtCallableDeclaration
   ): GeneratedFile {
-    val isCompanionObject = function.parents
+    val isCompanionObject = declaration.parents
         .filterIsInstance<KtObjectDeclaration>()
         .firstOrNull()
         ?.isCompanion()
         ?: false
     val isObject = isCompanionObject || clazz is KtObjectDeclaration
 
+    val isProperty = declaration is KtProperty
+
     val packageName = clazz.containingKtFile.packageFqName.asString()
-    val className = "${clazz.generateClassName()}_" +
-        (if (isCompanionObject) "Companion_" else "") +
-        "${function.requireFqName().shortName().asString().capitalize(US)}Factory"
-    val functionName = function.nameAsSafeName.asString()
+    val className = buildString {
+      append(clazz.generateClassName())
+      append('_')
+      if (isCompanionObject) {
+        append("Companion_")
+      }
+      if (isProperty) {
+        append("Get")
+      }
+      append(declaration.requireFqName().shortName().asString().capitalize(US))
+      append("Factory")
+    }
 
-    val parameters = function.valueParameters.mapToParameter(module)
+    val callableName = declaration.nameAsSafeName.asString()
 
-    val returnType = function.requireTypeReference().requireTypeName(module)
-        .withJvmSuppressWildcardsIfNeeded(function)
-    val returnTypeIsNullable = function.typeReference?.isNullable() ?: false
+    val parameters = declaration.valueParameters.mapToParameter(module)
+
+    val returnType = declaration.requireTypeReference().requireTypeName(module)
+        .withJvmSuppressWildcardsIfNeeded(declaration)
+    val returnTypeIsNullable = declaration.typeReference?.isNullable() ?: false
 
     val factoryClass = ClassName(packageName, className)
     val moduleClass = clazz.asClassName()
 
+    val byteCodeFunctionName = if (isProperty) {
+      "get" + callableName.capitalize(US)
+    } else {
+      callableName
+    }
+
     val content = FileSpec.builder(packageName, className)
         .apply {
           val canGenerateAnObject = isObject && parameters.isEmpty()
@@ -158,7 +190,7 @@ internal class ProvidesMethodFactoryGenerator : PrivateCodeGenerator() {
                             asProvider = true,
                             includeModule = !isObject
                         )
-                        addStatement("return $functionName($argumentList)")
+                        addStatement("return $byteCodeFunctionName($argumentList)")
                       }
                       .build()
               )
@@ -191,7 +223,7 @@ internal class ProvidesMethodFactoryGenerator : PrivateCodeGenerator() {
                             .build()
                     )
                     .addFunction(
-                        FunSpec.builder(functionName)
+                        FunSpec.builder(byteCodeFunctionName)
                             .jvmStatic()
                             .apply {
                               if (!isObject) {
@@ -204,30 +236,35 @@ internal class ProvidesMethodFactoryGenerator : PrivateCodeGenerator() {
                                     type = parameter.originalTypeName
                                 )
                               }
-                              val argumentsWithoutModule = parameters.joinToString { it.name }
+
+                              val argumentsWithoutModule = if (isProperty) {
+                                ""
+                              } else {
+                                "(${parameters.joinToString { it.name }})"
+                              }
 
                               when {
                                 isObject && returnTypeIsNullable ->
                                   addStatement(
-                                      "return %T.$functionName($argumentsWithoutModule)",
+                                      "return %T.$callableName$argumentsWithoutModule",
                                       moduleClass
                                   )
                                 isObject && !returnTypeIsNullable ->
                                   addStatement(
-                                      "return %T.checkNotNull(%T.$functionName" +
-                                          "($argumentsWithoutModule), %S)",
+                                      "return %T.checkNotNull(%T.$callableName" +
+                                          "$argumentsWithoutModule, %S)",
                                       Preconditions::class,
                                       moduleClass,
                                       "Cannot return null from a non-@Nullable @Provides method"
                                   )
                                 !isObject && returnTypeIsNullable ->
                                   addStatement(
-                                      "return module.$functionName($argumentsWithoutModule)"
+                                      "return module.$callableName$argumentsWithoutModule"
                                   )
                                 !isObject && !returnTypeIsNullable ->
                                   addStatement(
-                                      "return %T.checkNotNull(module.$functionName" +
-                                          "($argumentsWithoutModule), %S)",
+                                      "return %T.checkNotNull(module.$callableName" +
+                                          "$argumentsWithoutModule, %S)",
                                       Preconditions::class,
                                       "Cannot return null from a non-@Nullable @Provides method"
                                   )
diff --git a/compiler/src/test/java/com/squareup/anvil/compiler/dagger/ProvidesMethodFactoryGeneratorTest.kt b/compiler/src/test/java/com/squareup/anvil/compiler/dagger/ProvidesMethodFactoryGeneratorTest.kt
index 6dd4d6d..bd205f4 100644
--- a/compiler/src/test/java/com/squareup/anvil/compiler/dagger/ProvidesMethodFactoryGeneratorTest.kt
+++ b/compiler/src/test/java/com/squareup/anvil/compiler/dagger/ProvidesMethodFactoryGeneratorTest.kt
@@ -2440,6 +2440,358 @@ public final class DaggerComponentInterface implements ComponentInterface {
     }
   }
 
+  @Test fun `a factory class is generated for provided properties`() {
+    /*
+package com.squareup.test;
+
+import dagger.internal.Factory;
+import dagger.internal.Preconditions;
+import javax.annotation.processing.Generated;
+
+@Generated(
+    value = "dagger.internal.codegen.ComponentProcessor",
+    comments = "https://dagger.dev"
+)
+@SuppressWarnings({
+    "unchecked",
+    "rawtypes"
+})
+public final class DaggerModule1_GetStringFactory implements Factory<String> {
+  private final DaggerModule1 module;
+
+  public DaggerModule1_GetStringFactory(DaggerModule1 module) {
+    this.module = module;
+  }
+
+  @Override
+  public String get() {
+    return getString(module);
+  }
+
+  public static DaggerModule1_GetStringFactory create(DaggerModule1 module) {
+    return new DaggerModule1_GetStringFactory(module);
+  }
+
+  public static String getString(DaggerModule1 instance) {
+    return Preconditions.checkNotNull(instance.getString(), "Cannot return null from a non-@Nullable @Provides method");
+  }
+}
+     */
+    compile(
+        """
+        package com.squareup.test
+        
+        import dagger.Module
+        import dagger.Provides
+        
+        @Module
+        class DaggerModule1 {
+          @get:Provides val string: String = "abc"
+        }
+        """
+    ) {
+      val factoryClass = daggerModule1.moduleFactoryClass("getString")
+
+      val constructor = factoryClass.declaredConstructors.single()
+      assertThat(constructor.parameterTypes.toList()).containsExactly(daggerModule1)
+
+      val staticMethods = factoryClass.declaredMethods.filter { it.isStatic }
+
+      val module = daggerModule1.newInstance()
+
+      val factoryInstance = staticMethods.single { it.name == "create" }
+          .invoke(null, module)
+      assertThat(factoryInstance::class.java).isEqualTo(factoryClass)
+
+      val providedString = staticMethods.single { it.name == "getString" }
+          .invoke(null, module) as String
+
+      assertThat(providedString).isEqualTo("abc")
+      assertThat((factoryInstance as Factory<String>).get()).isEqualTo("abc")
+    }
+  }
+
+  @Test fun `a factory class is generated for provided properties in an object module`() {
+    /*
+package com.squareup.test;
+
+import dagger.internal.Factory;
+import dagger.internal.Preconditions;
+import javax.annotation.processing.Generated;
+
+@Generated(
+    value = "dagger.internal.codegen.ComponentProcessor",
+    comments = "https://dagger.dev"
+)
+@SuppressWarnings({
+    "unchecked",
+    "rawtypes"
+})
+public final class DaggerModule1_GetStringFactory implements Factory<String> {
+  @Override
+  public String get() {
+    return getString();
+  }
+
+  public static DaggerModule1_GetStringFactory create() {
+    return InstanceHolder.INSTANCE;
+  }
+
+  public static String getString() {
+    return Preconditions.checkNotNull(DaggerModule1.INSTANCE.getString(), "Cannot return null from a non-@Nullable @Provides method");
+  }
+
+  private static final class InstanceHolder {
+    private static final DaggerModule1_GetStringFactory INSTANCE = new DaggerModule1_GetStringFactory();
+  }
+}
+     */
+    compile(
+        """
+        package com.squareup.test
+        
+        import dagger.Module
+        import dagger.Provides
+        
+        @Module
+        object DaggerModule1 {
+          @get:Provides val string: String = "abc"
+        }
+        """
+    ) {
+      val factoryClass = daggerModule1.moduleFactoryClass("getString")
+
+      val constructor = factoryClass.declaredConstructors.single()
+      assertThat(constructor.parameterTypes.toList()).isEmpty()
+
+      val staticMethods = factoryClass.declaredMethods.filter { it.isStatic }
+
+      val factoryInstance = staticMethods.single { it.name == "create" }
+          .invoke(null)
+      assertThat(factoryInstance::class.java).isEqualTo(factoryClass)
+
+      val providedString = staticMethods.single { it.name == "getString" }
+          .invoke(null) as String
+
+      assertThat(providedString).isEqualTo("abc")
+      assertThat((factoryInstance as Factory<String>).get()).isEqualTo("abc")
+    }
+  }
+
+  @Test fun `a factory class is generated for provided properties in a companion object module`() {
+    /*
+package com.squareup.test;
+
+import dagger.internal.Factory;
+import dagger.internal.Preconditions;
+import javax.annotation.processing.Generated;
+
+@Generated(
+    value = "dagger.internal.codegen.ComponentProcessor",
+    comments = "https://dagger.dev"
+)
+@SuppressWarnings({
+    "unchecked",
+    "rawtypes"
+})
+public final class DaggerModule1_GetStringFactory implements Factory<String> {
+  @Override
+  public String get() {
+    return getString();
+  }
+
+  public static DaggerModule1_GetStringFactory create() {
+    return InstanceHolder.INSTANCE;
+  }
+
+  public static String getString() {
+    return Preconditions.checkNotNull(DaggerModule1.INSTANCE.getString(), "Cannot return null from a non-@Nullable @Provides method");
+  }
+
+  private static final class InstanceHolder {
+    private static final DaggerModule1_GetStringFactory INSTANCE = new DaggerModule1_GetStringFactory();
+  }
+}
+     */
+    compile(
+        """
+        package com.squareup.test
+        
+        import dagger.Binds
+        import dagger.Module
+        import dagger.Provides
+        
+        @Module
+        abstract class DaggerModule1 {
+          @Binds abstract fun bindString(string: String): CharSequence
+          
+          companion object {
+            @get:Provides val string: String = "abc"
+          }
+        }
+        """
+    ) {
+      val factoryClass = daggerModule1.moduleFactoryClass("getString", companion = true)
+
+      val constructor = factoryClass.declaredConstructors.single()
+      assertThat(constructor.parameterTypes.toList()).isEmpty()
+
+      val staticMethods = factoryClass.declaredMethods.filter { it.isStatic }
+
+      val factoryInstance = staticMethods.single { it.name == "create" }
+          .invoke(null)
+      assertThat(factoryInstance::class.java).isEqualTo(factoryClass)
+
+      val providedString = staticMethods.single { it.name == "getString" }
+          .invoke(null) as String
+
+      assertThat(providedString).isEqualTo("abc")
+      assertThat((factoryInstance as Factory<String>).get()).isEqualTo("abc")
+    }
+  }
+
+  @Test fun `a factory class is generated for provided nullable properties`() {
+    /*
+package com.squareup.test;
+
+import dagger.internal.Factory;
+import javax.annotation.processing.Generated;
+import org.jetbrains.annotations.Nullable;
+
+@Generated(
+    value = "dagger.internal.codegen.ComponentProcessor",
+    comments = "https://dagger.dev"
+)
+@SuppressWarnings({
+    "unchecked",
+    "rawtypes"
+})
+public final class DaggerModule1_GetStringFactory implements Factory<String> {
+  private final DaggerModule1 module;
+
+  public DaggerModule1_GetStringFactory(DaggerModule1 module) {
+    this.module = module;
+  }
+
+  @Override
+  @Nullable
+  public String get() {
+    return getString(module);
+  }
+
+  public static DaggerModule1_GetStringFactory create(DaggerModule1 module) {
+    return new DaggerModule1_GetStringFactory(module);
+  }
+
+  @Nullable
+  public static String getString(DaggerModule1 instance) {
+    return instance.getString();
+  }
+}
+     */
+    compile(
+        """
+        package com.squareup.test
+        
+        import dagger.Module
+        import dagger.Provides
+        
+        @Module
+        class DaggerModule1 {
+          @get:Provides val string: String? = null
+        }
+        """
+    ) {
+      val factoryClass = daggerModule1.moduleFactoryClass("getString")
+
+      val constructor = factoryClass.declaredConstructors.single()
+      assertThat(constructor.parameterTypes.toList()).containsExactly(daggerModule1)
+
+      val staticMethods = factoryClass.declaredMethods.filter { it.isStatic }
+
+      val module = daggerModule1.newInstance()
+
+      val factoryInstance = staticMethods.single { it.name == "create" }
+          .invoke(null, module)
+      assertThat(factoryInstance::class.java).isEqualTo(factoryClass)
+
+      val providedString = staticMethods.single { it.name == "getString" }
+          .invoke(null, module) as String?
+
+      assertThat(providedString).isNull()
+      assertThat((factoryInstance as Factory<String?>).get()).isNull()
+    }
+  }
+
+  @Test fun `a factory class is generated for provided nullable properties in an object module`() {
+    /*
+package com.squareup.test;
+
+import dagger.internal.Factory;
+import javax.annotation.processing.Generated;
+import org.jetbrains.annotations.Nullable;
+
+@Generated(
+    value = "dagger.internal.codegen.ComponentProcessor",
+    comments = "https://dagger.dev"
+)
+@SuppressWarnings({
+    "unchecked",
+    "rawtypes"
+})
+public final class DaggerModule1_GetStringFactory implements Factory<String> {
+  @Override
+  @Nullable
+  public String get() {
+    return getString();
+  }
+
+  public static DaggerModule1_GetStringFactory create() {
+    return InstanceHolder.INSTANCE;
+  }
+
+  @Nullable
+  public static String getString() {
+    return DaggerModule1.INSTANCE.getString();
+  }
+
+  private static final class InstanceHolder {
+    private static final DaggerModule1_GetStringFactory INSTANCE = new DaggerModule1_GetStringFactory();
+  }
+}
+     */
+    compile(
+        """
+        package com.squareup.test
+        
+        import dagger.Module
+        import dagger.Provides
+        
+        @Module
+        object DaggerModule1 {
+          @get:Provides val string: String? = null
+        }
+        """
+    ) {
+      val factoryClass = daggerModule1.moduleFactoryClass("getString")
+
+      val constructor = factoryClass.declaredConstructors.single()
+      assertThat(constructor.parameterTypes.toList()).isEmpty()
+
+      val staticMethods = factoryClass.declaredMethods.filter { it.isStatic }
+
+      val factoryInstance = staticMethods.single { it.name == "create" }
+          .invoke(null)
+      assertThat(factoryInstance::class.java).isEqualTo(factoryClass)
+
+      val providedString = staticMethods.single { it.name == "getString" }
+          .invoke(null) as String?
+
+      assertThat(providedString).isNull()
+      assertThat((factoryInstance as Factory<String?>).get()).isNull()
+    }
+  }
+
   private fun compile(
     vararg sources: String,
     block: Result.() -> Unit = { }