Guice module breaks when binding configs of config that has empty list fix #1337

Author: jknack

TODO

@@ -1,7 +1,7 @@
 * tests and coverage
 * server options from application.conf MUST override hardcoded settings
 * raw responses, sendXXX should not allow decorator
-
+* Add injection support for App instance. So we can annotated instance fields
 * make reset headers on error configurable
 
 * websockets

jooby/src/main/java/io/jooby/internal/ClassPathAssetSource.java

@@ -1,3 +1,8 @@
+/**
+ * Jooby https://jooby.io
+ * Apache License Version 2.0 https://jooby.io/LICENSE.txt
+ * Copyright 2014 Edgar Espina
+ */
 package io.jooby.internal;
 
 import io.jooby.Asset;

jooby/src/main/java/io/jooby/internal/FileAsset.java

@@ -1,3 +1,8 @@
+/**
+ * Jooby https://jooby.io
+ * Apache License Version 2.0 https://jooby.io/LICENSE.txt
+ * Copyright 2014 Edgar Espina
+ */
 package io.jooby.internal;
 
 import io.jooby.Asset;

jooby/src/main/java/io/jooby/internal/JarAsset.java

@@ -1,3 +1,8 @@
+/**
+ * Jooby https://jooby.io
+ * Apache License Version 2.0 https://jooby.io/LICENSE.txt
+ * Copyright 2014 Edgar Espina
+ */
 package io.jooby.internal;
 
 import io.jooby.Asset;

jooby/src/main/java/io/jooby/internal/URLAsset.java

@@ -1,3 +1,8 @@
+/**
+ * Jooby https://jooby.io
+ * Apache License Version 2.0 https://jooby.io/LICENSE.txt
+ * Copyright 2014 Edgar Espina
+ */
 package io.jooby.internal;
 
 import io.jooby.Asset;

modules/jooby-guice/pom.xml

@@ -38,6 +38,11 @@
       <scope>test</scope>
     </dependency>
 
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+    </dependency>
+
     <dependency>
       <groupId>org.jacoco</groupId>
       <artifactId>org.jacoco.agent</artifactId>

modules/jooby-guice/src/main/java/io/jooby/di/JoobyModule.java

@@ -64,7 +64,7 @@ private void configureResources(ServiceRegistry registry) {
     }
   }
 
-  private void configureEnv(Environment env) {
+  /*package*/ void configureEnv(Environment env) {
     Config config = env.getConfig();
     bind(Config.class).toInstance(config);
     bind(Environment.class).toInstance(env);
@@ -76,7 +76,9 @@ private void configureEnv(Environment env) {
       Object value = entry.getValue().unwrapped();
       if (value instanceof List) {
         List values = (List) value;
-        Type listType = Types.listOf(values.iterator().next().getClass());
+        Type listType = values.size() == 0
+            ? Types.listOf(String.class)
+            : Types.listOf(values.get(0).getClass());
         Key key = Key.get(listType, Names.named(name));
         bind(key).toInstance(values);
         value = values.stream().map(Object::toString).collect(Collectors.joining(","));

modules/jooby-guice/src/test/java/io/jooby/di/JoobyModuleTest.java

@@ -0,0 +1,75 @@
+package io.jooby.di;
+
+import com.google.inject.Binder;
+import com.google.inject.Key;
+import com.google.inject.TypeLiteral;
+import com.google.inject.binder.AnnotatedBindingBuilder;
+import com.google.inject.binder.AnnotatedConstantBindingBuilder;
+import com.google.inject.binder.ConstantBindingBuilder;
+import com.google.inject.binder.LinkedBindingBuilder;
+import com.google.inject.name.Names;
+import com.google.inject.util.Types;
+import com.typesafe.config.Config;
+import com.typesafe.config.ConfigFactory;
+import io.jooby.Environment;
+import io.jooby.Jooby;
+import io.jooby.ServiceRegistry;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class JoobyModuleTest {
+  @Test
+  @DisplayName("Guice should not break on empty list property. Empty list fallback to List<String>")
+  public void issue1337() {
+    List<String> emptyList = Collections.emptyList();
+    Map<String, Object> map = new HashMap<>();
+    map.put("some", emptyList);
+
+    Config config = ConfigFactory.parseMap(map);
+
+    Environment environment = mock(Environment.class);
+    when(environment.getConfig()).thenReturn(config);
+
+    ServiceRegistry registry = mock(ServiceRegistry.class);
+    when(registry.entrySet()).thenReturn(Collections.emptySet());
+
+    Jooby app = mock(Jooby.class);
+    when(app.getEnvironment()).thenReturn(environment);
+    when(app.getServices()).thenReturn(registry);
+
+    Binder binder = mock(Binder.class);
+
+    AnnotatedBindingBuilder<Environment> envbinding = mock(AnnotatedBindingBuilder.class);
+    when(binder.bind(Environment.class)).thenReturn(envbinding);
+
+    AnnotatedBindingBuilder<Config> confbinding = mock(AnnotatedBindingBuilder.class);
+    when(binder.bind(Config.class)).thenReturn(confbinding);
+
+    LinkedBindingBuilder emptyListBinding = mock(LinkedBindingBuilder.class);
+    emptyListBinding.toInstance(emptyList);
+    when(binder.bind(Key.get(Types.listOf(String.class), Names.named("some")))).thenReturn(emptyListBinding);
+
+    ConstantBindingBuilder constantBindingBuilder = mock(ConstantBindingBuilder.class);
+    constantBindingBuilder.to("");
+    AnnotatedConstantBindingBuilder constantBinding = mock(AnnotatedConstantBindingBuilder.class);
+    when(constantBinding.annotatedWith(Names.named("some"))).thenReturn(constantBindingBuilder);
+    when(binder.bindConstant()).thenReturn(constantBinding);
+
+    JoobyModule module = new JoobyModule(app);
+
+    module.configure(binder);
+
+    verify(envbinding).toInstance(environment);
+    verify(confbinding).toInstance(config);
+  }
+
+}