Update plugin-annotations to 1.13

* Add more checks to ensure plugin's are using @Plugin correctly.
* Add no-args constructor check.
* Break up some checks to get better error messages.
* Update error messages to be more informative.
* Update Bukkit version to 1.13
* Bump version

2 files changed, 33 insertions, 9 deletions

diff --git a/pom.xml b/pom.xml
index 47e0c68..bc130ae 100644
--- a/pom.xml
+++ b/pom.xml
@@ -10,7 +10,7 @@
 
     <groupId>org.spigotmc</groupId>
     <artifactId>plugin-annotations</artifactId>
-    <version>1.2.0-SNAPSHOT</version>
+    <version>1.2.1-SNAPSHOT</version>
     <packaging>jar</packaging>
 
     <name>Plugin Annotations</name>
@@ -54,7 +54,7 @@
         <dependency>
             <groupId>org.bukkit</groupId>
             <artifactId>bukkit</artifactId>
-            <version>1.12.2-R0.1-SNAPSHOT</version>
+            <version>1.13-R0.1-SNAPSHOT</version>
             <scope>compile</scope>
         </dependency>
         <!-- we don't currently have tests
diff --git a/src/main/java/org/bukkit/plugin/java/annotation/PluginAnnotationProcessor.java b/src/main/java/org/bukkit/plugin/java/annotation/PluginAnnotationProcessor.java
index 2f0f8d7..089e709 100644
--- a/src/main/java/org/bukkit/plugin/java/annotation/PluginAnnotationProcessor.java
+++ b/src/main/java/org/bukkit/plugin/java/annotation/PluginAnnotationProcessor.java
@@ -30,10 +30,12 @@ import javax.annotation.processing.SupportedAnnotationTypes;
 import javax.annotation.processing.SupportedSourceVersion;
 import javax.lang.model.SourceVersion;
 import javax.lang.model.element.Element;
+import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.Modifier;
 import javax.lang.model.element.PackageElement;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.type.TypeMirror;
+import javax.lang.model.util.ElementFilter;
 import javax.tools.Diagnostic;
 import javax.tools.FileObject;
 import javax.tools.StandardLocation;
@@ -67,7 +69,7 @@ public class PluginAnnotationProcessor extends AbstractProcessor {
             return false;
         }
 
-        if ( elements.isEmpty() ) {
+        if ( elements.isEmpty() ) { // don't raise error because we don't know which run this is
             return false;
         }
         if ( hasMainBeenFound ) {
@@ -81,19 +83,32 @@ public class PluginAnnotationProcessor extends AbstractProcessor {
         if ( mainPluginElement instanceof TypeElement ) {
             mainPluginType = ( TypeElement ) mainPluginElement;
         } else {
-            raiseError( "Element annotated with @Plugin is not a type!", mainPluginElement );
+            raiseError( "Main plugin class is not a class", mainPluginElement );
             return false;
         }
 
-        if ( !( mainPluginType.getEnclosingElement() instanceof PackageElement ) && !mainPluginType.getModifiers().contains( Modifier.STATIC ) ) {
-            raiseError( "Element annotated with @Plugin is not top-level or static nested!", mainPluginType );
+        if ( !( mainPluginType.getEnclosingElement() instanceof PackageElement ) ) {
+            raiseError( "Main plugin class is not a top-level class", mainPluginType );
+            return false;
+        }
+
+        if ( mainPluginType.getModifiers().contains( Modifier.STATIC ) ) {
+            raiseError( "Main plugin class cannot be static nested", mainPluginType );
             return false;
         }
 
         if ( !processingEnv.getTypeUtils().isSubtype( mainPluginType.asType(), fromClass( JavaPlugin.class ) ) ) {
-            raiseError( "Class annotated with @Plugin is not an subclass of JavaPlugin!", mainPluginType );
+            raiseError( "Main plugin class is not an subclass of JavaPlugin!", mainPluginType );
+        }
+
+        if ( mainPluginType.getModifiers().contains( Modifier.ABSTRACT ) ) {
+            raiseError( "Main plugin class cannot be abstract", mainPluginType );
+            return false;
         }
 
+        // check for no-args constructor
+        checkForNoArgsConstructor( mainPluginType );
+
         Map<String, Object> yml = Maps.newLinkedHashMap(); // linked so we can maintain the same output into file for sanity
 
         // populate mainName
@@ -227,11 +242,20 @@ public class PluginAnnotationProcessor extends AbstractProcessor {
         } catch ( IOException e ) {
             throw new RuntimeException( e );
         }
-
-        processingEnv.getMessager().printMessage( Diagnostic.Kind.WARNING, "NOTE: You are using org.bukkit.plugin.java.annotation, an experimental API!" );
         return true;
     }
 
+    private void checkForNoArgsConstructor(TypeElement mainPluginType) {
+        ExecutableElement construct = null;
+        for ( ExecutableElement constructor : ElementFilter.constructorsIn( mainPluginType.getEnclosedElements() ) ) {
+            if ( constructor.getParameters().isEmpty() ) {
+                return;
+            }
+            construct = constructor;
+        }
+        raiseError( "Main plugin class must have a no argument constructor.", construct );
+    }
+
     private void raiseError(String message) {
         this.processingEnv.getMessager().printMessage( Diagnostic.Kind.ERROR, message );
     }