Fix ECJ not using annotation processor when defined via processorpath

Works around https://bugs.eclipse.org/bugs/show_bug.cgi?id=573833 by
adding -classpath to the command line before -processorpath is added.

Fixes #349

plexus-compiler-its/src/main/it/eclipse-compiler-mapstruct/pom.xml

@@ -24,18 +24,16 @@
   <modelVersion>4.0.0</modelVersion>
 
   <groupId>org.codehaus.plexus.compiler.it</groupId>
-  <artifactId>simple-javac</artifactId>
+  <artifactId>eclipse-compiler-mapstruct</artifactId>
   <version>1.0-SNAPSHOT</version>
 
-  <name>Test for default configuration</name>
-
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     <maven.compiler.source>1.8</maven.compiler.source>
     <maven.compiler.target>1.8</maven.compiler.target>
     <plexus.compiler.version>@pom.version@</plexus.compiler.version>
-    <org.mapstruct.version>1.5.2.Final</org.mapstruct.version>
+    <org.mapstruct.version>1.5.5.Final</org.mapstruct.version>
   </properties>
 
   <dependencies>

plexus-compiler-its/src/main/it/eclipse-compiler-procpath/invoker.properties

@@ -0,0 +1,21 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+# 
+#   http://www.apache.org/licenses/LICENSE-2.0
+# 
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+invoker.maven.version = 3.9.6+
+
+invoker.goals = clean compile
+invoker.buildResult = success

plexus-compiler-its/src/main/it/eclipse-compiler-procpath/pom.xml

@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Licensed to the Apache Software Foundation (ASF) under one
+  ~ or more contributor license agreements.  See the NOTICE file
+  ~ distributed with this work for additional information
+  ~ regarding copyright ownership.  The ASF licenses this file
+  ~ to you under the Apache License, Version 2.0 (the
+  ~ "License"); you may not use this file except in compliance
+  ~ with the License.  You may obtain a copy of the License at
+  ~
+  ~   http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing,
+  ~ software distributed under the License is distributed on an
+  ~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+  ~ KIND, either express or implied.  See the License for the
+  ~ specific language governing permissions and limitations
+  ~ under the License.
+  -->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.codehaus.plexus.compiler.it</groupId>
+  <artifactId>eclipse-compiler-procpath</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+    <plexus.compiler.version>@pom.version@</plexus.compiler.version>
+    <org.mapstruct.version>1.5.5.Final</org.mapstruct.version>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.mapstruct</groupId>
+      <artifactId>mapstruct</artifactId>
+      <version>${org.mapstruct.version}</version>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>@maven.compiler.version@</version>
+        <configuration>
+          <compilerId>eclipse</compilerId>
+          <annotationProcessorPaths>
+            <path>
+              <groupId>org.mapstruct</groupId>
+              <artifactId>mapstruct-processor</artifactId>
+              <version>${org.mapstruct.version}</version>
+            </path>
+          </annotationProcessorPaths>
+        </configuration>
+        <dependencies>
+          <dependency>
+            <groupId>org.codehaus.plexus</groupId>
+            <artifactId>plexus-compiler-api</artifactId>
+            <version>${plexus.compiler.version}</version>
+          </dependency>
+          <dependency>
+            <groupId>org.codehaus.plexus</groupId>
+            <artifactId>plexus-compiler-eclipse</artifactId>
+            <version>${plexus.compiler.version}</version>
+          </dependency>
+        </dependencies>
+      </plugin>
+    </plugins>
+  </build>
+
+</project>

plexus-compiler-its/src/main/it/eclipse-compiler-procpath/src/main/java/Car.java

@@ -0,0 +1,24 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+public class Car
+{
+    public String make;
+    public int numberOfSeats;
+}

plexus-compiler-its/src/main/it/eclipse-compiler-procpath/src/main/java/CarDto.java

@@ -0,0 +1,24 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+public class CarDto
+{
+    public String make;
+    public int seatCount;
+}

plexus-compiler-its/src/main/it/eclipse-compiler-procpath/src/main/java/CarMapper.java

@@ -0,0 +1,32 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.factory.Mappers;
+
+@Mapper
+public interface CarMapper
+{
+
+    CarMapper INSTANCE = Mappers.getMapper( CarMapper.class );
+
+    @Mapping( source = "numberOfSeats", target = "seatCount" )
+    CarDto carToCarDto( Car car );
+}

plexus-compiler-its/src/main/it/eclipse-compiler-procpath/verify.groovy

@@ -0,0 +1,21 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+def mapperImplClass = new File( basedir, "target/classes/CarMapperImpl.class" )
+assert mapperImplClass.exists()
+

plexus-compilers/plexus-compiler-eclipse/src/main/java/org/codehaus/plexus/compiler/eclipse/EclipseJavaCompiler.java

@@ -147,7 +147,21 @@ public CompilerResult performCompile(CompilerConfiguration config) throws Compil
         args.add("-d");
         args.add(config.getOutputLocation());
 
+        // -- classpath
+        // must be done before annotation processors: https://bugs.eclipse.org/bugs/show_bug.cgi?id=573833
+        List<String> classpathEntries = new ArrayList<>(config.getClasspathEntries());
+        classpathEntries.add(config.getOutputLocation());
+        args.add("-classpath");
+        args.add(getPathString(classpathEntries));
+
+        List<String> modulepathEntries = config.getModulepathEntries();
+        if (modulepathEntries != null && !modulepathEntries.isEmpty()) {
+            args.add("--module-path");
+            args.add(getPathString(modulepathEntries));
+        }
+
         // Annotation processors defined?
+        // must be done after classpath: https://bugs.eclipse.org/bugs/show_bug.cgi?id=573833
         if (!isPreJava1_6(config)) {
             File generatedSourcesDir = config.getGeneratedSourcesDirectory();
             if (generatedSourcesDir != null) {
@@ -198,18 +212,6 @@ public CompilerResult performCompile(CompilerConfiguration config) throws Compil
             }
         }
 
-        // -- classpath
-        List<String> classpathEntries = new ArrayList<>(config.getClasspathEntries());
-        classpathEntries.add(config.getOutputLocation());
-        args.add("-classpath");
-        args.add(getPathString(classpathEntries));
-
-        List<String> modulepathEntries = config.getModulepathEntries();
-        if (modulepathEntries != null && !modulepathEntries.isEmpty()) {
-            args.add("--module-path");
-            args.add(getPathString(modulepathEntries));
-        }
-
         // Collect sources
         List<String> allSources = Arrays.asList(getSourceFiles(config));
         List<CompilerMessage> messageList = new ArrayList<>();