Pass -proc option to ECJ without explicit annotation processors

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

@@ -198,10 +198,10 @@ public CompilerResult performCompile(CompilerConfiguration config) throws Compil
                     args.add("--processor-module-path");
                     args.add(getPathString(processorModulePathEntries));
                 }
+            }
 
-                if (config.getProc() != null) {
-                    args.add("-proc:" + config.getProc());
-                }
+            if (config.getProc() != null) {
+                args.add("-proc:" + config.getProc());
             }
         }
 

plexus-compilers/plexus-compiler-eclipse/src/test/java/org/codehaus/plexus/compiler/eclipse/EclipseJavaCompilerTest.java

@@ -1,16 +1,27 @@
 package org.codehaus.plexus.compiler.eclipse;
 
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.List;
 import java.util.stream.Stream;
 
+import org.codehaus.plexus.compiler.CompilerConfiguration;
+import org.codehaus.plexus.compiler.CompilerResult;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
 import static java.util.Arrays.asList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class EclipseJavaCompilerTest {
+    @TempDir
+    Path tempDir;
+
     @ParameterizedTest
     @MethodSource("sources")
     void testReorderedSources(List<String> expected, List<String> inputSources) {
@@ -19,6 +30,55 @@ void testReorderedSources(List<String> expected, List<String> inputSources) {
         assertEquals(expected, resorted);
     }
 
+    @Test
+    void procNoneDisablesAnnotationProcessorDiscoveryWithoutExplicitProcessors() throws Exception {
+        Path sourceDirectory = tempDir.resolve("src");
+        Path sourceFile = sourceDirectory.resolve("demo/Example.java");
+        Files.createDirectories(sourceFile.getParent());
+        Files.writeString(sourceFile, "package demo;\n\npublic class Example {}\n");
+
+        Path outputDirectory = tempDir.resolve("classes");
+        Files.createDirectories(outputDirectory);
+        Path serviceFile = outputDirectory.resolve("META-INF/services/javax.annotation.processing.Processor");
+        Files.createDirectories(serviceFile.getParent());
+        Files.writeString(serviceFile, "demo.MissingProcessor\n");
+
+        CompilerConfiguration config = new CompilerConfiguration();
+        config.setSourceVersion("17");
+        config.addSourceLocation(sourceDirectory.toString());
+        config.setOutputLocation(outputDirectory.toString());
+        config.setProc("none");
+
+        CompilerResult result = new EclipseJavaCompiler().performCompile(config);
+
+        assertTrue(result.isSuccess(), () -> "Compilation failed: " + result.getCompilerMessages());
+        assertTrue(Files.exists(outputDirectory.resolve("demo/Example.class")), "Sources should still be compiled");
+    }
+
+    @Test
+    void procOnlyIsPassedToEcjWithoutExplicitProcessors() throws Exception {
+        Path sourceDirectory = tempDir.resolve("src");
+        Path sourceFile = sourceDirectory.resolve("demo/Only.java");
+        Files.createDirectories(sourceFile.getParent());
+        Files.writeString(sourceFile, "package demo;\n\npublic class Only {}\n");
+
+        Path outputDirectory = tempDir.resolve("only-classes");
+        Files.createDirectories(outputDirectory);
+
+        CompilerConfiguration config = new CompilerConfiguration();
+        config.setSourceVersion("17");
+        config.addSourceLocation(sourceDirectory.toString());
+        config.setOutputLocation(outputDirectory.toString());
+        config.setProc("only");
+
+        CompilerResult result = new EclipseJavaCompiler().performCompile(config);
+
+        assertTrue(result.isSuccess(), () -> "Compilation failed: " + result.getCompilerMessages());
+        assertFalse(
+                Files.exists(outputDirectory.resolve("demo/Only.class")),
+                "-proc:only should run annotation processing without compiling sources");
+    }
+
     static Stream<Arguments> sources() {
         List<String> expectedOrder = asList("module-info.java", "plexus/A.java", "plexus/B.java", "eclipse/A.java");