Add support for annotation processors with TestCompiler

Closes spring-projectsgh-28582

Author: scottfrederick

spring-core-test/src/main/java/org/springframework/aot/test/generator/compile/TestCompiler.java

@@ -18,10 +18,13 @@
 
 import java.io.PrintStream;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.function.Consumer;
 
+import javax.annotation.processing.Processor;
 import javax.tools.Diagnostic;
 import javax.tools.DiagnosticListener;
 import javax.tools.JavaCompiler;
@@ -43,6 +46,7 @@
  * Utility that can be used to dynamically compile and test Java source code.
  *
  * @author Phillip Webb
+ * @author Scott Frederick
  * @since 6.0
  * @see #forSystem()
  */
@@ -57,13 +61,18 @@ public final class TestCompiler {
 
 	private final ResourceFiles resourceFiles;
 
+	private final List<Processor> processors;
+
 
 	private TestCompiler(@Nullable ClassLoader classLoader, JavaCompiler compiler,
-			SourceFiles sourceFiles, ResourceFiles resourceFiles) {
+			SourceFiles sourceFiles, ResourceFiles resourceFiles,
+			List<Processor> processors) {
+
 		this.classLoader = classLoader;
 		this.compiler = compiler;
 		this.sourceFiles = sourceFiles;
 		this.resourceFiles = resourceFiles;
+		this.processors = processors;
 	}
 
 
@@ -83,7 +92,7 @@ public static TestCompiler forSystem() {
 	 */
 	public static TestCompiler forCompiler(JavaCompiler javaCompiler) {
 		return new TestCompiler(null, javaCompiler, SourceFiles.none(),
-				ResourceFiles.none());
+				ResourceFiles.none(), Collections.emptyList());
 	}
 
 	/**
@@ -110,7 +119,7 @@ public TestCompiler withFiles(InMemoryGeneratedFiles generatedFiles) {
 	 */
 	public TestCompiler withSources(SourceFile... sourceFiles) {
 		return new TestCompiler(this.classLoader, this.compiler,
-				this.sourceFiles.and(sourceFiles), this.resourceFiles);
+				this.sourceFiles.and(sourceFiles), this.resourceFiles, this.processors);
 	}
 
 	/**
@@ -120,7 +129,7 @@ public TestCompiler withSources(SourceFile... sourceFiles) {
 	 */
 	public TestCompiler withSources(Iterable<SourceFile> sourceFiles) {
 		return new TestCompiler(this.classLoader, this.compiler,
-				this.sourceFiles.and(sourceFiles), this.resourceFiles);
+				this.sourceFiles.and(sourceFiles), this.resourceFiles, this.processors);
 	}
 
 	/**
@@ -130,7 +139,7 @@ public TestCompiler withSources(Iterable<SourceFile> sourceFiles) {
 	 */
 	public TestCompiler withSources(SourceFiles sourceFiles) {
 		return new TestCompiler(this.classLoader, this.compiler,
-				this.sourceFiles.and(sourceFiles), this.resourceFiles);
+				this.sourceFiles.and(sourceFiles), this.resourceFiles, this.processors);
 	}
 
 	/**
@@ -140,7 +149,7 @@ public TestCompiler withSources(SourceFiles sourceFiles) {
 	 */
 	public TestCompiler withResources(ResourceFile... resourceFiles) {
 		return new TestCompiler(this.classLoader, this.compiler, this.sourceFiles,
-				this.resourceFiles.and(resourceFiles));
+				this.resourceFiles.and(resourceFiles), this.processors);
 	}
 
 	/**
@@ -150,7 +159,7 @@ public TestCompiler withResources(ResourceFile... resourceFiles) {
 	 */
 	public TestCompiler withResources(Iterable<ResourceFile> resourceFiles) {
 		return new TestCompiler(this.classLoader, this.compiler, this.sourceFiles,
-				this.resourceFiles.and(resourceFiles));
+				this.resourceFiles.and(resourceFiles), this.processors);
 	}
 
 	/**
@@ -160,9 +169,32 @@ public TestCompiler withResources(Iterable<ResourceFile> resourceFiles) {
 	 */
 	public TestCompiler withResources(ResourceFiles resourceFiles) {
 		return new TestCompiler(this.classLoader, this.compiler, this.sourceFiles,
-				this.resourceFiles.and(resourceFiles));
+				this.resourceFiles.and(resourceFiles), this.processors);
+	}
+
+	/**
+	 * Return a new {@link TestCompiler} instance with additional annotation processors.
+	 * @param processors the additional annotation processors
+	 * @return a new {@link TestCompiler} instance
+	 */
+	public TestCompiler withProcessors(Processor... processors) {
+		List<Processor> mergedProcessors = new ArrayList<>(this.processors);
+		mergedProcessors.addAll(Arrays.asList(processors));
+		return new TestCompiler(this.classLoader, this.compiler, this.sourceFiles,
+				this.resourceFiles, mergedProcessors);
 	}
 
+	/**
+	 * Return a new {@link TestCompiler} instance with additional annotation processors.
+	 * @param processors the additional annotation processors
+	 * @return a new {@link TestCompiler} instance
+	 */
+	public TestCompiler withProcessors(Iterable<Processor> processors) {
+		List<Processor> mergedProcessors = new ArrayList<>(this.processors);
+		processors.forEach(mergedProcessors::add);
+		return new TestCompiler(this.classLoader, this.compiler, this.sourceFiles,
+				this.resourceFiles, mergedProcessors);
+	}
 
 	/**
 	 * Compile content from this instance along with the additional provided
@@ -244,6 +276,9 @@ private DynamicClassLoader compile() {
 			Errors errors = new Errors();
 			CompilationTask task = this.compiler.getTask(null, fileManager, errors, null,
 					null, compilationUnits);
+			if (!this.processors.isEmpty()) {
+				task.setProcessors(this.processors);
+			}
 			boolean result = task.call();
 			if (!result || errors.hasReportedErrors()) {
 				throw new CompilationException(errors.toString(), this.sourceFiles, this.resourceFiles);

spring-core-test/src/test/java/org/springframework/aot/test/generator/compile/TestCompilerTests.java

@@ -16,8 +16,17 @@
 
 package org.springframework.aot.test.generator.compile;
 
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
 import java.util.function.Supplier;
 
+import javax.annotation.processing.AbstractProcessor;
+import javax.annotation.processing.Processor;
+import javax.annotation.processing.RoundEnvironment;
+import javax.annotation.processing.SupportedAnnotationTypes;
+import javax.lang.model.element.TypeElement;
+
 import com.example.PublicInterface;
 import org.junit.jupiter.api.Test;
 
@@ -33,9 +42,9 @@
 
 /**
  * Tests for {@link TestCompiler}.
- *
  * @author Phillip Webb
  * @author Andy Wilkinson
+ * @author Scott Frederick
  */
 class TestCompilerTests {
 
@@ -140,6 +149,29 @@ void withResourcesAddsResource() {
 				this::assertHasResource);
 	}
 
+	@Test
+	void withProcessorsArrayAddsProcessors() {
+		SourceFile sourceFile = SourceFile.of(HELLO_WORLD);
+		TestProcessor processor = new TestProcessor();
+		TestCompiler.forSystem().withSources(sourceFile).withProcessors(processor).compile((compiled -> {
+			assertThat(processor.getProcessedAnnotations()).isNotEmpty();
+			assertThat(processor.getProcessedAnnotations()).satisfiesExactly(element ->
+					assertThat(element.getQualifiedName().toString()).isEqualTo("java.lang.Deprecated"));
+		}));
+	}
+
+	@Test
+	void withProcessorsAddsProcessors() {
+		SourceFile sourceFile = SourceFile.of(HELLO_WORLD);
+		TestProcessor processor = new TestProcessor();
+		List<Processor> processors = List.of(processor);
+		TestCompiler.forSystem().withSources(sourceFile).withProcessors(processors).compile((compiled -> {
+			assertThat(processor.getProcessedAnnotations()).isNotEmpty();
+			assertThat(processor.getProcessedAnnotations()).satisfiesExactly(element ->
+					assertThat(element.getQualifiedName().toString()).isEqualTo("java.lang.Deprecated"));
+		}));
+	}
+
 	@Test
 	void compileWithWritableContent() {
 		WritableContent content = appendable -> appendable.append(HELLO_WORLD);
@@ -217,4 +249,20 @@ private void assertHasResource(Compiled compiled) {
 				"META-INF/myfile")).hasContent("test");
 	}
 
+	@SupportedAnnotationTypes("java.lang.Deprecated")
+	static class TestProcessor extends AbstractProcessor {
+
+		private final List<TypeElement> processedAnnotations = new ArrayList<>();
+
+		@Override
+		public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+			this.processedAnnotations.addAll(annotations);
+			return true;
+		}
+
+		public List<TypeElement> getProcessedAnnotations() {
+			return this.processedAnnotations;
+		}
+	}
+
 }