fix: Fix NPE due to duplicated package-info.java with setIgnoreDuplic…

…ateDeclarations(true) (#3791)

src/main/java/spoon/support/compiler/jdt/JDTTreeBuilder.java

@@ -1728,15 +1728,14 @@ public boolean visit(TypeDeclaration memberTypeDeclaration, ClassScope scope) {
 
 	@Override
 	public boolean visit(TypeDeclaration typeDeclaration, CompilationUnitScope scope) {
-		if ("package-info".equals(new String(typeDeclaration.name))) {
+		if (typeDeclaration.binding == null && getFactory().getEnvironment().isIgnoreDuplicateDeclarations()) {
+			// skip the type declaration that are already declared
+			return false;
+		} else if ("package-info".equals(new String(typeDeclaration.name))) {
 			context.enter(factory.Package().getOrCreate(new String(typeDeclaration.binding.fPackage.readableName())), typeDeclaration);
 			return true;
 		} else {
 			CtModule module;
-			// skip the type declaration that are already declared
-			if (typeDeclaration.binding == null && getFactory().getEnvironment().isIgnoreDuplicateDeclarations()) {
-				return false;
-			}
 			if (typeDeclaration.binding.module != null && !typeDeclaration.binding.module.isUnnamed() && typeDeclaration.binding.module.shortReadableName() != null && typeDeclaration.binding.module.shortReadableName().length > 0) {
 				module = factory.Module().getOrCreate(String.valueOf(typeDeclaration.binding.module.shortReadableName()));
 			} else {
@@ -1754,7 +1753,6 @@ public boolean visit(TypeDeclaration typeDeclaration, CompilationUnitScope scope
 			return true;
 		}
 	}
-
 	@Override
 	public boolean visit(UnaryExpression unaryExpression, BlockScope scope) {
 		CtUnaryOperator<?> op = factory.Core().createUnaryOperator();

src/test/java/spoon/test/pkg/PackageTest.java

@@ -28,6 +28,7 @@
 import spoon.reflect.declaration.CtAnnotation;
 import spoon.reflect.declaration.CtAnnotationType;
 import spoon.reflect.declaration.CtClass;
+import spoon.reflect.declaration.CtCompilationUnit;
 import spoon.reflect.declaration.CtField;
 import spoon.reflect.declaration.CtPackage;
 import spoon.reflect.factory.Factory;
@@ -46,9 +47,11 @@
 import java.io.File;
 import java.io.FileReader;
 import java.nio.file.Files;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
+import static org.hamcrest.CoreMatchers.equalTo;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
@@ -148,6 +151,22 @@ public void testPrintPackageInfoWhenNothingInPackage() {
 
 		assertThat(aPackage).isEqualTo(ModelUtils.build(new File("./target/spooned/package/spoon/test/pkg/testclasses/internal")).Package().get("spoon.test.pkg.testclasses.internal"));
 	}
+
+	@Test
+	public void testHandlesDuplicatePackageInfo(){
+		// contract: with setIgnoreDuplicateDeclarations(true), duplicated package-info.java files should be allowed
+
+		final Launcher launcher = new Launcher();
+		launcher.getEnvironment().setIgnoreDuplicateDeclarations(true);
+		launcher.addInputResource("./src/test/resources/duplicate-package-info");
+		launcher.run();
+
+		List<CtCompilationUnit> compilationUnits = new ArrayList<>(launcher.getFactory().CompilationUnit().getMap().values());
+
+		org.hamcrest.MatcherAssert.assertThat(compilationUnits.size(), equalTo(2));
+		compilationUnits.forEach(
+				cu -> org.hamcrest.MatcherAssert.assertThat(cu.getFile().getName(), equalTo("package-info.java")));
+	}
 
 	@Test
 	public void testAnnotationInPackageInfoWhenTemplatesCompiled() throws Exception {

src/test/resources/duplicate-package-info/subproj-A/org/pkg/package-info.java

@@ -0,0 +1 @@
+package org.pkg;

src/test/resources/duplicate-package-info/subproj-B/org/pkg/package-info.java

@@ -0,0 +1 @@
+package org.pkg;