fix: fetchin module from the JDT compiler (#3549)

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

@@ -91,8 +91,14 @@ public CompilationUnit[] getCompilationUnits() {
 							} else {
 								lastSlash += 1;
 							}
-							//TODO the module name parsed by JDK compiler is in `this.modNames`
-							compilationUnit.module = CharOperation.subarray(modulePath, lastSlash, modulePath.length);
+
+							if (this.module == null) {
+								compilationUnit.module = CharOperation.subarray(modulePath, lastSlash, modulePath.length);
+							} else {
+								//TODO the module name parsed by JDK compiler is in `this.modNames`, consider using that instead?
+								compilationUnit.module = this.module.name();
+							}
+
 							pathToModName.put(String.valueOf(modulePath), compilationUnit.module);
 						}
 					} else {

src/test/java/spoon/test/compilation/CompilationTest.java

@@ -260,6 +260,21 @@ public CompilationUnit[] getCompilationUnits() {
 
 	}
 
+	@Test
+	public void testModuleResolution() throws InterruptedException {
+		// contract: module name is set from the info extract from the module-info.java file
+		// when such file exists
+		Launcher launcher = new Launcher();
+
+		// contract: ComplianceLevel must be >=9 to build a model from an input resource
+		// that contains module-info.java file(s)
+		launcher.getEnvironment().setComplianceLevel(9);
+		launcher.addInputResource("./src/test/resources/simple-module");
+		launcher.buildModel();
+
+		assertTrue(launcher.getModel().getAllModules().iterator().next().getSimpleName().equals("spoonmod"));
+	}
+
 	@Test
 	public void testFilterResourcesDir() {
 		// shows how to filter input java dir

src/test/resources/simple-module/module-info.java

@@ -0,0 +1,3 @@
+module spoonmod {
+
+}

src/test/resources/simple-module/spoonmod/TestClass.java

@@ -0,0 +1,5 @@
+package spoonmod;
+
+public class TestClass {
+	public TestClass() {}
+}