Return empty list for not existing source root location

Author: slawekjaranowski

plexus-compiler-api/src/main/java/org/codehaus/plexus/compiler/AbstractCompiler.java

@@ -25,6 +25,7 @@
  */
 import java.io.File;
 import java.io.IOException;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -145,10 +146,14 @@ public static String getPathString(List<String> pathElements) {
     }
 
     protected static Set<String> getSourceFilesForSourceRoot(CompilerConfiguration config, String sourceLocation) {
-        DirectoryScanner scanner = new DirectoryScanner();
 
+        DirectoryScanner scanner = new DirectoryScanner();
         scanner.setBasedir(sourceLocation);
 
+        if (!scanner.getBasedir().exists()) {
+            return Collections.emptySet();
+        }
+
         Set<String> includes = config.getIncludes();
 
         if (includes != null && !includes.isEmpty()) {

plexus-compiler-api/src/test/java/org/codehaus/plexus/compiler/AbstractCompilerTest.java

@@ -0,0 +1,25 @@
+package org.codehaus.plexus.compiler;
+
+import java.io.File;
+import java.util.Set;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class AbstractCompilerTest {
+
+    @Test
+    void getSourceFilesForSourceRootShouldReturnEmptyForNotExistingLocation() {
+
+        CompilerConfiguration config = new CompilerConfiguration();
+        File fileLocation = new File("non/existing/location").getAbsoluteFile();
+
+        assertFalse(fileLocation.exists());
+
+        Set<String> sourcesFile = AbstractCompiler.getSourceFilesForSourceRoot(config, fileLocation.getAbsolutePath());
+
+        assertTrue(sourcesFile.isEmpty());
+    }
+}