Use Files.deleteIfExists in FileUtils.forceDelete

src/main/java/org/codehaus/plexus/util/FileUtils.java

@@ -66,6 +66,7 @@
 import java.net.URL;
 import java.nio.charset.Charset;
 import java.nio.file.Files;
+import java.nio.file.LinkOption;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardOpenOption;
@@ -1176,45 +1177,53 @@
         if (file.isDirectory()) {
             deleteDirectory(file);
         } else {
-            /*
-             * NOTE: Always try to delete the file even if it appears to be non-existent. This will ensure that a
-             * symlink whose target does not exist is deleted, too.
-             */
-            boolean filePresent = file.getCanonicalFile().exists();
-            if (!deleteFile(file) && filePresent) {
-                final String message = "File " + file + " unable to be deleted.";
-                throw new IOException(message);
+            if (!deleteFile(file)) {
+                throw new IOException("File " + file + " unable to be deleted.");
             }
         }
     }
 
     /**
-     * Accommodate Windows bug encountered in both Sun and IBM JDKs. Others possible. If the delete does not work, call
+     * Deletes a file, or a symlink without following it. A file that does not exist (including a dangling symlink,
+     * which {@link Files#deleteIfExists} removes) counts as deleted and returns immediately. Only if the file still
+     * exists after a failed attempt, accommodate the Windows bug encountered in both Sun and IBM JDKs: call
      * System.gc(), wait a little and try again.
      *
      * @param file a file
+     * @return {@code true} if the file no longer exists
      * @throws IOException if any
      */
     private static boolean deleteFile(File file) throws IOException {
         if (file.isDirectory()) {
             throw new IOException("File " + file + " isn't a file.");
         }
 
-        if (!file.delete()) {
-            if (Os.isFamily(Os.FAMILY_WINDOWS)) {
-                file = file.getCanonicalFile();
-                System.gc();
+        final Path path = file.toPath();
+        try {
+            Files.deleteIfExists(path);
+            return true;
+        } catch (IOException e) {
+            if (!Files.exists(path, LinkOption.NOFOLLOW_LINKS)) {
+                return true;
             }
+        }
 
-            try {
-                Thread.sleep(10);
-                return file.delete();
-            } catch (InterruptedException ignore) {
-                return file.delete();
-            }
+        if (Os.isFamily(Os.FAMILY_WINDOWS)) {
+            System.gc();
         }
 
-        return true;
+        try {
+            Thread.sleep(10);
+        } catch (InterruptedException ignore) {
+            Thread.currentThread().interrupt();
+        }
+
+        try {
+            Files.deleteIfExists(path);
+            return true;
+        } catch (IOException e) {
+            return !Files.exists(path, LinkOption.NOFOLLOW_LINKS);
+        }
     }
 
     /**
@@ -1928,9 +1937,9 @@
                 fileReader = null;
             } finally {
                 //noinspection deprecation
                 IOUtil.close(fileReader);
                 //noinspection deprecation
                 IOUtil.close(fileWriter);
             }
         } else {
             if (isSourceNewerThanDestination(from, to) || overwrite) {

src/test/java/org/codehaus/plexus/util/FileUtilsTest.java

@@ -425,6 +425,28 @@ void forceDeleteAFile2() throws Exception {
         assertFalse(destination.exists(), "Check No Exist");
     }
 
+    @Test
+    void forceDeleteNonExistingFile() throws Exception {
+        final File missing = new File(getTestDirectory(), "does-not-exist.txt");
+        assertFalse(missing.exists());
+        FileUtils.forceDelete(missing);
+        assertFalse(missing.exists());
+    }
+
+    @Test
+    void forceDeleteDanglingSymlink() throws Exception {
+        final File target = new File(getTestDirectory(), "dangling-target.txt");
+        final File symlink = new File(getTestDirectory(), "dangling-link");
+        createFile(target, 1);
+        createSymlink(symlink, target);
+        assumeTrue(Files.isSymbolicLink(symlink.toPath()), "the platform created a real symlink");
+        assertTrue(target.delete());
+        // Windows stops reporting a file link as a symlink once its target is gone
+        assumeTrue(Files.isSymbolicLink(symlink.toPath()), "the platform keeps a dangling symlink");
+        FileUtils.forceDelete(symlink);
+        assertFalse(Files.isSymbolicLink(symlink.toPath()), "Dangling symlink should be removed");
+    }
+
     @Test
     void copyFile1ToDir() throws Exception {
         final File directory = new File(getTestDirectory(), "subdir");