[IO-796] FileAlreadyExistsException in

PathUtils.createParentDirectories(Path, LinkOption, FileAttribute<?>...)

Author: garydgregory

src/changes/changes.xml

@@ -58,6 +58,9 @@ The <action> type attribute can be add,update,fix,remove.
       <action dev="ggregory" type="fix" due-to="Gary Gregory">
         AbstractOriginSupplier.checkOrigin() now throws IllegalStateException instead of NullPointerException.
       </action>
+      <action issue="IO-796" dev="ggregory" type="fix" due-to="Giacomo Boccardo, Gary Gregory">
+        FileAlreadyExistsException in PathUtils.createParentDirectories(Path, LinkOption, FileAttribute...).
+      </action>
       <!-- ADD -->
       <action dev="ggregory" type="add" due-to="Gary Gregory">
         Add CharSequenceInputStream.Builder.

src/main/java/org/apache/commons/io/file/PathUtils.java

@@ -356,6 +356,9 @@ public static PathCounters countDirectoryAsBigInteger(final Path directory) thro
 
     /**
      * Creates the parent directories for the given {@code path}.
+     * <p>
+     * If the parent directory already exists, then return it.
+     * <p>
      *
      * @param path The path to a file (or directory).
      * @param attrs An optional list of file attributes to set atomically when creating the directories.
@@ -369,6 +372,9 @@ public static Path createParentDirectories(final Path path, final FileAttribute<
 
     /**
      * Creates the parent directories for the given {@code path}.
+     * <p>
+     * If the parent directory already exists, then return it.
+     * <p>
      *
      * @param path The path to a file (or directory).
      * @param linkOption A {@link LinkOption} or null.
@@ -377,10 +383,15 @@ public static Path createParentDirectories(final Path path, final FileAttribute<
      * @throws IOException if an I/O error occurs.
      * @since 2.12.0
      */
-    public static Path createParentDirectories(final Path path, final LinkOption linkOption, final FileAttribute<?>... attrs) throws IOException {
+    public static Path createParentDirectories(final Path path, final LinkOption linkOption,
+            final FileAttribute<?>... attrs) throws IOException {
         Path parent = getParent(path);
         parent = linkOption == LinkOption.NOFOLLOW_LINKS ? parent : readIfSymbolicLink(parent);
-        return parent == null ? null : Files.createDirectories(parent, attrs);
+        if (parent == null) {
+            return null;
+        }
+        final boolean exists = linkOption == null ? Files.exists(parent) : Files.exists(parent, linkOption);
+        return exists ? parent : Files.createDirectories(parent, attrs);
     }
 
     /**

src/test/java/org/apache/commons/io/file/PathUtilsTest.java

@@ -24,7 +24,6 @@
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertThrowsExactly;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
@@ -36,7 +35,6 @@
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.DirectoryStream;
-import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.FileSystem;
 import java.nio.file.FileSystems;
 import java.nio.file.Files;
@@ -244,7 +242,7 @@ public void testCreateDirectoriesSymlink() throws IOException {
     @Test
     public void testCreateDirectoriesSymlinkClashing() throws IOException {
         final Path symlinkedDir = createTempSymlinkedRelativeDir();
-        assertThrowsExactly(FileAlreadyExistsException.class, () -> PathUtils.createParentDirectories(symlinkedDir.resolve("child")));
+        assertEquals(symlinkedDir, PathUtils.createParentDirectories(symlinkedDir.resolve("child")));
     }
 
     @Test