Fix lookup of a root directory that doesn't exist to always throw NoSuchFileException.

This prevents creation of a new root directory (or file!) using Files.createDirectory
etc. in file systems that support multiple roots.

1 files changed, 3 insertions, 4 deletions

diff --git a/jimfs/src/main/java/com/google/jimfs/internal/FileTree.java b/jimfs/src/main/java/com/google/jimfs/internal/FileTree.java
index 044cbcf..d3eaa55 100644
--- a/jimfs/src/main/java/com/google/jimfs/internal/FileTree.java
+++ b/jimfs/src/main/java/com/google/jimfs/internal/FileTree.java
@@ -98,10 +98,9 @@ final class FileTree {
       // lookup the root directory
       DirectoryEntry entry = superRoot.asDirectoryTable().get(path.root());
       if (entry == null) {
-        // root not found
-        return !names.isEmpty()
-            ? null
-            : new DirectoryEntry(superRoot, path.root(), null);
+        // root not found; always return null as no real parent directory exists
+        // this prevents new roots from being created in file systems supporting multiple roots
+        return null;
       } else if (names.isEmpty()) {
         // root found, no more names to look up
         return entry;