From 7c386292bc8b3dfa532bd779d703ee27a5ecf827 Mon Sep 17 00:00:00 2001
From: Norman Rzepka <code@normanrz.com>
Date: Thu, 30 Apr 2026 10:41:37 +0200
Subject: [PATCH] fixes #72

---
 .../zarr/zarrjava/store/BufferedZipStore.java    |  4 ++--
 .../zarrjava/store/BufferedZipStoreTest.java     | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/main/java/dev/zarr/zarrjava/store/BufferedZipStore.java b/src/main/java/dev/zarr/zarrjava/store/BufferedZipStore.java
index ab1afc8c..411bfa2d 100644
--- a/src/main/java/dev/zarr/zarrjava/store/BufferedZipStore.java
+++ b/src/main/java/dev/zarr/zarrjava/store/BufferedZipStore.java
@@ -80,7 +80,7 @@ public BufferedZipStore(@Nonnull StoreHandle underlyingStore) {
     }
 
     public BufferedZipStore(@Nonnull Path underlyingStore, String archiveComment) {
-        this(new FilesystemStore(underlyingStore.getParent()).resolve(underlyingStore.getFileName().toString()), archiveComment);
+        this(new FilesystemStore(underlyingStore.toAbsolutePath().getParent()).resolve(underlyingStore.getFileName().toString()), archiveComment);
     }
 
     public BufferedZipStore(@Nonnull Path underlyingStore) {
@@ -108,7 +108,7 @@ public BufferedZipStore(@Nonnull StoreHandle underlyingStore, boolean flushOnWri
     }
 
     public BufferedZipStore(@Nonnull Path underlyingStore, String archiveComment, boolean flushOnWrite) {
-        this(new FilesystemStore(underlyingStore.getParent()).resolve(underlyingStore.getFileName().toString()), archiveComment, flushOnWrite);
+        this(new FilesystemStore(underlyingStore.toAbsolutePath().getParent()).resolve(underlyingStore.getFileName().toString()), archiveComment, flushOnWrite);
     }
 
     public BufferedZipStore(@Nonnull Path underlyingStore, boolean flushOnWrite) {
diff --git a/src/test/java/dev/zarr/zarrjava/store/BufferedZipStoreTest.java b/src/test/java/dev/zarr/zarrjava/store/BufferedZipStoreTest.java
index 742a18da..88ab1d65 100644
--- a/src/test/java/dev/zarr/zarrjava/store/BufferedZipStoreTest.java
+++ b/src/test/java/dev/zarr/zarrjava/store/BufferedZipStoreTest.java
@@ -15,6 +15,7 @@
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.zip.ZipEntry;
@@ -174,6 +175,21 @@ public void testZipStoreV2(boolean flushOnWrite) throws ZarrException, IOExcepti
     }
 
 
+    @Test
+    public void testBufferedZipStoreWithRelativePath() throws ZarrException, IOException {
+        // Path.of("filename.zip") has no parent component — getParent() returns null,
+        // which previously caused a NullPointerException in FilesystemStore.resolveKeys().
+        Path relPath = Paths.get("testRelativePath.zip");
+        Path absPath = relPath.toAbsolutePath();
+        try {
+            BufferedZipStore store = new BufferedZipStore(relPath);
+            writeTestGroupV3(store.resolve(), true);
+            store.flush();
+        } finally {
+            Files.deleteIfExists(absPath);
+        }
+    }
+
     @Override
     Store writableStore() {
         Path path = TESTOUTPUT.resolve("writableStore.ZIP");