fix(client): don't throw IndexOutOfBoundsException when null writes a…

…nd reads are sent

from openfga/sdk-generator#307

src/main/java/dev/openfga/sdk/api/client/OpenFgaClient.java

@@ -409,6 +409,12 @@ private CompletableFuture<ClientWriteResponse> writeTransactions(
         var deleteTransactions = chunksOf(chunkSize, request.getDeletes()).map(ClientWriteRequest::ofDeletes);
 
         var transactions = Stream.concat(writeTransactions, deleteTransactions).collect(Collectors.toList());
+
+        if (transactions.isEmpty()) {
+            var emptyTransaction = new ClientWriteRequest().writes(null).deletes(null);
+            return this.writeNonTransaction(storeId, emptyTransaction, writeOptions);
+        }
+
         var futureResponse = this.writeNonTransaction(storeId, transactions.get(0), options);
 
         for (int i = 1; i < transactions.size(); i++) {

src/test/java/dev/openfga/sdk/api/client/OpenFgaClientTest.java

@@ -25,6 +25,7 @@
 import dev.openfga.sdk.errors.*;
 import java.net.http.HttpClient;
 import java.time.Duration;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
@@ -1370,6 +1371,25 @@ public void deleteTuplesTest() throws Exception {
         assertEquals(200, response.getStatusCode());
     }
 
+    @Test
+    public void write_nothingSentWhenWritesAndDeletesAreEmpty()
+            throws FgaInvalidParameterException, ExecutionException, InterruptedException {
+        // Given
+        String postPath = String.format("https://localhost/stores/%s/write", DEFAULT_STORE_ID);
+        String expectedBody = String.format(
+                "{\"writes\":null,\"deletes\":null,\"authorization_model_id\":\"%s\"}", DEFAULT_AUTH_MODEL_ID);
+        mockHttpClient.onPost(postPath).withBody(is(expectedBody)).doReturn(200, EMPTY_RESPONSE_BODY);
+
+        // When
+        var clientWriteRequest =
+                new ClientWriteRequest().writes(Collections.emptyList()).deletes(Collections.emptyList());
+        var response = fga.write(clientWriteRequest).get();
+
+        // Then
+        mockHttpClient.verify().post(postPath).called(1);
+        assertEquals(200, response.getStatusCode());
+    }
+
     @Test
     public void write_storeIdRequired() {
         // Given