fix(config.update): guard against null quantizer

Author: bevzzz

src/it/java/io/weaviate/containers/Weaviate.java

@@ -19,6 +19,8 @@
 import io.weaviate.ConcurrentTest;
 import io.weaviate.client6.v1.api.Config;
 import io.weaviate.client6.v1.api.WeaviateClient;
+import io.weaviate.client6.v1.api.collections.Generative;
+import io.weaviate.client6.v1.api.collections.Reranker;
 import io.weaviate.client6.v1.internal.ObjectBuilder;
 import io.weaviate.client6.v1.internal.VersionSupport.SemanticVersion;
 
@@ -154,6 +156,7 @@ public static class Builder {
     private Map<String, String> environment = new HashMap<>();
 
     public Builder() {
+      addModules(Reranker.Kind.DUMMY.jsonValue(), Generative.Kind.DUMMY.jsonValue());
       enableAutoSchema(false);
     }
 

src/it/java/io/weaviate/integration/CollectionsITest.java

@@ -11,6 +11,7 @@
 import io.weaviate.client6.v1.api.WeaviateClient;
 import io.weaviate.client6.v1.api.collections.CollectionConfig;
 import io.weaviate.client6.v1.api.collections.DataType;
+import io.weaviate.client6.v1.api.collections.Generative;
 import io.weaviate.client6.v1.api.collections.InvertedIndex;
 import io.weaviate.client6.v1.api.collections.Property;
 import io.weaviate.client6.v1.api.collections.Quantization;
@@ -19,6 +20,7 @@
 import io.weaviate.client6.v1.api.collections.VectorConfig;
 import io.weaviate.client6.v1.api.collections.config.Shard;
 import io.weaviate.client6.v1.api.collections.config.ShardStatus;
+import io.weaviate.client6.v1.api.collections.generative.DummyGenerative;
 import io.weaviate.client6.v1.api.collections.vectorindex.Hnsw;
 import io.weaviate.client6.v1.api.collections.vectorizers.SelfProvidedVectorizer;
 import io.weaviate.containers.Container;
@@ -234,7 +236,7 @@ public void testNestedProperties() throws IOException {
   }
 
   @Test
-  public void test_updateQuantization() throws IOException {
+  public void test_updateQuantization_uncompressed() throws IOException {
     // Arrange
     var nsThings = ns("Things");
 
@@ -255,4 +257,22 @@ public void test_updateQuantization() throws IOException {
         .extracting(VectorConfig::quantization)
         .returns(Quantization.Kind.BQ, Quantization::_kind);
   }
+
+  @Test
+  public void test_updateGenerative() throws IOException {
+    // Arrange
+    var nsThings = ns("Things");
+
+    var things = client.collections.create(nsThings,
+        c -> c.vectorConfig(VectorConfig.selfProvided()));
+
+    // Act
+    things.config.update(c -> c.generativeModule(new DummyGenerative()));
+
+    // Assert
+    var config = things.config.get();
+    Assertions.assertThat(config).get()
+        .extracting(CollectionConfig::generativeModule).isNotNull()
+        .returns(Generative.Kind.DUMMY, Generative::_kind);
+  }
 }

src/main/java/io/weaviate/client6/v1/api/collections/config/UpdateCollectionRequest.java

@@ -40,7 +40,7 @@ public record UpdateCollectionRequest(CollectionConfig updated, CollectionConfig
           for (var origVector : request.original.vectors().entrySet()) {
             var vectorName = origVector.getKey();
             var origQuantization = origVector.getValue().quantization();
-            if (vectors.has(vectorName)) {
+            if (vectors.has(vectorName) && origQuantization != null) {
               vectors
                   .get(vectorName).getAsJsonObject()
                   .get("vectorIndexConfig").getAsJsonObject()