[Fix] Fix waiting for databricks_vector_search_index readiness (#4243)

## Changes
<!-- Summary of your changes that are easy to understand -->

Change the wait condition from waiting for the index to be fully ready
to either fully ready or started indexing.

Resolves #4144

## Tests
<!-- 
How is this tested? Please see the checklist below and also describe any
other relevant tests
-->

- [x] `make test` run locally
- [ ] relevant change in `docs/` folder
- [ ] covered with integration tests in `internal/acceptance`
- [x] relevant acceptance tests are passing
- [ ] using Go SDK

Author: alexott

vectorsearch/resource_vector_search_index.go

@@ -37,7 +37,8 @@ func waitForSearchIndexCreation(w *databricks.WorkspaceClient, ctx context.Conte
 		if err != nil {
 			return retry.NonRetryableError(err)
 		}
-		if index.Status.Ready { // We really need to depend on the detailed status of the index, but it's not available in the API yet
+		// We really need to depend on the detailed status of the index, but it's not available in the API yet
+		if index.Status != nil && (index.Status.Ready || index.Status.IndexedRowCount > 0) {
 			return nil
 		}
 		return retry.RetryableError(fmt.Errorf("vector search index %s is still pending", searchIndexName))

vectorsearch/resource_vector_search_index_test.go

@@ -82,6 +82,54 @@ func TestVectorSearchIndexCreate(t *testing.T) {
 	assert.Equal(t, "abc", d.Id())
 }
 
+func TestVectorSearchIndexCreateNotReadyButIndexedRows(t *testing.T) {
+	d, err := qa.ResourceFixture{
+		MockWorkspaceClientFunc: func(w *mocks.MockWorkspaceClient) {
+			e := w.GetMockVectorSearchIndexesAPI().EXPECT()
+			e.CreateIndex(mock.Anything, vectorsearch.CreateVectorIndexRequest{
+				Name:         "abc",
+				EndpointName: "test",
+				PrimaryKey:   "id",
+				IndexType:    "DELTA_SYNC",
+				DeltaSyncIndexSpec: &vectorsearch.DeltaSyncVectorIndexSpecRequest{
+					SourceTable:  "main.default.test",
+					PipelineType: "TRIGGERED",
+					EmbeddingSourceColumns: []vectorsearch.EmbeddingSourceColumn{
+						{
+							Name:                       "text",
+							EmbeddingModelEndpointName: "e5_small_v2",
+						},
+					},
+				},
+			}).Return(&vectorsearch.CreateVectorIndexResponse{}, nil)
+			e.GetIndexByIndexName(mock.Anything, "abc").Return(&vectorsearch.VectorIndex{
+				Name:         "abc",
+				EndpointName: "test",
+				PrimaryKey:   "id",
+				IndexType:    "DELTA_SYNC",
+				DeltaSyncIndexSpec: &vectorsearch.DeltaSyncVectorIndexSpecResponse{
+					SourceTable:  "main.default.test",
+					PipelineType: "TRIGGERED",
+					EmbeddingSourceColumns: []vectorsearch.EmbeddingSourceColumn{
+						{
+							Name:                       "text",
+							EmbeddingModelEndpointName: "e5_small_v2",
+						},
+					},
+				},
+				Status: &vectorsearch.VectorIndexStatus{
+					IndexedRowCount: 10,
+				},
+			}, nil)
+		},
+		Resource: ResourceVectorSearchIndex(),
+		HCL:      indexHcl,
+		Create:   true,
+	}.Apply(t)
+	assert.NoError(t, err)
+	assert.Equal(t, "abc", d.Id())
+}
+
 func TestVectorSearchIndexRead(t *testing.T) {
 	d, err := qa.ResourceFixture{
 		MockWorkspaceClientFunc: func(w *mocks.MockWorkspaceClient) {