fix(user_tools): handle zero-worker Databricks clusters

user_tools/src/spark_rapids_pytools/cloud_api/databricks_aws.py

@@ -193,7 +193,7 @@ def _set_name_from_props(self) -> None:
     def _init_nodes(self):
         # assume that only one master node
         master_nodes_from_conf = self.props.get_value_silent('driver')
-        worker_nodes_from_conf = self.props.get_value_silent('executors')
+        worker_nodes_from_conf = self.props.get_value_silent('executors') or []
         num_workers = self.props.get_value_silent('num_workers')
         if num_workers is None and self.props.get_value_silent('autoscale') is not None:
             target_workers = self.props.get_value_silent('autoscale', 'target_workers')

user_tools/src/spark_rapids_pytools/cloud_api/databricks_azure.py

@@ -244,7 +244,7 @@ def _set_name_from_props(self) -> None:
     def _init_nodes(self):
         # assume that only one driver node
         driver_nodes_from_conf = self.props.get_value_silent('driver')
-        worker_nodes_from_conf = self.props.get_value_silent('executors')
+        worker_nodes_from_conf = self.props.get_value_silent('executors') or []
         num_workers = self.props.get_value_silent('num_workers')
         if num_workers is None and self.props.get_value_silent('autoscale') is not None:
             target_workers = self.props.get_value_silent('autoscale', 'target_workers')

user_tools/tests/spark_rapids_tools_ut/test_cluster.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2023-2025, NVIDIA CORPORATION.
+# Copyright (c) 2023-2026, NVIDIA CORPORATION.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -14,11 +14,16 @@
 
 """Test Identifying cluster from properties"""
 
+import json
+from types import SimpleNamespace
+
 import pytest
 
 from spark_rapids_tools import CspPath
 from spark_rapids_tools.cloud import ClientCluster
 from spark_rapids_tools.exceptions import InvalidPropertiesSchema
+from spark_rapids_pytools.cloud_api.databricks_aws import DatabricksCluster, DatabricksNode
+from spark_rapids_pytools.cloud_api.databricks_azure import DatabricksAzureCluster, DatabricksAzureNode
 from .conftest import SparkRapidsToolsUT, all_cpu_cluster_props
 
 
@@ -36,3 +41,25 @@ def test_cluster_invalid_path(self, get_ut_data_dir):
     def test_define_cluster_type_from_schema(self, csp, prop_path, get_ut_data_dir):
         client_cluster = ClientCluster(CspPath(f'{get_ut_data_dir}/{prop_path}'))
         assert client_cluster.platform_name == csp
+
+    @pytest.mark.parametrize(
+        ('cluster_type', 'node_type', 'prop_path'),
+        [
+            (DatabricksCluster, DatabricksNode, 'cluster/databricks/aws-cpu-00.json'),
+            (DatabricksAzureCluster, DatabricksAzureNode, 'cluster/databricks/azure-cpu-00.json'),
+        ],
+    )
+    def test_databricks_zero_worker_cluster_reports_validation_error(
+            self, monkeypatch, get_ut_data_dir, cluster_type, node_type, prop_path):
+        cluster_props = json.loads((get_ut_data_dir / prop_path).read_text(encoding='utf-8'))
+        cluster_props.pop('executors')
+        cluster_props['num_workers'] = 0
+
+        platform = SimpleNamespace(cli=SimpleNamespace(
+            get_region=lambda: 'test-region',
+            get_env_var=lambda _: 'test-region',
+        ))
+        monkeypatch.setattr(node_type, 'fetch_and_set_hw_info', lambda *_: None)
+
+        with pytest.raises(RuntimeError, match='The cluster has no worker nodes'):
+            cluster_type(platform).set_connection(props=json.dumps(cluster_props))