Do not show single node warning when is_single_node option is explicitly set (#4272)

## Changes
Do not show single node warning when is_single_node option is explicitly
set

## Why
Fixes #4267 

## Tests
Added an unit test

<!-- If your PR needs to be included in the release notes for next
release,
add a separate entry in NEXT_CHANGELOG.md as part of your PR. -->

Author: andrewnester

NEXT_CHANGELOG.md

@@ -10,6 +10,7 @@ To disable this, set the environment variable DATABRICKS_CACHE_ENABLED to false.
 
 ### Bundles
 * Enable caching user identity by default ([#4202](https://github.com/databricks/cli/pull/4202))
+* Do not show single node warning when is_single_node option is explicitly set ([#4272](https://github.com/databricks/cli/pull/4272))
 * Fix false positive folder permission warnings and make them more actionable ([#4216](https://github.com/databricks/cli/pull/4216))
 * Pass additional Azure DevOps system variables ([#4236](https://github.com/databricks/cli/pull/4236))
 * Replace Black formatter with Ruff in Python bundle templates for faster, all-in-one linting and formatting ([#4196](https://github.com/databricks/cli/pull/4196))

bundle/config/validate/single_node_cluster.go

@@ -44,6 +44,13 @@ func showSingleNodeClusterWarning(ctx context.Context, v dyn.Value) bool {
 		return false
 	}
 
+	// If is_single_node is set to true, the cluster is correctly configured automatically.
+	// No need to show the warning.
+	isSingleNode, ok := v.Get("is_single_node").AsBool()
+	if ok && isSingleNode {
+		return false
+	}
+
 	// Convenient type that contains the common fields from compute.ClusterSpec and
 	// pipelines.PipelineCluster that we are interested in.
 	type ClusterConf struct {

bundle/config/validate/single_node_cluster_test.go

@@ -563,3 +563,41 @@ func TestValidateSingleNodeClusterPassJobForEachTaskCluster(t *testing.T) {
 		})
 	}
 }
+
+func TestValidateSingleNodeClusterWithIsSingleNode(t *testing.T) {
+	ctx := context.Background()
+
+	// Test that when is_single_node is set to true, no warning is shown
+	// even if the manual single-node configuration is not present.
+	b := &bundle.Bundle{
+		Config: config.Root{
+			Resources: config.Resources{
+				Jobs: map[string]*resources.Job{
+					"foo": {
+						JobSettings: jobs.JobSettings{
+							JobClusters: []jobs.JobCluster{
+								{
+									NewCluster: compute.ClusterSpec{
+										ClusterName: "my_cluster",
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	// Set num_workers to 0 and is_single_node to true
+	bundletest.Mutate(t, b, func(v dyn.Value) (dyn.Value, error) {
+		v, err := dyn.Set(v, "resources.jobs.foo.job_clusters[0].new_cluster.num_workers", dyn.V(0))
+		if err != nil {
+			return v, err
+		}
+		return dyn.Set(v, "resources.jobs.foo.job_clusters[0].new_cluster.is_single_node", dyn.V(true))
+	})
+
+	diags := bundle.Apply(ctx, b, SingleNodeCluster())
+	assert.Empty(t, diags)
+}