fix: send clusterId in inline-create boot disk (#3)

The Fluence API's VmBootDisk oneOf create variant is a
CreateUserStorageRequest, which requires clusterId. The inline-create
path built a CreateUserStorageInline without it, so `terraform apply` of
a cloudless_vm with an inline boot_disk failed with:

  400 Input validation error: bootDisk: data did not match any variant
  of untagged enum VmBootDisk

Thread the VM's cluster_id into the inline boot disk so the body matches
the create variant.

The mock server accepted the malformed body (it treats any non-string
bootDisk as an inline create and synthesizes an ID), so this only
surfaced against the real API. Add a bootDiskToAPI unit test asserting
clusterId is populated and marshaled.

Author: gurinderu

internal/client/client.go

@@ -374,6 +374,7 @@ func (b VMBootDisk) MarshalJSON() ([]byte, error) {
 }
 
 type CreateUserStorageInline struct {
+	ClusterID   string `json:"clusterId"`
 	Name        string `json:"name"`
 	StorageType string `json:"storageType"`
 	VolumeGb    uint32 `json:"volumeGb"`

internal/provider/vm_resource.go

@@ -146,8 +146,10 @@ func (r *vmResource) Configure(_ context.Context, req resource.ConfigureRequest,
 
 // bootDiskToAPI translates the Terraform boot_disk block into a VMBootDisk for
 // the Fluence API: existing storage_id wins; otherwise the inline-create
-// fields are required as a set.
-func bootDiskToAPI(d *vmBootDiskModel) (client.VMBootDisk, error) {
+// fields are required as a set. The inline-create variant is a
+// CreateUserStorageRequest, which carries its own clusterId — it inherits the
+// VM's cluster, passed in here.
+func bootDiskToAPI(d *vmBootDiskModel, clusterID string) (client.VMBootDisk, error) {
 	if d == nil {
 		return client.VMBootDisk{}, fmt.Errorf("boot_disk block is required")
 	}
@@ -159,6 +161,7 @@ func bootDiskToAPI(d *vmBootDiskModel) (client.VMBootDisk, error) {
 		return client.VMBootDisk{}, fmt.Errorf("inline boot_disk requires name, storage_type, volume_gb, and replicated")
 	}
 	return client.VMBootDisk{Create: &client.CreateUserStorageInline{
+		ClusterID:   clusterID,
 		Name:        d.Name.ValueString(),
 		StorageType: d.StorageType.ValueString(),
 		VolumeGb:    uint32(d.VolumeGb.ValueInt64()),
@@ -176,7 +179,7 @@ func (r *vmResource) Create(ctx context.Context, req resource.CreateRequest, res
 		return
 	}
 
-	bd, err := bootDiskToAPI(plan.BootDisk)
+	bd, err := bootDiskToAPI(plan.BootDisk, plan.ClusterID.ValueString())
 	if err != nil {
 		resp.Diagnostics.AddAttributeError(path.Root("boot_disk"), "Invalid boot_disk", err.Error())
 		return

internal/provider/vm_resource_internal_test.go

@@ -0,0 +1,48 @@
+package provider
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-framework/types"
+)
+
+// TestBootDiskToAPI_InlineCarriesClusterID guards a regression where the
+// inline-create boot disk was sent without clusterId. The real Fluence API's
+// VmBootDisk oneOf create variant is a CreateUserStorageRequest, which requires
+// clusterId; omitting it produced a 400 "data did not match any variant of
+// untagged enum VmBootDisk" at apply time. The mock server accepted the
+// malformed body, so the gap was only visible against the real API.
+func TestBootDiskToAPI_InlineCarriesClusterID(t *testing.T) {
+	const clusterID = "aaaaaaaa-aaaa-4aaa-8aaa-aaaaaaaaaaaa"
+	d := &vmBootDiskModel{
+		StorageID:   types.StringNull(),
+		Name:        types.StringValue("boot"),
+		StorageType: types.StringValue("NVME"),
+		VolumeGb:    types.Int64Value(40),
+		Replicated:  types.BoolValue(false),
+		OSImage:     types.StringValue("https://example.com/img.qcow2"),
+	}
+
+	bd, err := bootDiskToAPI(d, clusterID)
+	if err != nil {
+		t.Fatalf("bootDiskToAPI returned error: %v", err)
+	}
+	if bd.Create == nil {
+		t.Fatalf("expected an inline-create boot disk, got %+v", bd)
+	}
+	if bd.Create.ClusterID != clusterID {
+		t.Errorf("inline boot disk ClusterID = %q, want %q", bd.Create.ClusterID, clusterID)
+	}
+
+	// The clusterId must survive marshaling so it reaches the API in the
+	// oneOf create variant.
+	out, err := json.Marshal(bd)
+	if err != nil {
+		t.Fatalf("marshal boot disk: %v", err)
+	}
+	if want := `"clusterId":"` + clusterID + `"`; !strings.Contains(string(out), want) {
+		t.Errorf("marshaled boot disk missing %s\n got: %s", want, out)
+	}
+}