Always send internal_ip_only, if it is set by the user.

This is required because the autogenerated Dataproc API client has `omitempty` on the field. So if the user specifies `internal_ip_only: false`, then it would not get sent to Dataproc. Thus Dataproc uses server-side defaulting. We don't want that. If the user specifies the value, we want to ensure that value is used.

mmv1/third_party/terraform/services/dataproc/resource_dataproc_cluster.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"log"
 	"regexp"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -2177,7 +2178,13 @@ func expandGceClusterConfig(d *schema.ResourceData, config *transport_tpg.Config
 	}
 	if v, ok := cfg["internal_ip_only"]; ok {
 		conf.InternalIpOnly = v.(bool)
+		// Normally default values are omitted. Concretely this means that if v is
+		// false, then it would not get sent on the request to Dataproc. However,
+		// the user has explicitly set internal_ip_only, therefore we need to send
+		// it on the wire to ensure Dataproc does not use server-side defaulting.
+		conf.ForceSendFields = append(conf.ForceSendFields, "InternalIpOnly")
 	}
+
 	if v, ok := cfg["metadata"]; ok {
 		conf.Metadata = tpgresource.ConvertStringMap(v.(map[string]interface{}))
 	}
@@ -3106,11 +3113,18 @@ func flattenGceClusterConfig(d *schema.ResourceData, gcc *dataproc.GceClusterCon
 	}
 
 	gceConfig := map[string]interface{}{
-		"tags":             schema.NewSet(schema.HashString, tpgresource.ConvertStringArrToInterface(gcc.Tags)),
-		"service_account":  gcc.ServiceAccount,
-		"zone":             tpgresource.GetResourceNameFromSelfLink(gcc.ZoneUri),
-		"internal_ip_only": gcc.InternalIpOnly,
-		"metadata":         gcc.Metadata,
+		"tags":            schema.NewSet(schema.HashString, tpgresource.ConvertStringArrToInterface(gcc.Tags)),
+		"service_account": gcc.ServiceAccount,
+		"zone":            tpgresource.GetResourceNameFromSelfLink(gcc.ZoneUri),
+		"metadata":        gcc.Metadata,
+	}
+
+	// InternalIpOnly needs to differentiate between false and unspecified, because
+	// unspecified means server-side defaulting. expandGceClusterConfig will add
+	// "InternalIpOnly" to gcc.ForceSendFields if the value is specified. So use
+	// that to distinguish between the cases.
+	if gcc.InternalIpOnly || slices.Contains(gcc.ForceSendFields, "InternalIpOnly") {
+		gceConfig["internal_ip_only"] = gcc.InternalIpOnly
 	}
 
 	if gcc.NetworkUri != "" {