feat: block unsupported Gen 2 plans with helpful validation message (IBM-Cloud#6571)

* feat: block unsupported Gen 2 plans with helpful validation message
* Add tests
* Match any gen2 plans

Author: obai-1

ibm/service/database/resource_ibm_database.go

@@ -897,7 +897,7 @@ func ResourceIBMICDValidator() *validate.ResourceValidator {
 	validateSchema = append(validateSchema,
 		validate.ValidateSchema{
 			Identifier:                 "plan",
-			ValidateFunctionIdentifier: validate.ValidateAllowedStringValue,
+			ValidateFunctionIdentifier: validate.ValidateAllowedICDPlanValue,
 			Type:                       validate.TypeString,
 			AllowedValues:              "standard, enterprise, enterprise-sharding, platinum",
 			Required:                   true})

ibm/service/database/resource_ibm_database_postgresql_test.go

@@ -5,6 +5,7 @@ package database_test
 
 import (
 	"fmt"
+	"regexp"
 	"testing"
 
 	acc "github.com/IBM-Cloud/terraform-provider-ibm/ibm/acctest"
@@ -66,6 +67,25 @@ func TestAccIBMDatabaseInstancePostgresBasic(t *testing.T) {
 	})
 }
 
+func TestAccIBMDatabaseInstancePostgresGen2(t *testing.T) {
+	t.Parallel()
+	databaseResourceGroup := "default"
+	rnd := fmt.Sprintf("tf-Pgress-%d", acctest.RandIntRange(10, 100))
+	testName := rnd
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { acc.TestAccPreCheck(t) },
+		Providers:    acc.TestAccProviders,
+		CheckDestroy: testAccCheckIBMDatabaseInstanceDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config:      testAccCheckIBMDatabaseInstancePostgreGen2(databaseResourceGroup, testName),
+				ExpectError: regexp.MustCompile(`The plan "standard-gen2" corresponds to a Gen 2 database\. Gen 2 instances are not supported by the ibm_database resource\.`),
+			},
+		},
+	})
+}
+
 func TestAccIBMDatabaseInstancePostgresGroup(t *testing.T) {
 	t.Parallel()
 	databaseResourceGroup := "default"
@@ -348,6 +368,58 @@ func testAccCheckIBMDatabaseInstancePostgresBasic(databaseResourceGroup string,
 	`, databaseResourceGroup, name, acc.Region())
 }
 
+func testAccCheckIBMDatabaseInstancePostgreGen2(databaseResourceGroup string, name string) string {
+	return fmt.Sprintf(`
+	data "ibm_resource_group" "test_acc" {
+		name = "%[1]s"
+	}
+
+	resource "ibm_database" "%[2]s" {
+		resource_group_id            = data.ibm_resource_group.test_acc.id
+		name                         = "%[2]s"
+		service                      = "databases-for-postgresql"
+		plan                         = "standard-gen2"
+		location                     = "%[3]s"
+		adminpassword                = "secure-Password12345"
+		service_endpoints            = "public"
+		group {
+			group_id = "member"
+
+			memory {
+			  allocation_mb = 4096
+			}
+			host_flavor {
+				id = "multitenant"
+			}
+			disk {
+			  allocation_mb = 10240
+			}
+		}
+		tags                         = ["one:two"]
+		users {
+			name     = "user123"
+			password = "secure-Password12345"
+		}
+		allowlist {
+			address     = "172.168.1.2/32"
+			description = "desc1"
+		}
+		configuration                = <<CONFIGURATION
+		{
+		  "wal_level": "logical",
+		  "max_replication_slots": 21,
+		  "max_wal_senders": 21
+		}
+		CONFIGURATION
+		logical_replication_slot {
+			name = "wj123"
+			database_name = "ibmclouddb"
+			plugin_type = "wal2json"
+		}
+	}
+	`, databaseResourceGroup, name, acc.Region())
+}
+
 func testAccCheckIBMDatabaseInstancePostgresFullyspecified(databaseResourceGroup string, name string) string {
 	return fmt.Sprintf(`
 	data "ibm_resource_group" "test_acc" {

ibm/validate/validators.go

@@ -48,6 +48,36 @@ func validateServiceTags(v interface{}, k string) (ws []string, errors []error)
 	return
 }
 
+func validateAllowedICDPlanValues(validValues []string) schema.SchemaValidateFunc {
+	return func(v interface{}, k string) (ws []string, errors []error) {
+		input := v.(string)
+		gen2Pattern := regexp.MustCompile(`-gen2($|-.+)`)
+		if gen2Pattern.MatchString(input) {
+			errors = append(errors, fmt.Errorf(
+				"The plan %q corresponds to a Gen 2 database. Gen 2 instances are not supported by the ibm_database resource. "+
+					"Use the ibm_resource_instance resource instead for provisioning and management. "+
+					"More info: ibm.biz/Gen2-overview",
+				input,
+			))
+			return
+		}
+
+		existed := false
+		for _, s := range validValues {
+			if s == input {
+				existed = true
+				break
+			}
+		}
+		if !existed {
+			errors = append(errors, fmt.Errorf(
+				"%q must contain a value from %#v, got %q",
+				k, validValues, input))
+		}
+		return
+	}
+}
+
 func ValidateAllowedStringValues(validValues []string) schema.SchemaValidateFunc {
 	return func(v interface{}, k string) (ws []string, errors []error) {
 		input := v.(string)
@@ -1076,6 +1106,7 @@ const (
 	IntAtLeast
 	IntAtMost
 	ValidateAllowedStringValue
+	ValidateAllowedICDPlanValue
 	StringLenBetween
 	ValidateIPorCIDR
 	ValidateCIDRAddress
@@ -1100,7 +1131,7 @@ func (f FunctionIdentifier) MarshalText() ([]byte, error) {
 
 // Use stringer tool to generate this later.
 func (i FunctionIdentifier) String() string {
-	return [...]string{"IntBetween", "IntAtLeast", "IntAtMost", "ValidateAllowedStringValue", "StringLenBetween", "ValidateIPorCIDR", "ValidateCIDRAddress", "ValidateAllowedIntValue", "ValidateRegexpLen", "ValidateRegexp", "ValidateNoZeroValues", "ValidateJSONString", "ValidateJSONParam", "ValidateBindedPackageName", "ValidateOverlappingAddress", "ValidateCloudData"}[i]
+	return [...]string{"IntBetween", "IntAtLeast", "IntAtMost", "ValidateAllowedStringValue", "ValidateAllowedICDPlanValue", "StringLenBetween", "ValidateIPorCIDR", "ValidateCIDRAddress", "ValidateAllowedIntValue", "ValidateRegexpLen", "ValidateRegexp", "ValidateNoZeroValues", "ValidateJSONString", "ValidateJSONParam", "ValidateBindedPackageName", "ValidateOverlappingAddress", "ValidateCloudData"}[i]
 }
 
 // ValueType -- Copied from Terraform for now. You can refer to Terraform ValueType directly.
@@ -1276,6 +1307,9 @@ func invokeValidatorInternal(schema ValidateSchema) schema.SchemaValidateFunc {
 	case ValidateAllowedStringValue:
 		allowedValues := schema.GetValue(AllowedValues)
 		return ValidateAllowedStringValues(allowedValues.([]string))
+	case ValidateAllowedICDPlanValue:
+		allowedValues := schema.GetValue(AllowedValues)
+		return validateAllowedICDPlanValues(allowedValues.([]string))
 	case StringLenBetween:
 		return validation.StringLenBetween(schema.MinValueLength, schema.MaxValueLength)
 	case ValidateIPorCIDR: