resource/aws_db_instance: Adds warning when setting character_set_name on replica- or restore-type resources

.changelog/36518.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+resource/aws_db_instance: Adds warning when setting `character_set_name` when `replicate_source_db`, `restore_to_point_in_time`, or `snapshot_identifier` is set
+```

internal/errs/diag.go

@@ -74,6 +74,21 @@ func withPath(d diag.Diagnostic, path cty.Path) diag.Diagnostic {
 	return d
 }
 
+// newAttributeConflictsError is included for use with NewAttributeConflictsWillBeError.
+// The typical behavior is covered using the schema ConflictsWith parameter.
+func newAttributeConflictsError(path, otherPath cty.Path) diag.Diagnostic {
+	return NewAttributeErrorDiagnostic(
+		path,
+		"Invalid Attribute Combination",
+		fmt.Sprintf("Attribute %q cannot be specified when %q is specified.",
+			PathString(path),
+			PathString(otherPath),
+		),
+	)
+}
+
+// NewAttributeConflictsWhenError returns an error diagnostic indicating that the attribute at the given path cannot be
+// specified when the attribute at otherPath has the given value.
 func NewAttributeConflictsWhenError(path, otherPath cty.Path, otherValue string) diag.Diagnostic {
 	return NewAttributeErrorDiagnostic(
 		path,
@@ -86,18 +101,32 @@ func NewAttributeConflictsWhenError(path, otherPath cty.Path, otherValue string)
 	)
 }
 
-func NewAttributeRequiredWhenError(neededPath, path cty.Path, value string) diag.Diagnostic {
+// NewAttributeRequiredWhenError returns an error diagnostic indicating that the attribute at neededPath is required when the
+// attribute at otherPath has the given value.
+func NewAttributeRequiredWhenError(neededPath, otherPath cty.Path, value string) diag.Diagnostic {
 	return NewAttributeErrorDiagnostic(
-		path,
+		otherPath,
 		"Invalid Attribute Combination",
 		fmt.Sprintf("Attribute %q must be specified when %q is %q.",
 			PathString(neededPath),
-			PathString(path),
+			PathString(otherPath),
 			value,
 		),
 	)
 }
 
+// NewAttributeConflictsWillBeError returns a warning diagnostic indicating that the attribute at the given path cannot be
+// specified when the attribute at otherPath is set.
+// This is intended to be used for situations where the conflict will become an error in a future release.
+func NewAttributeConflictsWillBeError(path, otherPath cty.Path) diag.Diagnostic {
+	return willBeError(
+		newAttributeConflictsError(path, otherPath),
+	)
+}
+
+// NewAttributeConflictsWhenWillBeError returns a warning diagnostic indicating that the attribute at the given path cannot be
+// specified when the attribute at otherPath has the given value.
+// This is intended to be used for situations where the conflict will become an error in a future release.
 func NewAttributeConflictsWhenWillBeError(path, otherPath cty.Path, otherValue string) diag.Diagnostic {
 	return willBeError(
 		NewAttributeConflictsWhenError(path, otherPath, otherValue),

internal/service/rds/instance.go

@@ -21,6 +21,7 @@ import (
 	"github.com/aws/aws-sdk-go/service/rds"
 	"github.com/hashicorp/aws-sdk-go-base/v2/awsv1shim/v2/tfawserr"
 	tfawserr_sdkv2 "github.com/hashicorp/aws-sdk-go-base/v2/tfawserr"
+	"github.com/hashicorp/go-cty/cty"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/customdiff"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/retry"
@@ -152,6 +153,9 @@ func ResourceInstance() *schema.Resource {
 				Computed:     true,
 				ForceNew:     true,
 				ValidateFunc: validation.StringInSlice(backupTarget_Values(), false),
+				ConflictsWith: []string{
+					"s3_import",
+				},
 			},
 			"backup_window": {
 				Type:         schema.TypeString,
@@ -182,6 +186,22 @@ func ResourceInstance() *schema.Resource {
 				Optional: true,
 				Computed: true,
 				ForceNew: true,
+				ConflictsWith: []string{
+					"s3_import",
+				},
+				DiffSuppressFunc: func(k, oldValue, newValue string, d *schema.ResourceData) bool {
+					for _, conflictAttr := range []string{
+						"replicate_source_db",
+						// s3_import is handled by the schema ConflictsWith
+						"snapshot_identifier",
+						"restore_to_point_in_time",
+					} {
+						if _, ok := d.GetOk(conflictAttr); ok {
+							return true
+						}
+					}
+					return false
+				},
 			},
 			"copy_tags_to_snapshot": {
 				Type:     schema.TypeBool,
@@ -628,6 +648,9 @@ func ResourceInstance() *schema.Resource {
 				Optional: true,
 				Computed: true,
 				ForceNew: true,
+				ConflictsWith: []string{
+					"s3_import",
+				},
 			},
 			"username": {
 				Type:          schema.TypeString,
@@ -697,6 +720,23 @@ func resourceInstanceCreate(ctx context.Context, d *schema.ResourceData, meta in
 
 	var resourceID string // will be assigned depending on how it is created
 
+	if _, ok := d.GetOk("character_set_name"); ok {
+		charSetPath := cty.GetAttrPath("character_set_name")
+		for _, conflictAttr := range []string{
+			"replicate_source_db",
+			// s3_import is handled by the schema ConflictsWith
+			"snapshot_identifier",
+			"restore_to_point_in_time",
+		} {
+			if _, ok := d.GetOk(conflictAttr); ok {
+				diags = append(diags, errs.NewAttributeConflictsWillBeError(
+					charSetPath,
+					cty.GetAttrPath(conflictAttr),
+				))
+			}
+		}
+	}
+
 	if v, ok := d.GetOk("replicate_source_db"); ok {
 		sourceDBInstanceID := v.(string)
 		input := &rds.CreateDBInstanceReadReplicaInput{
@@ -902,15 +942,6 @@ func resourceInstanceCreate(ctx context.Context, d *schema.ResourceData, meta in
 		if _, ok := d.GetOk("username"); !ok {
 			diags = sdkdiag.AppendErrorf(diags, `"username": required field is not set`)
 		}
-		if _, ok := d.GetOk("character_set_name"); ok {
-			diags = sdkdiag.AppendErrorf(diags, `"character_set_name" doesn't work with restores"`)
-		}
-		if _, ok := d.GetOk("timezone"); ok {
-			diags = sdkdiag.AppendErrorf(diags, `"timezone" doesn't work with restores"`)
-		}
-		if _, ok := d.GetOk("backup_target"); ok {
-			diags = sdkdiag.AppendErrorf(diags, `"backup_target" doesn't work with restores"`)
-		}
 		if diags.HasError() {
 			return diags
 		}