refactor: Replace CreateOnlyAttributePlanModifier with CreateOnlyStringPlanModifier and add CreateOnlyBoolPlanModifier

Author: EspenAlbert

internal/common/customplanmodifier/create_only.go renamed to internal/common/customplanmodifier/create_only_bool.go

@@ -12,59 +12,45 @@ import (
 	"github.com/hashicorp/terraform-plugin-framework/types"
 )
 
-// CreateOnlyStringPlanModifier creates a plan modifier that prevents updates to string attributes.
-func CreateOnlyStringPlanModifier() planmodifier.String {
-	return &createOnlyAttributePlanModifier{}
-}
-
 // CreateOnlyBoolPlanModifier creates a plan modifier that prevents updates to boolean attributes.
-func CreateOnlyBoolPlanModifier() planmodifier.Bool {
-	return &createOnlyAttributePlanModifier{}
-}
-
-type CreateOnlyModifier interface {
-	planmodifier.String
-	planmodifier.Bool
-}
-
-// CreateOnlyAttributePlanModifier returns a plan modifier that ensures that update operations fails when the attribute is changed.
 // This is useful for attributes only supported in create and not in update.
 // It shows a helpful error message helping the user to update their config to match the state.
-// Never use a schema.Default for create only attributes, instead use WithXXXDefault, the default will lead to plan changes that are not expected after import.
+// Never use a schema.Default for create only attributes, instead use `WithDefault`, the default will lead to plan changes that are not expected after import.
 // Implement CopyFromPlan if the attribute is not in the API Response.
-func CreateOnlyAttributePlanModifier() CreateOnlyModifier {
-	return &createOnlyAttributePlanModifier{}
+func CreateOnlyBoolPlanModifier() planmodifier.Bool {
+	return &createOnlyBoolPlanModifier{}
 }
 
 // CreateOnlyBoolWithDefaultPlanModifier sets a default value on create operation that will show in the plan.
 // This avoids any custom logic in the resource "Create" handler.
 // On update the default has no impact and the UseStateForUnknown behavior is observed instead.
 // Always use Optional+Computed when using a default value.
-func CreateOnlyBoolWithDefaultPlanModifier(b bool) CreateOnlyModifier {
-	return &createOnlyAttributePlanModifier{defaultBool: &b}
+func CreateOnlyBoolWithDefaultPlanModifier(b bool) planmodifier.Bool {
+	return &createOnlyBoolPlanModifier{defaultBool: &b}
 }
 
-type createOnlyAttributePlanModifier struct {
+type createOnlyBoolPlanModifier struct {
 	defaultBool *bool
 }
 
-func (d *createOnlyAttributePlanModifier) Description(ctx context.Context) string {
+func (d *createOnlyBoolPlanModifier) Description(ctx context.Context) string {
 	return d.MarkdownDescription(ctx)
 }
 
-func (d *createOnlyAttributePlanModifier) MarkdownDescription(ctx context.Context) string {
+func (d *createOnlyBoolPlanModifier) MarkdownDescription(ctx context.Context) string {
 	return "Ensures the update operation fails when updating an attribute. If the read after import don't equal the configuration value it will also raise an error."
 }
 
+// isCreate uses the full state to check if this is a create operation
 func isCreate(t *tfsdk.State) bool {
 	return t.Raw.IsNull()
 }
 
-func (d *createOnlyAttributePlanModifier) UseDefault() bool {
+func (d *createOnlyBoolPlanModifier) UseDefault() bool {
 	return d.defaultBool != nil
 }
 
-func (d *createOnlyAttributePlanModifier) PlanModifyBool(ctx context.Context, req planmodifier.BoolRequest, resp *planmodifier.BoolResponse) {
+func (d *createOnlyBoolPlanModifier) PlanModifyBool(ctx context.Context, req planmodifier.BoolRequest, resp *planmodifier.BoolResponse) {
 	if isCreate(&req.State) {
 		if !IsKnown(req.PlanValue) && d.UseDefault() {
 			resp.PlanValue = types.BoolPointerValue(d.defaultBool)
@@ -79,7 +65,7 @@ func (d *createOnlyAttributePlanModifier) PlanModifyBool(ctx context.Context, re
 	}
 }
 
-func (d *createOnlyAttributePlanModifier) PlanModifyString(ctx context.Context, req planmodifier.StringRequest, resp *planmodifier.StringResponse) {
+func (d *createOnlyBoolPlanModifier) PlanModifyString(ctx context.Context, req planmodifier.StringRequest, resp *planmodifier.StringResponse) {
 	if isCreate(&req.State) {
 		return
 	}
@@ -91,14 +77,18 @@ func (d *createOnlyAttributePlanModifier) PlanModifyString(ctx context.Context,
 	}
 }
 
+// isUpdated checks if the attribute was updated.
+// Special case when the attribute is removed/set to null in the plan:
+// Computed Attribute: returns false (unknown in the plan)
+// Optional Attribute: returns true if the state has a value
 func isUpdated(state, plan attr.Value) bool {
 	if !IsKnown(plan) {
 		return false
 	}
 	return !state.Equal(plan)
 }
 
-func (d *createOnlyAttributePlanModifier) addDiags(diags *diag.Diagnostics, attrPath path.Path, stateValue attr.Value) {
+func (d *createOnlyBoolPlanModifier) addDiags(diags *diag.Diagnostics, attrPath path.Path, stateValue attr.Value) {
 	message := fmt.Sprintf("%s cannot be updated or set after import, remove it from the configuration or use the state value (see below).", attrPath)
 	detail := fmt.Sprintf("The current state value is %s", stateValue)
 	diags.AddError(message, detail)

internal/common/customplanmodifier/create_only_string.go

@@ -0,0 +1,49 @@
+package customplanmodifier
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hashicorp/terraform-plugin-framework/attr"
+	"github.com/hashicorp/terraform-plugin-framework/diag"
+	"github.com/hashicorp/terraform-plugin-framework/path"
+	planmodifier "github.com/hashicorp/terraform-plugin-framework/resource/schema/planmodifier"
+)
+
+// CreateOnlyStringPlanModifier creates a plan modifier that prevents updates to string attributes.
+// This is useful for attributes only supported in create and not in update.
+// It shows a helpful error message helping the user to update their config to match the state.
+// Never use a schema.Default for create only attributes, instead use `WithDefault`, the default will lead to plan changes that are not expected after import.
+// No default value implemented for string until we have a use case.
+// Implement CopyFromPlan if the attribute is not in the API Response.
+func CreateOnlyStringPlanModifier() planmodifier.String {
+	return &createOnlyStringPlanModifier{}
+}
+
+type createOnlyStringPlanModifier struct{}
+
+func (d *createOnlyStringPlanModifier) Description(ctx context.Context) string {
+	return d.MarkdownDescription(ctx)
+}
+
+func (d *createOnlyStringPlanModifier) MarkdownDescription(ctx context.Context) string {
+	return "Ensures the update operation fails when updating an attribute. If the read after import don't equal the configuration value it will also raise an error."
+}
+
+func (d *createOnlyStringPlanModifier) PlanModifyString(ctx context.Context, req planmodifier.StringRequest, resp *planmodifier.StringResponse) {
+	if isCreate(&req.State) {
+		return
+	}
+	if isUpdated(req.StateValue, req.PlanValue) {
+		d.addDiags(&resp.Diagnostics, req.Path, req.StateValue)
+	}
+	if !IsKnown(req.PlanValue) {
+		resp.PlanValue = req.StateValue
+	}
+}
+
+func (d *createOnlyStringPlanModifier) addDiags(diags *diag.Diagnostics, attrPath path.Path, stateValue attr.Value) {
+	message := fmt.Sprintf("%s cannot be updated or set after import, remove it from the configuration or use the state value (see below).", attrPath)
+	detail := fmt.Sprintf("The current state value is %s", stateValue)
+	diags.AddError(message, detail)
+}

internal/service/flexcluster/resource_schema.go

@@ -59,7 +59,7 @@ func ResourceSchema(ctx context.Context) schema.Schema {
 					"region_name": schema.StringAttribute{
 						Required: true,
 						PlanModifiers: []planmodifier.String{
-							customplanmodifier.CreateOnlyAttributePlanModifier(),
+							customplanmodifier.CreateOnlyStringPlanModifier(),
 						},
 						MarkdownDescription: "Human-readable label that identifies the geographic location of your MongoDB flex cluster. The region you choose can affect network latency for clients accessing your databases. For a complete list of region names, see [AWS](https://docs.atlas.mongodb.com/reference/amazon-aws/#std-label-amazon-aws), [GCP](https://docs.atlas.mongodb.com/reference/google-gcp/), and [Azure](https://docs.atlas.mongodb.com/reference/microsoft-azure/).",
 					},