Consider Explicit Error Diagnostics When MoveResourceState/ReadResource/UpgradeResourceState Response State Includes Unknown Value

[bflad]

Module version

v1.4.1

Relevant provider source code

ReadResource case:

package provider

import (
	"context"

	"github.com/hashicorp/terraform-plugin-framework/resource"
	"github.com/hashicorp/terraform-plugin-framework/resource/schema"
	"github.com/hashicorp/terraform-plugin-framework/types"
)

var (
	_ resource.Resource = &Testing262Resource{}
)

func NewTesting262Resource() resource.Resource {
	return &Testing262Resource{}
}

type Testing262Resource struct{}

func (r *Testing262Resource) Metadata(_ context.Context, req resource.MetadataRequest, resp *resource.MetadataResponse) {
	resp.TypeName = req.ProviderTypeName + "_testing262"
}

func (r *Testing262Resource) Schema(_ context.Context, _ resource.SchemaRequest, resp *resource.SchemaResponse) {
	resp.Schema = schema.Schema{
		Attributes: map[string]schema.Attribute{
			"required_string": schema.StringAttribute{
				Required: true,
			},
		},
	}
}

func (r Testing262Resource) Create(ctx context.Context, req resource.CreateRequest, resp *resource.CreateResponse) {
	var data Testing262ResourceModel

	resp.Diagnostics.Append(req.Plan.Get(ctx, &data)...)

	if resp.Diagnostics.HasError() {
		return
	}

	resp.Diagnostics.Append(resp.State.Set(ctx, data)...)
}

func (r Testing262Resource) Read(ctx context.Context, req resource.ReadRequest, resp *resource.ReadResponse) {
	var data Testing262ResourceModel

	resp.Diagnostics.Append(req.State.Get(ctx, &data)...)

	if resp.Diagnostics.HasError() {
		return
	}

	// intentionally invalid implementation for example code
	data.RequiredString = types.StringUnknown()

	resp.Diagnostics.Append(resp.State.Set(ctx, data)...)
}

func (r Testing262Resource) Update(ctx context.Context, req resource.UpdateRequest, resp *resource.UpdateResponse) {
	var data Testing262ResourceModel

	resp.Diagnostics.Append(req.Plan.Get(ctx, &data)...)

	if resp.Diagnostics.HasError() {
		return
	}

	resp.Diagnostics.Append(resp.State.Set(ctx, data)...)
}

func (r Testing262Resource) Delete(ctx context.Context, req resource.DeleteRequest, resp *resource.DeleteResponse) {
	var data Testing262ResourceModel

	resp.Diagnostics.Append(req.State.Get(ctx, &data)...)
}

type Testing262ResourceModel struct {
	RequiredString types.String `tfsdk:"required_string"`
}

UpgradeResourceState case:

package provider

import (
	"context"

	"github.com/hashicorp/terraform-plugin-framework/resource"
	"github.com/hashicorp/terraform-plugin-framework/resource/schema"
	"github.com/hashicorp/terraform-plugin-framework/types"
)

var (
	_ resource.Resource                 = &Testing262Resource{}
	_ resource.ResourceWithUpgradeState = &Testing262Resource{}
)

func NewTesting262Resource() resource.Resource {
	return &Testing262Resource{}
}

type Testing262Resource struct{}

func (r *Testing262Resource) Metadata(_ context.Context, req resource.MetadataRequest, resp *resource.MetadataResponse) {
	resp.TypeName = req.ProviderTypeName + "_testing262"
}

func (r *Testing262Resource) Schema(_ context.Context, _ resource.SchemaRequest, resp *resource.SchemaResponse) {
	resp.Schema = schema.Schema{
		Attributes: map[string]schema.Attribute{
			"required_string": schema.StringAttribute{
				Required: true,
			},
		},
		Version: 1, // remove for prior version apply
	}
}

func (r Testing262Resource) Create(ctx context.Context, req resource.CreateRequest, resp *resource.CreateResponse) {
	var data Testing262ResourceModel

	resp.Diagnostics.Append(req.Plan.Get(ctx, &data)...)

	if resp.Diagnostics.HasError() {
		return
	}

	resp.Diagnostics.Append(resp.State.Set(ctx, data)...)
}

func (r Testing262Resource) Read(ctx context.Context, req resource.ReadRequest, resp *resource.ReadResponse) {
	var data Testing262ResourceModel

	resp.Diagnostics.Append(req.State.Get(ctx, &data)...)

	if resp.Diagnostics.HasError() {
		return
	}

	resp.Diagnostics.Append(resp.State.Set(ctx, data)...)
}

func (r Testing262Resource) Update(ctx context.Context, req resource.UpdateRequest, resp *resource.UpdateResponse) {
	var data Testing262ResourceModel

	resp.Diagnostics.Append(req.Plan.Get(ctx, &data)...)

	if resp.Diagnostics.HasError() {
		return
	}

	resp.Diagnostics.Append(resp.State.Set(ctx, data)...)
}

func (r Testing262Resource) Delete(ctx context.Context, req resource.DeleteRequest, resp *resource.DeleteResponse) {
	var data Testing262ResourceModel

	resp.Diagnostics.Append(req.State.Get(ctx, &data)...)
}

func (r Testing262Resource) UpgradeState(ctx context.Context) map[int64]resource.StateUpgrader {
	return map[int64]resource.StateUpgrader{
		0: {
			// Same version 0 and version 1 schema for example simplicity
			PriorSchema: &schema.Schema{
				Attributes: map[string]schema.Attribute{
					"required_string": schema.StringAttribute{
						Required: true,
					},
				},
			},
			StateUpgrader: func(ctx context.Context, req resource.UpgradeStateRequest, resp *resource.UpgradeStateResponse) {
				var data Testing262ResourceModel

				resp.Diagnostics.Append(req.State.Get(ctx, &data)...)

				if resp.Diagnostics.HasError() {
					return
				}

				// intentionally invalid implementation for example code
				data.RequiredString = types.StringUnknown()

				resp.Diagnostics.Append(resp.State.Set(ctx, data)...)
			},
		},
	}
}

type Testing262ResourceModel struct {
	RequiredString types.String `tfsdk:"required_string"`
}

Terraform Configuration Files

resource "framework_testing262" "test" {
  required_string = "test"
}

Expected Behavior

The framework should let provider developers know when their managed resource Read or UpgradeState method implementations are incorrect. This is preferable to happen in the framework since Terraform core does not raise its own error currently, which means that even if/when it does, it will only occur in upgraded Terraform environments.

This can be implemented by walking the response states and raising error diagnostics for all unknown values encountered. This should prevent Terraform from saving the errant state while also notifying practitioners and developers with explicit messaging about the problem.

Actual Behavior

Weird behaviors next terraform plan as noted in hashicorp/terraform#34502 (confusing error after errant Read) and hashicorp/terraform#34503 (confusing plan after errant UpgradeState).

Steps to Reproduce

1. terraform apply
2. terraform plan

References

• Failed to marshal plan to json: value is not known on terraform-plugin-testing@v1.6.0 terraform-plugin-testing#262
• Return Explicit Error Diagnostic When ReadResource Response State Includes Unknown Value terraform#34502
• Consider Explicit Error Diagnostic When UpgradeResourceState Response State Includes Unknown Value terraform#34503