Migration of null resource to terraform data (#2481)

Signed-off-by: Ilia Gogotchuri <ilia.gogotchuri0@gmail.com>

CHANGELOG.md

@@ -17,6 +17,7 @@ ENHANCEMENTS:
 * State encryption now supports using external programs as key providers. Additionally, the PBKDF2 key provider now supports chaining via the `chain` parameter. ([#2023](https://github.com/opentofu/opentofu/pull/2023))
 * The `element` function now accepts negative indices, which extends the existing "wrapping" model into the negative direction. In particular, choosing element `-1` selects the final element in the sequence. ([#2371](https://github.com/opentofu/opentofu/pull/2371))
 * `moved` now supports moving between different types ([#2370](https://github.com/opentofu/opentofu/pull/2370))
+* `moved` block can now be used to migrate from the `null_resource` to the `terraform_data` resource. ([#2481](https://github.com/opentofu/opentofu/pull/2481))
 
 BUG FIXES:
 

internal/builtin/providers/tf/provider.go

@@ -169,11 +169,14 @@ func (p *Provider) ImportResourceState(req providers.ImportResourceStateRequest)
 	panic("unimplemented - terraform_remote_state has no resources")
 }
 
+// MoveResourceState is called when the state loader encounters an instance state
+// that has been moved to a new type, and the state should be updated to reflect the change.
+// This is used to move the old state to the new schema.
 func (p *Provider) MoveResourceState(r providers.MoveResourceStateRequest) (resp providers.MoveResourceStateResponse) {
-	panic("unimplmented")
+	return moveDataStoreResourceState(r)
 }
 
-// ValidateResourceConfig is used to to validate the resource configuration values.
+// ValidateResourceConfig is used to validate the resource configuration values.
 func (p *Provider) ValidateResourceConfig(req providers.ValidateResourceConfigRequest) providers.ValidateResourceConfigResponse {
 	return validateDataStoreResourceConfig(req)
 }

internal/builtin/providers/tf/resource_data.go

@@ -56,6 +56,54 @@ func upgradeDataStoreResourceState(req providers.UpgradeResourceStateRequest) (r
 	return resp
 }
 
+// nullResourceSchema returns a schema for a null_resource with relevant attributes for type migration.
+func nullResourceSchema() providers.Schema {
+	return providers.Schema{
+		Block: &configschema.Block{
+			Attributes: map[string]*configschema.Attribute{
+				"triggers": {Type: cty.Map(cty.String), Optional: true},
+				"id":       {Type: cty.String, Computed: true},
+			},
+		},
+	}
+
+}
+
+func moveDataStoreResourceState(req providers.MoveResourceStateRequest) providers.MoveResourceStateResponse {
+	var resp providers.MoveResourceStateResponse
+	if req.SourceTypeName != "null_resource" || req.TargetTypeName != "terraform_data" {
+		resp.Diagnostics = resp.Diagnostics.Append(
+			fmt.Errorf("unsupported move: %s -> %s; only move from null_resource to terraform_data is supported",
+				req.SourceTypeName, req.TargetTypeName))
+		return resp
+	}
+	nullTy := nullResourceSchema().Block.ImpliedType()
+	oldState, err := ctyjson.Unmarshal(req.SourceStateJSON, nullTy)
+	if err != nil {
+		resp.Diagnostics = resp.Diagnostics.Append(err)
+		return resp
+	}
+	oldStateMap := oldState.AsValueMap()
+	newStateMap := map[string]cty.Value{}
+
+	if trigger, ok := oldStateMap["triggers"]; ok && !trigger.IsNull() {
+		newStateMap["triggers_replace"] = cty.ObjectVal(trigger.AsValueMap())
+	}
+	if id, ok := oldStateMap["id"]; ok && !id.IsNull() {
+		newStateMap["id"] = id
+	}
+
+	currentSchema := dataStoreResourceSchema()
+	newState, err := currentSchema.Block.CoerceValue(cty.ObjectVal(newStateMap))
+	if err != nil {
+		resp.Diagnostics = resp.Diagnostics.Append(err)
+		return resp
+	}
+	resp.TargetState = newState
+	resp.TargetPrivate = req.SourcePrivate
+	return resp
+}
+
 func readDataStoreResourceState(req providers.ReadResourceRequest) (resp providers.ReadResourceResponse) {
 	resp.NewState = req.PriorState
 	return resp

internal/builtin/providers/tf/resource_data_test.go

@@ -6,6 +6,7 @@
 package tf
 
 import (
+	"bytes"
 	"strings"
 	"testing"
 
@@ -82,6 +83,57 @@ func TestManagedDataUpgradeState(t *testing.T) {
 	}
 }
 
+func TestManagedDataMovedState(t *testing.T) {
+	nullSchema := nullResourceSchema()
+	nullTy := nullSchema.Block.ImpliedType()
+
+	state := cty.ObjectVal(map[string]cty.Value{
+		"triggers": cty.MapVal(map[string]cty.Value{
+			"examplekey": cty.StringVal("value"),
+		}),
+		"id": cty.StringVal("not-quite-unique"),
+	})
+
+	jsState, err := ctyjson.Marshal(state, nullTy)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// empty request should fail
+	req := providers.MoveResourceStateRequest{}
+
+	resp := moveDataStoreResourceState(req)
+	if !resp.Diagnostics.HasErrors() {
+		t.Fatalf("expected error, got %#v", resp)
+	}
+
+	// valid request
+	req = providers.MoveResourceStateRequest{
+		TargetTypeName:  "terraform_data",
+		SourceTypeName:  "null_resource",
+		SourcePrivate:   []byte("PRIVATE"),
+		SourceStateJSON: jsState,
+	}
+
+	resp = moveDataStoreResourceState(req)
+
+	expectedState := cty.ObjectVal(map[string]cty.Value{
+		"triggers_replace": cty.ObjectVal(map[string]cty.Value{
+			"examplekey": cty.StringVal("value"),
+		}),
+		"id":     cty.StringVal("not-quite-unique"),
+		"input":  cty.NullVal(cty.DynamicPseudoType),
+		"output": cty.NullVal(cty.DynamicPseudoType),
+	})
+	if !resp.TargetState.RawEquals(expectedState) {
+		t.Errorf("prior state was:\n%#v\nmoved state is:\n%#v\n", expectedState, resp.TargetState)
+	}
+
+	if !bytes.Equal(resp.TargetPrivate, req.SourcePrivate) {
+		t.Error("expected private data to be copied")
+	}
+
+}
 func TestManagedDataRead(t *testing.T) {
 	req := providers.ReadResourceRequest{
 		TypeName: "terraform_data",

website/docs/intro/whats-new.mdx

@@ -11,6 +11,7 @@ This page will run you through the most important changes in OpenTofu 1.10:
 
 - [New features](#new-features)
   - [New built-in functions](#new-built-in-functions)
+  - [Moved for different resource types](#moved-for-different-resource-types)
 - [Improvements to existing features](#improvements-to-existing-features)
   - [External programs as encryption key providers (experimental)](#external-programs-as-encryption-key-providers-experimental)
   - [Smaller improvements](#smaller-improvements)
@@ -28,6 +29,11 @@ New builtin provider functions added ([#2306](https://github.com/opentofu/opento
 - `provider::terraform::encode_tfvars` - Encode an object into a string with the same format as a TFVars file.
 - `provider::terraform::encode_expr` - Encode an arbitrary expression into a string with valid OpenTofu syntax.
 
+### Moved for different resource types
+
+- `moved` block can now be used to migrate between different types of resources ([docs](../language/modules/develop/refactoring.mdx#changing-a-resource-type)).
+- Builtin provider now supports migration from `null_resource` to `terraform_data` resource.
+
 ## Improvements to existing features
 
 ### External programs as encryption key providers (experimental)

website/docs/language/resources/tf-data.mdx

@@ -63,6 +63,7 @@ resource "terraform_data" "bootstrap" {
 }
 ```
 
+`moved` block can be used to migrate from the `null_resource` to the `terraform_data` resource. [Migration guide](https://search.opentofu.org/provider/hashicorp/null/latest/docs/guides/terraform-migration)
 
 ## Argument Reference