states: object Private data is []byte, not cty.Value

We're going to allow the provider to encode whatever it wants in here, so
a provider can use whatever is most convenient for its implementation
language and to avoid some of the bugs we saw with the prior model where
the forced round-trip through JSON and back into interface{} would cause
some loss of fidelity, leading to bugs.

states/import.go

@@ -18,7 +18,7 @@ type ImportedObject struct {
 	// Private corresponds to the field of the same name on
 	// ResourceInstanceObject, where the provider can record private data that
 	// will be available for future operations.
-	Private cty.Value
+	Private []byte
 }
 
 // AsInstanceObject converts the receiving ImportedObject into a

states/instance_object.go

@@ -23,7 +23,7 @@ type ResourceInstanceObject struct {
 	// last created or updated. Terraform Core does not use this value in
 	// any way and it is not exposed anywhere in the user interface, so
 	// a provider can use it for retaining any necessary private state.
-	Private cty.Value
+	Private []byte
 
 	// Status represents the "readiness" of the object as of the last time
 	// it was updated.

states/instance_object_src.go

@@ -51,7 +51,7 @@ type ResourceInstanceObjectSrc struct {
 
 	// These fields all correspond to the fields of the same name on
 	// ResourceInstanceObject.
-	Private      cty.Value
+	Private      []byte
 	Status       ObjectStatus
 	Dependencies []addrs.Referenceable
 }

states/statefile/testdata/roundtrip/v3-grabbag.in.tfstate

@@ -38,7 +38,9 @@
                             "triggers.%": "1",
                             "triggers.index": "0"
                         },
-                        "meta": {},
+                        "meta": {
+                            "schema_version": "1"
+                        },
                         "tainted": false
                     },
                     "deposed": [],
@@ -80,7 +82,9 @@
                             "triggers.woot": "us-west-2",
                             "triggers.workspace": "default"
                         },
-                        "meta": {},
+                        "meta": {
+                            "foo": "bar"
+                        },
                         "tainted": false
                     },
                     "deposed": [],

states/statefile/testdata/roundtrip/v3-grabbag.out.tfstate

@@ -38,7 +38,7 @@
                     },
                     "depends_on": ["null_resource.baz"],
                     "index_key": 0,
-                    "schema_version": 0
+                    "schema_version": 1
                 },
                 {
                     "attributes_flat": {
@@ -72,7 +72,8 @@
                         "triggers.woot": "us-west-2",
                         "triggers.workspace": "default"
                     },
-                    "schema_version": 0
+                    "schema_version": 0,
+                    "private": "eyJmb28iOiJiYXIifQ=="
                 }
             ]
         },

states/statefile/version3_upgrade.go

@@ -224,12 +224,19 @@ func upgradeInstanceObjectV3ToV4(rsOld *resourceStateV2, isOld *instanceStateV2,
 	var schemaVersion uint64
 	migratedSchemaVersion := false
 	if raw, exists := isOld.Meta["schema_version"]; exists {
-		if rawStr, ok := raw.(string); ok {
-			v, err := strconv.ParseUint(rawStr, 10, 64)
+		switch tv := raw.(type) {
+		case string:
+			v, err := strconv.ParseUint(tv, 10, 64)
 			if err == nil {
 				schemaVersion = v
 				migratedSchemaVersion = true
 			}
+		case int:
+			schemaVersion = uint64(tv)
+			migratedSchemaVersion = true
+		case float64:
+			schemaVersion = uint64(tv)
+			migratedSchemaVersion = true
 		}
 	}
 

states/statefile/version4.go

@@ -7,7 +7,6 @@ import (
 	"sort"
 
 	version "github.com/hashicorp/go-version"
-	"github.com/zclconf/go-cty/cty"
 	ctyjson "github.com/zclconf/go-cty/cty/json"
 
 	"github.com/hashicorp/terraform/addrs"
@@ -178,28 +177,7 @@ func prepareStateV4(sV4 *stateV4) (*File, tfdiags.Diagnostics) {
 			}
 
 			if raw := isV4.PrivateRaw; len(raw) > 0 {
-				// Private metadata
-				ty, err := ctyjson.ImpliedType(raw)
-				if err != nil {
-					diags = diags.Append(tfdiags.Sourceless(
-						tfdiags.Error,
-						"Invalid resource instance metadata in state",
-						fmt.Sprintf("Instance %s has invalid private metadata: %s.", instAddr.Absolute(moduleAddr), err),
-					))
-					continue
-				}
-
-				val, err := ctyjson.Unmarshal(raw, ty)
-				if err != nil {
-					diags = diags.Append(tfdiags.Sourceless(
-						tfdiags.Error,
-						"Invalid resource instance metadata in state",
-						fmt.Sprintf("Instance %s has invalid private metadata: %s.", instAddr.Absolute(moduleAddr), err),
-					))
-					continue
-				}
-
-				obj.Private = val
+				obj.Private = raw
 			}
 
 			{
@@ -475,17 +453,9 @@ func appendInstanceObjectStateV4(rs *states.Resource, is *states.ResourceInstanc
 		))
 	}
 
-	var privateRaw json.RawMessage
-	if obj.Private != cty.NilVal {
-		var err error
-		privateRaw, err = ctyjson.Marshal(obj.Private, obj.Private.Type())
-		if err != nil {
-			diags = diags.Append(tfdiags.Sourceless(
-				tfdiags.Error,
-				"Failed to serialize resource instance in state",
-				fmt.Sprintf("Failed to serialize instance %s private metadata: %s.", rs.Addr.Instance(key), err),
-			))
-		}
+	var privateRaw []byte
+	if len(obj.Private) > 0 {
+		privateRaw = obj.Private
 	}
 
 	deps := make([]string, len(obj.Dependencies))
@@ -565,7 +535,7 @@ type instanceObjectStateV4 struct {
 	AttributesRaw  json.RawMessage   `json:"attributes,omitempty"`
 	AttributesFlat map[string]string `json:"attributes_flat,omitempty"`
 
-	PrivateRaw json.RawMessage `json:"private,omitempty"`
+	PrivateRaw []byte `json:"private,omitempty"`
 
 	Dependencies []string `json:"depends_on,omitempty"`
 }