command/show (json): marshal the state snapshot included with the plan file (#21597)

* command/show: marshal the state snapshot from the planfile

The planfile contains a state snapshot with certain resources updated
(outputs and datasources). Previously `terraform show -json PLANFILE`
was using the current state instead of the state inside the plan as
intended.

This caused an issue when the state included a terraform_remote_state
datasource. The datasource's state gets refreshed - and therefore
upgraded to the current state version - during plan, but that won't
persist to state until apply.

* update comment to reflect new return

command/jsonplan/plan.go

@@ -91,12 +91,7 @@ func Marshal(
 	p *plans.Plan,
 	sf *statefile.File,
 	schemas *terraform.Schemas,
-	stateSchemas *terraform.Schemas,
 ) ([]byte, error) {
-	if stateSchemas == nil {
-		stateSchemas = schemas
-	}
-
 	output := newPlan()
 	output.TerraformVersion = version.String()
 
@@ -125,7 +120,7 @@ func Marshal(
 
 	// output.PriorState
 	if sf != nil && !sf.State.Empty() {
-		output.PriorState, err = jsonstate.Marshal(sf, stateSchemas)
+		output.PriorState, err = jsonstate.Marshal(sf, schemas)
 		if err != nil {
 			return nil, fmt.Errorf("error marshaling prior state: %s", err)
 		}

command/show.go

@@ -115,7 +115,7 @@ func (c *ShowCommand) Run(args []string) int {
 	// if that fails, try to read the cli argument as a path to a statefile
 	if len(args) > 0 {
 		path := args[0]
-		plan, planErr = getPlanFromPath(path)
+		plan, stateFile, planErr = getPlanFromPath(path)
 		if planErr != nil {
 			stateFile, stateErr = getStateFromPath(path)
 			if stateErr != nil {
@@ -129,9 +129,7 @@ func (c *ShowCommand) Run(args []string) int {
 				return 1
 			}
 		}
-	}
+	} else {
-
-	if stateFile == nil {
 		env := c.Workspace()
 		stateFile, stateErr = getStateFromEnv(b, env)
 		if err != nil {
@@ -143,29 +141,7 @@ func (c *ShowCommand) Run(args []string) int {
 	if plan != nil {
 		if jsonOutput == true {
 			config := ctx.Config()
-
+			jsonPlan, err := jsonplan.Marshal(config, plan, stateFile, schemas)
-			var err error
-			var jsonPlan []byte
-
-			// If there is no prior state, we have all the schemas needed.
-			if stateFile == nil {
-				jsonPlan, err = jsonplan.Marshal(config, plan, stateFile, schemas, nil)
-			} else {
-				// If there is state, we need the state-specific schemas, which
-				// may differ from the schemas loaded from the plan.
-				// This occurs if there is a data_source in the state that was
-				// removed from the configuration, because terraform core does
-				// not need to load the schema to remove a data source.
-				opReq.PlanFile = nil
-				ctx, _, ctxDiags := local.Context(opReq)
-				diags = diags.Append(ctxDiags)
-				if ctxDiags.HasErrors() {
-					c.showDiagnostics(diags)
-					return 1
-				}
-				stateSchemas := ctx.Schemas()
-				jsonPlan, err = jsonplan.Marshal(config, plan, stateFile, schemas, stateSchemas)
-			}
 
 			if err != nil {
 				c.Ui.Error(fmt.Sprintf("Failed to marshal plan to json: %s", err))
@@ -224,19 +200,21 @@ func (c *ShowCommand) Synopsis() string {
 	return "Inspect Terraform state or plan"
 }
 
-// getPlanFromPath returns a plan if the user-supplied path points to a planfile.
+// getPlanFromPath returns a plan and statefile if the user-supplied path points
-// If both plan and error are nil, the path is likely a directory.
+// to a planfile. If both plan and error are nil, the path is likely a
-// An error could suggest that the given path points to a statefile.
+// directory. An error could suggest that the given path points to a statefile.
-func getPlanFromPath(path string) (*plans.Plan, error) {
+func getPlanFromPath(path string) (*plans.Plan, *statefile.File, error) {
 	pr, err := planfile.Open(path)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	plan, err := pr.ReadPlan()
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
-	return plan, nil
+
+	stateFile, err := pr.ReadStateFile()
+	return plan, stateFile, nil
 }
 
 // getStateFromPath returns a statefile if the user-supplied path points to a statefile.

command/show_test.go

@@ -412,6 +412,11 @@ type plan struct {
 	PlannedValues   map[string]interface{} `json:"planned_values,omitempty"`
 	ResourceChanges []interface{}          `json:"resource_changes,omitempty"`
 	OutputChanges   map[string]interface{} `json:"output_changes,omitempty"`
-	PriorState      map[string]interface{} `json:"prior_state,omitempty"`
+	PriorState      priorState             `json:"prior_state,omitempty"`
 	Config          map[string]interface{} `json:"configuration,omitempty"`
 }
+
+type priorState struct {
+	FormatVersion string                 `json:"format_version,omitempty"`
+	Values        map[string]interface{} `json:"values,omitempty"`
+}

command/test-fixtures/show-json/basic-create/output.json

@@ -53,6 +53,18 @@
             ]
         }
     },
+    "prior_state": {
+        "format_version": "0.1",
+        "values": {
+            "outputs": {
+                "test": {
+                    "sensitive": false,
+                    "value": "bar"
+                }
+            },
+            "root_module": {}
+        }
+    },
     "resource_changes": [
         {
             "address": "test_instance.test[0]",

command/test-fixtures/show-json/basic-delete/output.json

@@ -82,8 +82,13 @@
     },
     "prior_state": {
         "format_version": "0.1",
-        "terraform_version": "0.12.0",
         "values": {
+            "outputs": {
+                "test": {
+                    "sensitive": false,
+                    "value": "bar"
+                }
+            },
             "root_module": {
                 "resources": [
                     {

command/test-fixtures/show-json/basic-update/output.json

@@ -64,8 +64,13 @@
     },
     "prior_state": {
         "format_version": "0.1",
-        "terraform_version": "0.12.0",
         "values": {
+            "outputs": {
+                "test": {
+                    "sensitive": false,
+                    "value": "bar"
+                }
+            },
             "root_module": {
                 "resources": [
                     {

command/test-fixtures/show-json/modules/output.json

@@ -69,6 +69,18 @@
             ]
         }
     },
+    "prior_state": {
+        "format_version": "0.1",
+        "values": {
+            "outputs": {
+                "test": {
+                    "sensitive": false,
+                    "value": "baz"
+                }
+            },
+            "root_module": {}
+        }
+    },
     "resource_changes": [
         {
             "address": "module.module_test_bar.test_instance.test",