PSS: Update how commands access backends, so both backend and state_store configuration can be used (#37569)

* Add a generic method for loading an operations backend in non-init commands

* Refactor commands to use new prepareBackend method: group 1

* Refactor commands to use new prepareBackend method: group 2, where config parsing needs to be explicitly added

* Refactor commands to use new prepareBackend method: group 3, where we can use already parsed config

* Additional, more nested, places where logic for accessing backends needs to be refactored

* Remove duplicated comment

* Add test coverage of `(m *Meta) prepareBackend()`

* Add TODO related to using plans for backend/state_store config in apply commands

* Add `testStateStoreMockWithChunkNegotiation` test helper

* Add assertions to tests about the backend (remote-state, local, etc) in use within operations backend

* Stop prepareBackend taking locks as argument

* Code comment in prepareBackend

* Replace c.Meta.prepareBackend with c.prepareBackend

* Change `c.Meta.loadSingleModule` to `c.loadSingleModule`

* Rename (Meta).prepareBackend to  (Meta).backend, update godoc comment to make relationship to (Meta).Backend more obvious.

* Revert change from config.Module to config.Root.Module

* Update `(m *Meta) backend` method to parse config itself, and also to adhere to calling code's viewtype instructions

* Update all tests and calling code following previous commit

* Change how an operations backend is obtained by autocomplete code

* Update autocomplete to return nil if no workspace names are returned from the backend

* Add test coverage for autocompleting workspace names when using a pluggable state store

* Fix output command: pass view type data to new `backend` method

* Fix in plan command: pass correct view type to `backend` method

* Fix `providers schema` command to use correct viewtype when preparing a backend

internal/command/apply.go

@@ -219,19 +219,15 @@ func (c *ApplyCommand) PrepareBackend(planFile *planfile.WrappedPlanFile, args *
 			))
 			return nil, diags
 		}
+		// TODO: Update BackendForLocalPlan to use state storage, and plan to be able to contain State Store config details
 		be, beDiags = c.BackendForLocalPlan(plan.Backend)
 	} else {
-		// Both new plans and saved cloud plans load their backend from config.
-		backendConfig, configDiags := c.loadBackendConfig(".")
-		diags = diags.Append(configDiags)
-		if configDiags.HasErrors() {
-			return nil, diags
-		}
 
-		be, beDiags = c.Backend(&BackendOpts{
-			BackendConfig: backendConfig,
-			ViewType:      viewType,
-		})
+		// Load the backend
+		//
+		// Note: Both new plans and saved cloud plans load their backend from config,
+		// hence the config parsing in the method below.
+		be, beDiags = c.backend(".", viewType)
 	}
 
 	diags = diags.Append(beDiags)

internal/command/autocomplete.go

@@ -4,6 +4,7 @@
 package command
 
 import (
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/posener/complete"
 )
 
@@ -48,19 +49,18 @@ func (m *Meta) completePredictWorkspaceName() complete.Predictor {
 			return nil
 		}
 
-		backendConfig, diags := m.loadBackendConfig(configPath)
-		if diags.HasErrors() {
-			return nil
-		}
-
-		b, diags := m.Backend(&BackendOpts{
-			BackendConfig: backendConfig,
-		})
+		b, diags := m.backend(configPath, arguments.ViewHuman)
 		if diags.HasErrors() {
 			return nil
 		}
 
 		names, _ := b.Workspaces()
+		if len(names) == 0 {
+			// Presence of the "default" isn't always guaranteed
+			// Backends will report it as always existing, pluggable
+			// state stores will only do so if it _actually_ exists.
+			return nil
+		}
 		return names
 	})
 }

internal/command/autocomplete_test.go

@@ -4,37 +4,124 @@
 package command
 
 import (
-	"io/ioutil"
-	"os"
 	"reflect"
 	"testing"
 
 	"github.com/hashicorp/cli"
+	"github.com/hashicorp/terraform/internal/addrs"
+	"github.com/hashicorp/terraform/internal/command/workdir"
+	"github.com/hashicorp/terraform/internal/providers"
 	"github.com/posener/complete"
 )
 
 func TestMetaCompletePredictWorkspaceName(t *testing.T) {
-	// Create a temporary working directory that is empty
-	td := t.TempDir()
-	os.MkdirAll(td, 0755)
-	t.Chdir(td)
 
-	// make sure a vars file doesn't interfere
-	err := ioutil.WriteFile(DefaultVarsFilename, nil, 0644)
-	if err != nil {
-		t.Fatal(err)
-	}
+	t.Run("test autocompletion using the local backend", func(t *testing.T) {
+		// Create a temporary working directory that is empty
+		td := t.TempDir()
+		t.Chdir(td)
 
-	ui := new(cli.MockUi)
-	meta := &Meta{Ui: ui}
+		ui := new(cli.MockUi)
+		meta := &Meta{Ui: ui}
 
-	predictor := meta.completePredictWorkspaceName()
+		predictor := meta.completePredictWorkspaceName()
 
-	got := predictor.Predict(complete.Args{
-		Last: "",
+		got := predictor.Predict(complete.Args{
+			Last: "",
+		})
+		want := []string{"default"}
+		if !reflect.DeepEqual(got, want) {
+			t.Errorf("wrong result\ngot:  %#v\nwant: %#v", got, want)
+		}
+	})
+
+	t.Run("test autocompletion using a state store", func(t *testing.T) {
+		// Create a temporary working directory with state_store config
+		td := t.TempDir()
+		testCopyDir(t, testFixturePath("state-store-unchanged"), td)
+		t.Chdir(td)
+
+		// Set up pluggable state store provider mock
+		mockProvider := mockPluggableStateStorageProvider()
+		// Mock the existence of workspaces
+		mockProvider.MockStates = map[string]interface{}{
+			"default": true,
+			"foobar":  true,
+		}
+		mockProviderAddress := addrs.NewDefaultProvider("test")
+		providerSource, close := newMockProviderSource(t, map[string][]string{
+			"hashicorp/test": {"1.0.0"},
+		})
+		defer close()
+
+		ui := new(cli.MockUi)
+		view, _ := testView(t)
+		wd := workdir.NewDir(".")
+		wd.OverrideOriginalWorkingDir(td)
+		meta := Meta{
+			WorkingDir:                wd, // Use the test's temp dir
+			Ui:                        ui,
+			View:                      view,
+			AllowExperimentalFeatures: true,
+			testingOverrides: &testingOverrides{
+				Providers: map[addrs.Provider]providers.Factory{
+					mockProviderAddress: providers.FactoryFixed(mockProvider),
+				},
+			},
+			ProviderSource: providerSource,
+		}
+
+		predictor := meta.completePredictWorkspaceName()
+
+		got := predictor.Predict(complete.Args{
+			Last: "",
+		})
+		want := []string{"default", "foobar"}
+		if !reflect.DeepEqual(got, want) {
+			t.Errorf("wrong result\ngot:  %#v\nwant: %#v", got, want)
+		}
+	})
+
+	t.Run("test autocompletion using a state store containing no workspaces", func(t *testing.T) {
+		// Create a temporary working directory with state_store config
+		td := t.TempDir()
+		testCopyDir(t, testFixturePath("state-store-unchanged"), td)
+		t.Chdir(td)
+
+		// Set up pluggable state store provider mock
+		mockProvider := mockPluggableStateStorageProvider()
+		// No workspaces exist in the mock
+		mockProvider.MockStates = map[string]interface{}{}
+		mockProviderAddress := addrs.NewDefaultProvider("test")
+		providerSource, close := newMockProviderSource(t, map[string][]string{
+			"hashicorp/test": {"1.0.0"},
+		})
+		defer close()
+
+		ui := new(cli.MockUi)
+		view, _ := testView(t)
+		wd := workdir.NewDir(".")
+		wd.OverrideOriginalWorkingDir(td)
+		meta := Meta{
+			WorkingDir:                wd, // Use the test's temp dir
+			Ui:                        ui,
+			View:                      view,
+			AllowExperimentalFeatures: true,
+			testingOverrides: &testingOverrides{
+				Providers: map[addrs.Provider]providers.Factory{
+					mockProviderAddress: providers.FactoryFixed(mockProvider),
+				},
+			},
+			ProviderSource: providerSource,
+		}
+
+		predictor := meta.completePredictWorkspaceName()
+
+		got := predictor.Predict(complete.Args{
+			Last: "",
+		})
+		if got != nil {
+			t.Errorf("wrong result\ngot:  %#v\nwant: %#v", got, nil)
+		}
 	})
-	want := []string{"default"}
-	if !reflect.DeepEqual(got, want) {
-		t.Errorf("wrong result\ngot:  %#v\nwant: %#v", got, want)
-	}
 }

internal/command/console.go

@@ -53,17 +53,8 @@ func (c *ConsoleCommand) Run(args []string) int {
 
 	var diags tfdiags.Diagnostics
 
-	backendConfig, backendDiags := c.loadBackendConfig(configPath)
-	diags = diags.Append(backendDiags)
-	if diags.HasErrors() {
-		c.showDiagnostics(diags)
-		return 1
-	}
-
 	// Load the backend
-	b, backendDiags := c.Backend(&BackendOpts{
-		BackendConfig: backendConfig,
-	})
+	b, backendDiags := c.backend(configPath, arguments.ViewHuman)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/graph.go

@@ -68,17 +68,8 @@ func (c *GraphCommand) Run(args []string) int {
 
 	var diags tfdiags.Diagnostics
 
-	backendConfig, backendDiags := c.loadBackendConfig(configPath)
-	diags = diags.Append(backendDiags)
-	if diags.HasErrors() {
-		c.showDiagnostics(diags)
-		return 1
-	}
-
 	// Load the backend
-	b, backendDiags := c.Backend(&BackendOpts{
-		BackendConfig: backendConfig,
-	})
+	b, backendDiags := c.backend(".", arguments.ViewHuman)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/import.go

@@ -164,9 +164,7 @@ func (c *ImportCommand) Run(args []string) int {
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(&BackendOpts{
-		BackendConfig: config.Module.Backend,
-	})
+	b, backendDiags := c.backend(".", arguments.ViewHuman)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/meta_backend.go

@@ -1580,6 +1580,82 @@ func (m *Meta) updateSavedBackendHash(cHash int, sMgr *clistate.LocalState) tfdi
 	return diags
 }
 
+// backend returns an operations backend that may use a backend, cloud, or state_store block for state storage.
+// Based on the supplied config, it prepares arguments to pass into (Meta).Backend, which returns the operations backend.
+//
+// This method should be used in NON-init operations only; it's incapable of processing new init command CLI flags used
+// for partial configuration, however it will use the backend state file to use partial configuration from a previous
+// init command.
+func (m *Meta) backend(configPath string, viewType arguments.ViewType) (backendrun.OperationsBackend, tfdiags.Diagnostics) {
+	var diags tfdiags.Diagnostics
+
+	if configPath == "" {
+		configPath = "."
+	}
+
+	// Only return error diagnostics at this point. Any warnings will be caught
+	// again later and duplicated in the output.
+	root, mDiags := m.loadSingleModule(configPath)
+	if mDiags.HasErrors() {
+		diags = diags.Append(mDiags)
+		return nil, diags
+	}
+
+	var opts *BackendOpts
+	switch {
+	case root.Backend != nil:
+		opts = &BackendOpts{
+			BackendConfig: root.Backend,
+			ViewType:      viewType,
+		}
+	case root.CloudConfig != nil:
+		backendConfig := root.CloudConfig.ToBackendConfig()
+		opts = &BackendOpts{
+			BackendConfig: &backendConfig,
+			ViewType:      viewType,
+		}
+	case root.StateStore != nil:
+		// In addition to config, use of a state_store requires
+		// provider factory and provider locks data
+		locks, lDiags := m.lockedDependencies()
+		diags = diags.Append(lDiags)
+		if lDiags.HasErrors() {
+			return nil, diags
+		}
+
+		factory, fDiags := m.GetStateStoreProviderFactory(root.StateStore, locks)
+		diags = diags.Append(fDiags)
+		if fDiags.HasErrors() {
+			return nil, diags
+		}
+
+		opts = &BackendOpts{
+			StateStoreConfig: root.StateStore,
+			ProviderFactory:  factory,
+			Locks:            locks,
+			ViewType:         viewType,
+		}
+	default:
+		// there is no config; defaults to local state storage
+		opts = &BackendOpts{
+			ViewType: viewType,
+		}
+	}
+
+	// This method should not be used for init commands,
+	// so we always set this value as false.
+	opts.Init = false
+
+	// Load the backend
+	be, beDiags := m.Backend(opts)
+	diags = diags.Append(beDiags)
+	if beDiags.HasErrors() {
+		return nil, diags
+	}
+
+	return be, diags
+}
+
 //-------------------------------------------------------------------
 // State Store Config Scenarios
 // The functions below cover handling all the various scenarios that

internal/command/meta_backend_test.go

@@ -23,6 +23,7 @@ import (
 	"github.com/hashicorp/terraform/internal/addrs"
 	"github.com/hashicorp/terraform/internal/backend"
 	"github.com/hashicorp/terraform/internal/cloud"
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/hashicorp/terraform/internal/command/clistate"
 	"github.com/hashicorp/terraform/internal/command/workdir"
 	"github.com/hashicorp/terraform/internal/configs"
@@ -2962,6 +2963,126 @@ func Test_getStateStorageProviderVersion(t *testing.T) {
 	})
 }
 
+func TestMetaBackend_prepareBackend(t *testing.T) {
+
+	t.Run("it returns a cloud backend from cloud backend config", func(t *testing.T) {
+		// Create a temporary working directory with cloud configuration in
+		td := t.TempDir()
+		testCopyDir(t, testFixturePath("cloud-config"), td)
+		t.Chdir(td)
+
+		m := testMetaBackend(t, nil)
+
+		// We cannot initialize a cloud backend so we instead check
+		// the init error is referencing HCP Terraform
+		_, bDiags := m.backend(td, arguments.ViewHuman)
+		if !bDiags.HasErrors() {
+			t.Fatal("expected error but got none")
+		}
+		wantErr := "HCP Terraform or Terraform Enterprise initialization required: please run \"terraform init\""
+		if !strings.Contains(bDiags.Err().Error(), wantErr) {
+			t.Fatalf("expected error to contain %q, but got: %q",
+				wantErr,
+				bDiags.Err())
+		}
+	})
+
+	t.Run("it returns a backend from backend config", func(t *testing.T) {
+		// Create a temporary working directory with backend configuration in
+		td := t.TempDir()
+		testCopyDir(t, testFixturePath("backend-unchanged"), td)
+		t.Chdir(td)
+
+		m := testMetaBackend(t, nil)
+
+		b, bDiags := m.backend(td, arguments.ViewHuman)
+		if bDiags.HasErrors() {
+			t.Fatal("unexpected error: ", bDiags.Err())
+		}
+
+		if _, ok := b.(*local.Local); !ok {
+			t.Fatal("expected returned operations backend to be a Local backend")
+		}
+		// Check the type of backend inside the Local via schema
+		// In this case a `local` backend should have been returned by default.
+		//
+		// Look for the path attribute.
+		schema := b.ConfigSchema()
+		if _, ok := schema.Attributes["path"]; !ok {
+			t.Fatalf("expected the operations backend to report the schema of a local backend, but got something unexpected: %#v", schema)
+		}
+	})
+
+	t.Run("it returns a local backend when there is empty configuration", func(t *testing.T) {
+		td := t.TempDir()
+		testCopyDir(t, testFixturePath("empty"), td)
+		t.Chdir(td)
+
+		m := testMetaBackend(t, nil)
+		b, bDiags := m.backend(td, arguments.ViewHuman)
+		if bDiags.HasErrors() {
+			t.Fatal("unexpected error: ", bDiags.Err())
+		}
+
+		if _, ok := b.(*local.Local); !ok {
+			t.Fatal("expected returned operations backend to be a Local backend")
+		}
+		// Check the type of backend inside the Local via schema
+		// In this case a `local` backend should have been returned by default.
+		//
+		// Look for the path attribute.
+		schema := b.ConfigSchema()
+		if _, ok := schema.Attributes["path"]; !ok {
+			t.Fatalf("expected the operations backend to report the schema of a local backend, but got something unexpected: %#v", schema)
+		}
+	})
+
+	t.Run("it returns a state_store from state_store config", func(t *testing.T) {
+		// Create a temporary working directory with backend configuration in
+		td := t.TempDir()
+		testCopyDir(t, testFixturePath("state-store-unchanged"), td)
+		t.Chdir(td)
+
+		m := testMetaBackend(t, nil)
+		m.AllowExperimentalFeatures = true
+		mock := testStateStoreMockWithChunkNegotiation(t, 12345) // chunk size needs to be set, value is arbitrary
+		m.testingOverrides = &testingOverrides{
+			Providers: map[addrs.Provider]providers.Factory{
+				addrs.NewDefaultProvider("test"): providers.FactoryFixed(mock),
+			},
+		}
+
+		// Prepare appropriate locks; config uses a hashicorp/test provider @ v1.2.3
+		locks := depsfile.NewLocks()
+		providerAddr := addrs.MustParseProviderSourceString("registry.terraform.io/hashicorp/test")
+		constraint, err := providerreqs.ParseVersionConstraints(">1.0.0")
+		if err != nil {
+			t.Fatalf("test setup failed when making constraint: %s", err)
+		}
+		locks.SetProvider(
+			providerAddr,
+			versions.MustParseVersion("1.2.3"),
+			constraint,
+			[]providerreqs.Hash{""},
+		)
+
+		b, bDiags := m.backend(td, arguments.ViewHuman)
+		if bDiags.HasErrors() {
+			t.Fatalf("unexpected error: %s", bDiags.Err())
+		}
+
+		if _, ok := b.(*local.Local); !ok {
+			t.Fatal("expected returned operations backend to be a Local backend")
+		}
+		// Check the state_store inside the Local via schema
+		// Look for the mock state_store's attribute called `value`.
+		schema := b.ConfigSchema()
+		if _, ok := schema.Attributes["value"]; !ok {
+			t.Fatalf("expected the operations backend to report the schema of the state_store, but got something unexpected: %#v", schema)
+		}
+	})
+}
+
 func testMetaBackend(t *testing.T, args []string) *Meta {
 	var m Meta
 	m.Ui = new(cli.MockUi)
@@ -3011,6 +3132,21 @@ func testStateStoreMock(t *testing.T) *testing_provider.MockProvider {
 	}
 }
 
+// testStateStoreMockWithChunkNegotiation is just like testStateStoreMock but the returned mock is set up so it'll be configured
+// without this error: `Failed to negotiate acceptable chunk size`
+//
+// This is meant to be a convenience method when a test is definitely not testing anything related to state store configuration.
+func testStateStoreMockWithChunkNegotiation(t *testing.T, chunkSize int64) *testing_provider.MockProvider {
+	t.Helper()
+	mock := testStateStoreMock(t)
+	mock.ConfigureStateStoreResponse = &providers.ConfigureStateStoreResponse{
+		Capabilities: providers.StateStoreServerCapabilities{
+			ChunkSize: chunkSize,
+		},
+	}
+	return mock
+}
+
 func configBodyForTest(t *testing.T, config string) hcl.Body {
 	t.Helper()
 	f, diags := hclsyntax.ParseConfig([]byte(config), "", hcl.Pos{Line: 1, Column: 1})

internal/command/output.go

@@ -35,7 +35,7 @@ func (c *OutputCommand) Run(rawArgs []string) int {
 	view := views.NewOutput(args.ViewType, c.View)
 
 	// Fetch data from state
-	outputs, diags := c.Outputs(args.StatePath)
+	outputs, diags := c.Outputs(args.StatePath, args.ViewType)
 	if diags.HasErrors() {
 		view.Diagnostics(diags)
 		return 1
@@ -54,7 +54,7 @@ func (c *OutputCommand) Run(rawArgs []string) int {
 	return 0
 }
 
-func (c *OutputCommand) Outputs(statePath string) (map[string]*states.OutputValue, tfdiags.Diagnostics) {
+func (c *OutputCommand) Outputs(statePath string, view arguments.ViewType) (map[string]*states.OutputValue, tfdiags.Diagnostics) {
 	var diags tfdiags.Diagnostics
 
 	// Allow state path override
@@ -63,9 +63,9 @@ func (c *OutputCommand) Outputs(statePath string) (map[string]*states.OutputValu
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(nil)
+	b, backendDiags := c.backend(".", view)
 	diags = diags.Append(backendDiags)
-	if diags.HasErrors() {
+	if backendDiags.HasErrors() {
 		return nil, diags
 	}
 

internal/command/plan.go

@@ -124,18 +124,9 @@ func (c *PlanCommand) PrepareBackend(args *arguments.State, viewType arguments.V
 	// difficult but would make their use easier to understand.
 	c.Meta.applyStateArguments(args)
 
-	backendConfig, diags := c.loadBackendConfig(".")
-	if diags.HasErrors() {
-		return nil, diags
-	}
-
 	// Load the backend
-	be, beDiags := c.Backend(&BackendOpts{
-		BackendConfig: backendConfig,
-		ViewType:      viewType,
-	})
-	diags = diags.Append(beDiags)
-	if beDiags.HasErrors() {
+	be, diags := c.backend(".", viewType)
+	if diags.HasErrors() {
 		return nil, diags
 	}
 

internal/command/providers.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/xlab/treeprint"
 
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/hashicorp/terraform/internal/configs"
 	"github.com/hashicorp/terraform/internal/getproviders"
 	"github.com/hashicorp/terraform/internal/tfdiags"
@@ -81,9 +82,7 @@ func (c *ProvidersCommand) Run(args []string) int {
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(&BackendOpts{
-		BackendConfig: config.Module.Backend,
-	})
+	b, backendDiags := c.backend(".", arguments.ViewHuman)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/providers_schema.go

@@ -45,6 +45,7 @@ func (c *ProvidersSchemaCommand) Run(args []string) int {
 		cmdFlags.Usage()
 		return 1
 	}
+	viewType := arguments.ViewJSON // See above; enforced use of JSON output
 
 	// Check for user-supplied plugin path
 	var err error
@@ -56,7 +57,7 @@ func (c *ProvidersSchemaCommand) Run(args []string) int {
 	var diags tfdiags.Diagnostics
 
 	// Load the backend
-	b, backendDiags := c.Backend(nil)
+	b, backendDiags := c.backend(".", viewType)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/query.go

@@ -154,21 +154,8 @@ func (c *QueryCommand) Run(rawArgs []string) int {
 }
 
 func (c *QueryCommand) PrepareBackend(args *arguments.State, viewType arguments.ViewType) (backendrun.OperationsBackend, tfdiags.Diagnostics) {
-	backendConfig, diags := c.loadBackendConfig(".")
-	if diags.HasErrors() {
-		return nil, diags
-	}
-
 	// Load the backend
-	be, beDiags := c.Backend(&BackendOpts{
-		BackendConfig: backendConfig,
-		ViewType:      viewType,
-	})
-	diags = diags.Append(beDiags)
-	if beDiags.HasErrors() {
-		return nil, diags
-	}
-
+	be, diags := c.backend(".", viewType)
 	return be, diags
 }
 

internal/command/refresh.go

@@ -117,18 +117,9 @@ func (c *RefreshCommand) PrepareBackend(args *arguments.State, viewType argument
 	// difficult but would make their use easier to understand.
 	c.Meta.applyStateArguments(args)
 
-	backendConfig, diags := c.loadBackendConfig(".")
-	if diags.HasErrors() {
-		return nil, diags
-	}
-
 	// Load the backend
-	be, beDiags := c.Backend(&BackendOpts{
-		BackendConfig: backendConfig,
-		ViewType:      viewType,
-	})
-	diags = diags.Append(beDiags)
-	if beDiags.HasErrors() {
+	be, diags := c.backend(".", viewType)
+	if diags.HasErrors() {
 		return nil, diags
 	}
 

internal/command/show.go

@@ -150,7 +150,7 @@ func (c *ShowCommand) showFromLatestStateSnapshot() (*statefile.File, tfdiags.Di
 	var diags tfdiags.Diagnostics
 
 	// Load the backend
-	b, backendDiags := c.Backend(nil)
+	b, backendDiags := c.backend(".", c.viewType)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		return nil, diags
@@ -278,9 +278,9 @@ func (c *ShowCommand) getPlanFromPath(path string) (*plans.Plan, *cloudplan.Remo
 
 func (c *ShowCommand) getDataFromCloudPlan(plan *cloudplan.SavedPlanBookmark, redacted bool) (*cloudplan.RemotePlanJSON, error) {
 	// Set up the backend
-	b, backendDiags := c.Backend(nil)
-	if backendDiags.HasErrors() {
-		return nil, errUnusable(backendDiags.Err(), "cloud plan")
+	b, diags := c.backend(".", c.viewType)
+	if diags.HasErrors() {
+		return nil, errUnusable(diags.Err(), "cloud plan")
 	}
 	// Cloud plans only work if we're cloud.
 	cl, ok := b.(*cloud.Cloud)

internal/command/state_identities.go

@@ -10,8 +10,8 @@ import (
 
 	"github.com/hashicorp/cli"
 	"github.com/hashicorp/terraform/internal/addrs"
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/hashicorp/terraform/internal/states"
-	"github.com/hashicorp/terraform/internal/tfdiags"
 )
 
 // StateIdentitiesCommand is a Command implementation that lists the resource identities
@@ -41,15 +41,16 @@ func (c *StateIdentitiesCommand) Run(args []string) int {
 		cmdFlags.Usage()
 		return 1
 	}
+	view := arguments.ViewJSON // See above
 
 	if statePath != "" {
 		c.Meta.statePath = statePath
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(nil)
-	if backendDiags.HasErrors() {
-		c.showDiagnostics(backendDiags)
+	b, diags := c.backend(".", view)
+	if diags.HasErrors() {
+		c.showDiagnostics(diags)
 		return 1
 	}
 
@@ -79,7 +80,6 @@ func (c *StateIdentitiesCommand) Run(args []string) int {
 	}
 
 	var addrs []addrs.AbsResourceInstance
-	var diags tfdiags.Diagnostics
 	if len(args) == 0 {
 		addrs, diags = c.lookupAllResourceInstanceAddrs(state)
 	} else {

internal/command/state_list.go

@@ -9,8 +9,8 @@ import (
 
 	"github.com/hashicorp/cli"
 	"github.com/hashicorp/terraform/internal/addrs"
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/hashicorp/terraform/internal/states"
-	"github.com/hashicorp/terraform/internal/tfdiags"
 )
 
 // StateListCommand is a Command implementation that lists the resources
@@ -37,9 +37,9 @@ func (c *StateListCommand) Run(args []string) int {
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(nil)
-	if backendDiags.HasErrors() {
-		c.showDiagnostics(backendDiags)
+	b, diags := c.backend(".", arguments.ViewHuman)
+	if diags.HasErrors() {
+		c.showDiagnostics(diags)
 		return 1
 	}
 
@@ -69,7 +69,6 @@ func (c *StateListCommand) Run(args []string) int {
 	}
 
 	var addrs []addrs.AbsResourceInstance
-	var diags tfdiags.Diagnostics
 	if len(args) == 0 {
 		addrs, diags = c.lookupAllResourceInstanceAddrs(state)
 	} else {

internal/command/state_meta.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/hashicorp/terraform/internal/addrs"
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/hashicorp/terraform/internal/states"
 	"github.com/hashicorp/terraform/internal/states/statemgr"
 	"github.com/hashicorp/terraform/internal/tfdiags"
@@ -25,7 +26,7 @@ type StateMeta struct {
 // the backend, but changes the way that backups are done. This configures
 // backups to be timestamped rather than just the original state path plus a
 // backup path.
-func (c *StateMeta) State() (statemgr.Full, error) {
+func (c *StateMeta) State(view arguments.ViewType) (statemgr.Full, error) {
 	var realState statemgr.Full
 	backupPath := c.backupPath
 	stateOutPath := c.statePath
@@ -34,10 +35,11 @@ func (c *StateMeta) State() (statemgr.Full, error) {
 	if c.statePath != "" {
 		realState = statemgr.NewFilesystem(c.statePath)
 	} else {
+
 		// Load the backend
-		b, backendDiags := c.Backend(nil)
-		if backendDiags.HasErrors() {
-			return nil, backendDiags.Err()
+		b, diags := c.backend(".", view)
+		if diags.HasErrors() {
+			return nil, diags.Err()
 		}
 
 		workspace, err := c.Workspace()

internal/command/state_mv.go

@@ -92,7 +92,8 @@ func (c *StateMvCommand) Run(args []string) int {
 	}
 
 	// Read the from state
-	stateFromMgr, err := c.State()
+	view := arguments.ViewHuman
+	stateFromMgr, err := c.State(view)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf(errStateLoadingState, err))
 		return 1
@@ -130,7 +131,7 @@ func (c *StateMvCommand) Run(args []string) int {
 		c.statePath = statePathOut
 		c.backupPath = backupPathOut
 
-		stateToMgr, err = c.State()
+		stateToMgr, err = c.State(view)
 		if err != nil {
 			c.Ui.Error(fmt.Sprintf(errStateLoadingState, err))
 			return 1
@@ -391,7 +392,8 @@ func (c *StateMvCommand) Run(args []string) int {
 		return 0 // This is as far as we go in dry-run mode
 	}
 
-	b, backendDiags := c.Backend(nil)
+	// Load the backend
+	b, backendDiags := c.backend(".", view)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/state_pull.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/hashicorp/terraform/internal/states/statefile"
 	"github.com/hashicorp/terraform/internal/states/statemgr"
 )
@@ -33,9 +34,10 @@ func (c *StatePullCommand) Run(args []string) int {
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(nil)
-	if backendDiags.HasErrors() {
-		c.showDiagnostics(backendDiags)
+	view := arguments.ViewHuman
+	b, diags := c.backend(".", view)
+	if diags.HasErrors() {
+		c.showDiagnostics(diags)
 		return 1
 	}
 

internal/command/state_push.go

@@ -16,7 +16,6 @@ import (
 	"github.com/hashicorp/terraform/internal/states/statefile"
 	"github.com/hashicorp/terraform/internal/states/statemgr"
 	"github.com/hashicorp/terraform/internal/terraform"
-	"github.com/hashicorp/terraform/internal/tfdiags"
 )
 
 // StatePushCommand is a Command implementation that allows
@@ -77,9 +76,10 @@ func (c *StatePushCommand) Run(args []string) int {
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(nil)
-	if backendDiags.HasErrors() {
-		c.showDiagnostics(backendDiags)
+	view := arguments.ViewHuman
+	b, diags := c.backend(".", view)
+	if diags.HasErrors() {
+		c.showDiagnostics(diags)
 		return 1
 	}
 
@@ -135,7 +135,6 @@ func (c *StatePushCommand) Run(args []string) int {
 
 	// Get schemas, if possible, before writing state
 	var schemas *terraform.Schemas
-	var diags tfdiags.Diagnostics
 	if isCloudMode(b) {
 		schemas, diags = c.MaybeGetSchemas(srcStateFile.State, nil)
 	}

internal/command/state_replace_provider.go

@@ -76,7 +76,8 @@ func (c *StateReplaceProviderCommand) Run(args []string) int {
 	}
 
 	// Initialize the state manager as configured
-	stateMgr, err := c.State()
+	view := arguments.ViewHuman
+	stateMgr, err := c.State(view)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf(errStateLoadingState, err))
 		return 1
@@ -164,7 +165,8 @@ func (c *StateReplaceProviderCommand) Run(args []string) int {
 		resource.ProviderConfig.Provider = to
 	}
 
-	b, backendDiags := c.Backend(nil)
+	// Load the backend
+	b, backendDiags := c.backend(".", view)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/state_rm.go

@@ -48,7 +48,8 @@ func (c *StateRmCommand) Run(args []string) int {
 	}
 
 	// Get the state
-	stateMgr, err := c.State()
+	view := arguments.ViewHuman
+	stateMgr, err := c.State(view)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf(errStateLoadingState, err))
 		return 1
@@ -115,7 +116,8 @@ func (c *StateRmCommand) Run(args []string) int {
 		return 0 // This is as far as we go in dry-run mode
 	}
 
-	b, backendDiags := c.Backend(nil)
+	// Load the backend
+	b, backendDiags := c.backend(".", view)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/state_show.go

@@ -48,9 +48,10 @@ func (c *StateShowCommand) Run(args []string) int {
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(nil)
-	if backendDiags.HasErrors() {
-		c.showDiagnostics(backendDiags)
+	view := arguments.ViewHuman
+	b, diags := c.backend(".", view)
+	if diags.HasErrors() {
+		c.showDiagnostics(diags)
 		return 1
 	}
 

internal/command/state_test.go

@@ -9,6 +9,7 @@ import (
 	"sort"
 	"testing"
 
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/hashicorp/terraform/internal/states/statemgr"
 )
 
@@ -31,7 +32,8 @@ func TestStateDefaultBackupExtension(t *testing.T) {
 	tmp := t.TempDir()
 	t.Chdir(tmp)
 
-	s, err := (&StateMeta{}).State()
+	view := arguments.ViewHuman
+	s, err := (&StateMeta{}).State(view)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/command/taint.go

@@ -66,7 +66,8 @@ func (c *TaintCommand) Run(args []string) int {
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(nil)
+	view := arguments.ViewHuman
+	b, backendDiags := c.backend(".", view)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/testdata/state-store-unchanged/main.tf

@@ -1,7 +1,8 @@
 terraform {
   required_providers {
     test = {
-      source = "hashicorp/test"
+      source  = "hashicorp/test"
+      version = "1.2.3"
     }
   }
   state_store "test_store" {

internal/command/unlock.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/hashicorp/terraform/internal/states/statemgr"
 
 	"github.com/hashicorp/cli"
@@ -51,17 +52,9 @@ func (c *UnlockCommand) Run(args []string) int {
 
 	var diags tfdiags.Diagnostics
 
-	backendConfig, backendDiags := c.loadBackendConfig(configPath)
-	diags = diags.Append(backendDiags)
-	if diags.HasErrors() {
-		c.showDiagnostics(diags)
-		return 1
-	}
-
 	// Load the backend
-	b, backendDiags := c.Backend(&BackendOpts{
-		BackendConfig: backendConfig,
-	})
+	view := arguments.ViewHuman
+	b, backendDiags := c.backend(configPath, view)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/untaint.go

@@ -56,7 +56,8 @@ func (c *UntaintCommand) Run(args []string) int {
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(nil)
+	view := arguments.ViewHuman
+	b, backendDiags := c.backend(".", view)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/workspace_delete.go

@@ -59,17 +59,9 @@ func (c *WorkspaceDeleteCommand) Run(args []string) int {
 
 	var diags tfdiags.Diagnostics
 
-	backendConfig, backendDiags := c.loadBackendConfig(configPath)
-	diags = diags.Append(backendDiags)
-	if diags.HasErrors() {
-		c.showDiagnostics(diags)
-		return 1
-	}
-
 	// Load the backend
-	b, backendDiags := c.Backend(&BackendOpts{
-		BackendConfig: backendConfig,
-	})
+	view := arguments.ViewHuman
+	b, backendDiags := c.backend(configPath, view)
 	diags = diags.Append(backendDiags)
 	if backendDiags.HasErrors() {
 		c.showDiagnostics(diags)

internal/command/workspace_list.go

@@ -8,7 +8,7 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/hashicorp/terraform/internal/tfdiags"
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/posener/complete"
 )
 
@@ -35,21 +35,10 @@ func (c *WorkspaceListCommand) Run(args []string) int {
 		return 1
 	}
 
-	var diags tfdiags.Diagnostics
-
-	backendConfig, backendDiags := c.loadBackendConfig(configPath)
-	diags = diags.Append(backendDiags)
-	if diags.HasErrors() {
-		c.showDiagnostics(diags)
-		return 1
-	}
-
 	// Load the backend
-	b, backendDiags := c.Backend(&BackendOpts{
-		BackendConfig: backendConfig,
-	})
-	diags = diags.Append(backendDiags)
-	if backendDiags.HasErrors() {
+	view := arguments.ViewHuman
+	b, diags := c.backend(configPath, view)
+	if diags.HasErrors() {
 		c.showDiagnostics(diags)
 		return 1
 	}
@@ -58,6 +47,7 @@ func (c *WorkspaceListCommand) Run(args []string) int {
 	c.ignoreRemoteVersionConflict(b)
 
 	states, wDiags := b.Workspaces()
+	diags = diags.Append(wDiags)
 	if wDiags.HasErrors() {
 		c.Ui.Error(wDiags.Err().Error())
 		return 1

internal/command/workspace_new.go

@@ -68,19 +68,10 @@ func (c *WorkspaceNewCommand) Run(args []string) int {
 
 	var diags tfdiags.Diagnostics
 
-	backendConfig, backendDiags := c.loadBackendConfig(configPath)
-	diags = diags.Append(backendDiags)
-	if diags.HasErrors() {
-		c.showDiagnostics(diags)
-		return 1
-	}
-
 	// Load the backend
-	b, backendDiags := c.Backend(&BackendOpts{
-		BackendConfig: backendConfig,
-	})
-	diags = diags.Append(backendDiags)
-	if backendDiags.HasErrors() {
+	view := arguments.ViewHuman
+	b, diags := c.backend(configPath, view)
+	if diags.HasErrors() {
 		c.showDiagnostics(diags)
 		return 1
 	}

internal/command/workspace_select.go

@@ -8,7 +8,7 @@ import (
 	"strings"
 
 	"github.com/hashicorp/cli"
-	"github.com/hashicorp/terraform/internal/tfdiags"
+	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/posener/complete"
 )
 
@@ -42,15 +42,6 @@ func (c *WorkspaceSelectCommand) Run(args []string) int {
 		return 1
 	}
 
-	var diags tfdiags.Diagnostics
-
-	backendConfig, backendDiags := c.loadBackendConfig(configPath)
-	diags = diags.Append(backendDiags)
-	if diags.HasErrors() {
-		c.showDiagnostics(diags)
-		return 1
-	}
-
 	current, isOverridden := c.WorkspaceOverridden()
 	if isOverridden {
 		c.Ui.Error(envIsOverriddenSelectError)
@@ -58,11 +49,9 @@ func (c *WorkspaceSelectCommand) Run(args []string) int {
 	}
 
 	// Load the backend
-	b, backendDiags := c.Backend(&BackendOpts{
-		BackendConfig: backendConfig,
-	})
-	diags = diags.Append(backendDiags)
-	if backendDiags.HasErrors() {
+	view := arguments.ViewHuman
+	b, diags := c.backend(configPath, view)
+	if diags.HasErrors() {
 		c.showDiagnostics(diags)
 		return 1
 	}