Add clarifying commend and e2e test

This pull request focuses on removing the prompt to rename the default
workspace when it is empty. Functionality already exists to not migrate
an empty workspace. This commit adds some clarifying language in the
comment where we do the evaluation to know whether to ask for a new name
or not. I also added an end to end test, which I should have added to
begin with.

internal/cloud/e2e/migrate_state_multi_to_tfc_test.go

@@ -157,6 +157,77 @@ func Test_migrate_multi_to_tfc_cloud_name_strategy(t *testing.T) {
 				}
 			},
 		},
+		"migrating multiple workspaces to cloud using name strategy; 'default' workspace is empty": {
+			operations: []operationSets{
+				{
+					prep: func(t *testing.T, orgName, dir string) {
+						tfBlock := terraformConfigLocalBackend()
+						writeMainTF(t, tfBlock, dir)
+					},
+					commands: []tfCommand{
+						{
+							command:           []string{"init"},
+							expectedCmdOutput: `Successfully configured the backend "local"!`,
+						},
+						{
+							command:           []string{"workspace", "new", "workspace1"},
+							expectedCmdOutput: `Created and switched to workspace "workspace1"!`,
+						},
+						{
+							command:         []string{"apply", "-auto-approve"},
+							postInputOutput: []string{`Apply complete!`},
+						},
+						{
+							command:           []string{"workspace", "new", "workspace2"},
+							expectedCmdOutput: `Created and switched to workspace "workspace2"!`,
+						},
+						{
+							command:         []string{"apply", "-auto-approve"},
+							postInputOutput: []string{`Apply complete!`},
+						},
+					},
+				},
+				{
+					prep: func(t *testing.T, orgName, dir string) {
+						wsName := "new-workspace"
+						tfBlock := terraformConfigCloudBackendName(orgName, wsName)
+						writeMainTF(t, tfBlock, dir)
+					},
+					commands: []tfCommand{
+						{
+							command:           []string{"init", "-migrate-state"},
+							expectedCmdOutput: `Do you want to copy only your current workspace?`,
+							userInput:         []string{"yes", "yes"},
+							postInputOutput: []string{
+								`Do you want to copy existing state to Terraform Cloud?`,
+								`Terraform Cloud has been successfully initialized!`},
+						},
+						{
+							command:     []string{"workspace", "select", "default"},
+							expectError: true,
+						},
+						{
+							command:           []string{"output"},
+							expectedCmdOutput: `val = "workspace2"`, // this was the output of the current workspace selected before migration
+						},
+					},
+				},
+			},
+			validations: func(t *testing.T, orgName string) {
+				wsList, err := tfeClient.Workspaces.List(ctx, orgName, tfe.WorkspaceListOptions{})
+				if err != nil {
+					t.Fatal(err)
+				}
+				if len(wsList.Items) != 1 {
+					t.Fatalf("Expected the number of workspaces to be 1, but got %d", len(wsList.Items))
+				}
+				ws := wsList.Items[0]
+				// this workspace name is what exists in the cloud backend configuration block
+				if ws.Name != "new-workspace" {
+					t.Fatalf("Expected workspace to be `new-workspace`, but is %s", ws.Name)
+				}
+			},
+		},
 	}
 
 	for name, tc := range cases {
@@ -220,7 +291,7 @@ func Test_migrate_multi_to_tfc_cloud_name_strategy(t *testing.T) {
 					}
 
 					err = cmd.Wait()
-					if err != nil {
+					if err != nil && !tfCmd.expectError {
 						t.Fatal(err)
 					}
 				}

internal/command/meta_backend_migrate.go

@@ -622,10 +622,12 @@ func (m *Meta) backendMigrateState_S_TFC(opts *backendMigrateOpts, sourceWorkspa
 	newCurrentWorkspace := ""
 
 	// This map is used later when doing the migration per source/destination.
-	// If a source has 'default', then we ask what the new name should be.
+	// If a source has 'default' and has state, then we ask what the new name should be.
 	// And further down when we actually run state migration for each
-	// sourc/destination workspce, we use this new name (where source is 'default')
-	// and set as destinationWorkspace.
+	// source/destination workspace, we use this new name (where source is 'default')
+	// and set as destinationWorkspace. If the default workspace does not have
+	// state we will not prompt the user for a new name because empty workspaces
+	// do not get migrated.
 	defaultNewName := map[string]string{}
 	for i := 0; i < len(sourceWorkspaces); i++ {
 		if sourceWorkspaces[i] == backend.DefaultStateName {