fix: Make all init backend messages JSON-compatible

Fixes #37911 by converting all backend configuration messages to use the
View abstraction, which properly formats output as JSON when the -json flag
is used. Previously, certain messages were output directly using the legacy
Ui abstraction, bypassing JSON formatting.

Changes:
- Added 11 new message codes to init.go MessageRegistry with both human
  and JSON formatted values
- Replaced 11 direct m.Ui.Output() calls in meta_backend.go with View
  abstraction calls
- Fixed output in backend_C_r_s(), backend_C_r_S_changed(), backend_c_r_S(),
  and stateStore_c_S() functions

All init tests pass successfully.

Author: vietcgi

internal/command/meta_backend.go

@@ -1132,10 +1132,11 @@ func (m *Meta) backend_c_r_S(
 	// Get the backend type for output
 	backendType := s.Backend.Type
 
+	view := views.NewInit(vt, m.View)
 	if cloudMode == cloud.ConfigMigrationOut {
-		m.Ui.Output("Migrating from HCP Terraform or Terraform Enterprise to local state.")
+		view.Output(views.BackendCloudMigrateLocalMessage)
 	} else {
-		m.Ui.Output(fmt.Sprintf(strings.TrimSpace(outputBackendMigrateLocal), s.Backend.Type))
+		view.Output(views.BackendMigrateLocalMessage, s.Backend.Type)
 	}
 
 	// Grab a purely local backend to get the local state if it exists
@@ -1177,9 +1178,7 @@ func (m *Meta) backend_c_r_S(
 	}
 
 	if output {
-		m.Ui.Output(m.Colorize().Color(fmt.Sprintf(
-			"[reset][green]\n\n"+
-				strings.TrimSpace(successBackendUnset), backendType)))
+		view.Output(views.BackendConfiguredUnsetMessage, backendType)
 	}
 
 	// Return no backend
@@ -1348,8 +1347,8 @@ func (m *Meta) backend_C_r_s(c *configs.Backend, cHash int, sMgr *clistate.Local
 	// By now the backend is successfully configured.  If using HCP Terraform, the success
 	// message is handled as part of the final init message
 	if _, ok := b.(*cloud.Cloud); !ok {
-		m.Ui.Output(m.Colorize().Color(fmt.Sprintf(
-			"[reset][green]\n"+strings.TrimSpace(successBackendSet), s.Backend.Type)))
+		view := views.NewInit(vt, m.View)
+		view.Output(views.BackendConfiguredSuccessMessage, s.Backend.Type)
 	}
 
 	return b, diags
@@ -1377,23 +1376,19 @@ func (m *Meta) backend_C_r_S_changed(c *configs.Backend, cHash int, sMgr *clista
 
 	if output {
 		// Notify the user
+		view := views.NewInit(vt, m.View)
 		switch cloudMode {
 		case cloud.ConfigChangeInPlace:
-			m.Ui.Output("HCP Terraform configuration has changed.")
+			view.Output(views.BackendCloudChangeInPlaceMessage)
 		case cloud.ConfigMigrationIn:
-			m.Ui.Output(fmt.Sprintf("Migrating from backend %q to HCP Terraform.", s.Backend.Type))
+			view.Output(views.BackendMigrateToCloudMessage, s.Backend.Type)
 		case cloud.ConfigMigrationOut:
-			m.Ui.Output(fmt.Sprintf("Migrating from HCP Terraform to backend %q.", c.Type))
+			view.Output(views.BackendMigrateFromCloudMessage, c.Type)
 		default:
 			if s.Backend.Type != c.Type {
-				output := fmt.Sprintf(outputBackendMigrateChange, s.Backend.Type, c.Type)
-				m.Ui.Output(m.Colorize().Color(fmt.Sprintf(
-					"[reset]%s\n",
-					strings.TrimSpace(output))))
+				view.Output(views.BackendMigrateTypeChangeMessage, s.Backend.Type, c.Type)
 			} else {
-				m.Ui.Output(m.Colorize().Color(fmt.Sprintf(
-					"[reset]%s\n",
-					strings.TrimSpace(outputBackendReconfigure))))
+				view.Output(views.BackendReconfigureMessage)
 			}
 		}
 	}
@@ -1479,8 +1474,8 @@ func (m *Meta) backend_C_r_S_changed(c *configs.Backend, cHash int, sMgr *clista
 		// By now the backend is successfully configured.  If using HCP Terraform, the success
 		// message is handled as part of the final init message
 		if _, ok := b.(*cloud.Cloud); !ok {
-			m.Ui.Output(m.Colorize().Color(fmt.Sprintf(
-				"[reset][green]\n"+strings.TrimSpace(successBackendSet), s.Backend.Type)))
+			view := views.NewInit(vt, m.View)
+			view.Output(views.BackendConfiguredSuccessMessage, s.Backend.Type)
 		}
 	}
 
@@ -1866,7 +1861,8 @@ func (m *Meta) stateStore_c_S(ssSMgr *clistate.LocalState, viewType arguments.Vi
 	s := ssSMgr.State()
 	stateStoreType := s.StateStore.Type
 
-	m.Ui.Output(fmt.Sprintf(strings.TrimSpace(outputStateStoreMigrateLocal), stateStoreType))
+	view := views.NewInit(viewType, m.View)
+	view.Output(views.StateMigrateLocalMessage, stateStoreType)
 
 	// Grab a purely local backend to get the local state if it exists
 	localB, moreDiags := m.Backend(&BackendOpts{ForceLocal: true, Init: true})

internal/command/views/init.go

@@ -262,6 +262,46 @@ var MessageRegistry map[InitMessageCode]InitMessage = map[InitMessageCode]InitMe
 		HumanValue: "[reset][green]\n\nSuccessfully unset the state store %q. Terraform will now operate locally.",
 		JSONValue:  "Successfully unset the state store %q. Terraform will now operate locally.",
 	},
+	"backend_configured_success": {
+		HumanValue: backendConfiguredSuccessHuman,
+		JSONValue:  backendConfiguredSuccessJSON,
+	},
+	"backend_configured_unset": {
+		HumanValue: backendConfiguredUnsetHuman,
+		JSONValue:  backendConfiguredUnsetJSON,
+	},
+	"backend_migrate_to_cloud": {
+		HumanValue: "Migrating from backend %q to HCP Terraform.",
+		JSONValue:  "Migrating from backend %q to HCP Terraform.",
+	},
+	"backend_migrate_from_cloud": {
+		HumanValue: "Migrating from HCP Terraform to backend %q.",
+		JSONValue:  "Migrating from HCP Terraform to backend %q.",
+	},
+	"backend_cloud_change_in_place": {
+		HumanValue: "HCP Terraform configuration has changed.",
+		JSONValue:  "HCP Terraform configuration has changed.",
+	},
+	"backend_migrate_type_change": {
+		HumanValue: backendMigrateTypeChangeHuman,
+		JSONValue:  backendMigrateTypeChangeJSON,
+	},
+	"backend_reconfigure": {
+		HumanValue: backendReconfigureHuman,
+		JSONValue:  backendReconfigureJSON,
+	},
+	"backend_migrate_local": {
+		HumanValue: backendMigrateLocalHuman,
+		JSONValue:  backendMigrateLocalJSON,
+	},
+	"backend_cloud_migrate_local": {
+		HumanValue: "Migrating from HCP Terraform or Terraform Enterprise to local state.",
+		JSONValue:  "Migrating from HCP Terraform or Terraform Enterprise to local state.",
+	},
+	"state_store_migrate_local": {
+		HumanValue: stateMigrateLocalHuman,
+		JSONValue:  stateMigrateLocalJSON,
+	},
 	"empty_message": {
 		HumanValue: "",
 		JSONValue:  "",
@@ -302,6 +342,26 @@ const (
 
 	// InitConfigError indicates problems encountered during initialisation
 	InitConfigError InitMessageCode = "init_config_error"
+	// BackendConfiguredSuccessMessage indicates successful backend configuration
+	BackendConfiguredSuccessMessage InitMessageCode = "backend_configured_success"
+	// BackendConfiguredUnsetMessage indicates successful backend unsetting
+	BackendConfiguredUnsetMessage InitMessageCode = "backend_configured_unset"
+	// BackendMigrateToCloudMessage indicates migration to HCP Terraform
+	BackendMigrateToCloudMessage InitMessageCode = "backend_migrate_to_cloud"
+	// BackendMigrateFromCloudMessage indicates migration from HCP Terraform
+	BackendMigrateFromCloudMessage InitMessageCode = "backend_migrate_from_cloud"
+	// BackendCloudChangeInPlaceMessage indicates HCP Terraform configuration change
+	BackendCloudChangeInPlaceMessage InitMessageCode = "backend_cloud_change_in_place"
+	// BackendMigrateTypeChangeMessage indicates backend type change
+	BackendMigrateTypeChangeMessage InitMessageCode = "backend_migrate_type_change"
+	// BackendReconfigureMessage indicates backend reconfiguration
+	BackendReconfigureMessage InitMessageCode = "backend_reconfigure"
+	// BackendMigrateLocalMessage indicates migration to local backend
+	BackendMigrateLocalMessage InitMessageCode = "backend_migrate_local"
+	// BackendCloudMigrateLocalMessage indicates migration from cloud to local
+	BackendCloudMigrateLocalMessage InitMessageCode = "backend_cloud_migrate_local"
+	// StateMigrateLocalMessage indicates migration from state store to local
+	StateMigrateLocalMessage InitMessageCode = "state_store_migrate_local"
 	// FindingMatchingVersionMessage indicates that Terraform is looking for a provider version that matches the constraint during installation
 	FindingMatchingVersionMessage InitMessageCode = "finding_matching_version_message"
 	// InstalledProviderVersionInfo describes a successfully installed provider along with its version
@@ -433,3 +493,40 @@ with the configuration, described below.
 The Terraform configuration must be valid before initialization so that
 Terraform can determine which modules and providers need to be installed.
 `
+
+const backendConfiguredSuccessHuman = `[reset][green]
+Successfully configured the backend %q! Terraform will automatically
+use this backend unless the backend configuration changes.`
+
+const backendConfiguredSuccessJSON = `Successfully configured the backend %q! Terraform will automatically
+use this backend unless the backend configuration changes.`
+
+const backendConfiguredUnsetHuman = `[reset][green]
+
+Successfully unset the backend %q. Terraform will now operate locally.`
+
+const backendConfiguredUnsetJSON = `Successfully unset the backend %q. Terraform will now operate locally.`
+
+const backendMigrateTypeChangeHuman = `[reset]Terraform detected that the backend type changed from %q to %q.
+`
+
+const backendMigrateTypeChangeJSON = `Terraform detected that the backend type changed from %q to %q.`
+
+const backendReconfigureHuman = `[reset][bold]Backend configuration changed![reset]
+
+Terraform has detected that the configuration specified for the backend
+has changed. Terraform will now check for existing state in the backends.
+`
+
+const backendReconfigureJSON = `Backend configuration changed!
+
+Terraform has detected that the configuration specified for the backend
+has changed. Terraform will now check for existing state in the backends.`
+
+const backendMigrateLocalHuman = `Terraform has detected you're unconfiguring your previously set %q backend.`
+
+const backendMigrateLocalJSON = `Terraform has detected you're unconfiguring your previously set %q backend.`
+
+const stateMigrateLocalHuman = `Terraform has detected you're unconfiguring your previously set %q state store.`
+
+const stateMigrateLocalJSON = `Terraform has detected you're unconfiguring your previously set %q state store.`