fix(json): standardize JSON output for errors and empty arrays (bd-au0.7)

- Add FatalErrorRespectJSON helper for JSON-aware error output
- Fix bd comments list returning null instead of [] for empty arrays
- Remove redundant local --json flags from show/update/close commands
  that were shadowing the global persistent --json flag
- Update show command error handlers to use FatalErrorRespectJSON

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

cmd/bd/comments.go

@@ -35,7 +35,7 @@ Examples:
 	Run: func(cmd *cobra.Command, args []string) {
 		issueID := args[0]
 
-		var comments []*types.Comment
+		comments := make([]*types.Comment, 0)
 		usedDaemon := false
 		if daemonClient != nil {
 			resp, err := daemonClient.ListComments(&rpc.CommentListArgs{ID: issueID})
@@ -79,6 +79,11 @@ Examples:
 			comments = result
 		}
 
+		// Normalize nil to empty slice for consistent JSON output
+		if comments == nil {
+			comments = make([]*types.Comment, 0)
+		}
+
 		if jsonOutput {
 			data, err := json.MarshalIndent(comments, "", "  ")
 			if err != nil {

cmd/bd/errors.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 )
@@ -23,6 +24,28 @@ func FatalError(format string, args ...interface{}) {
 	os.Exit(1)
 }
 
+// FatalErrorRespectJSON writes an error message and exits with code 1.
+// If --json flag is set, outputs structured JSON to stdout.
+// Otherwise, outputs plain text to stderr.
+//
+// Use this for errors in commands that support --json output.
+//
+// Example:
+//
+//	if err := store.GetIssue(ctx, id); err != nil {
+//	    FatalErrorRespectJSON("%v", err)
+//	}
+func FatalErrorRespectJSON(format string, args ...interface{}) {
+	msg := fmt.Sprintf(format, args...)
+	if jsonOutput {
+		data, _ := json.MarshalIndent(map[string]string{"error": msg}, "", "  ")
+		fmt.Println(string(data))
+	} else {
+		fmt.Fprintf(os.Stderr, "Error: %s\n", msg)
+	}
+	os.Exit(1)
+}
+
 // FatalErrorWithHint writes an error message with a hint to stderr and exits.
 // Use this when you can provide an actionable suggestion to fix the error.
 //

cmd/bd/show.go

@@ -26,7 +26,6 @@ var showCmd = &cobra.Command{
 	Short:   "Show issue details",
 	Args:    cobra.MinimumNArgs(1),
 	Run: func(cmd *cobra.Command, args []string) {
-		jsonOutput, _ := cmd.Flags().GetBool("json")
 		showThread, _ := cmd.Flags().GetBool("thread")
 		ctx := rootCtx
 
@@ -34,8 +33,7 @@ var showCmd = &cobra.Command{
 		// Skip check when using daemon (daemon auto-imports on staleness)
 		if daemonClient == nil {
 			if err := ensureDatabaseFresh(ctx); err != nil {
-				fmt.Fprintf(os.Stderr, "Error: %v\n", err)
-				os.Exit(1)
+				FatalErrorRespectJSON("%v", err)
 			}
 		}
 
@@ -47,13 +45,11 @@ var showCmd = &cobra.Command{
 				resolveArgs := &rpc.ResolveIDArgs{ID: id}
 				resp, err := daemonClient.ResolveID(resolveArgs)
 				if err != nil {
-					fmt.Fprintf(os.Stderr, "Error resolving ID %s: %v\n", id, err)
-					os.Exit(1)
+					FatalErrorRespectJSON("resolving ID %s: %v", id, err)
 				}
 				var resolvedID string
 				if err := json.Unmarshal(resp.Data, &resolvedID); err != nil {
-					fmt.Fprintf(os.Stderr, "Error unmarshaling resolved ID: %v\n", err)
-					os.Exit(1)
+					FatalErrorRespectJSON("unmarshaling resolved ID: %v", err)
 				}
 				resolvedIDs = append(resolvedIDs, resolvedID)
 			}
@@ -62,8 +58,7 @@ var showCmd = &cobra.Command{
 			var err error
 			resolvedIDs, err = utils.ResolvePartialIDs(ctx, store, args)
 			if err != nil {
-				fmt.Fprintf(os.Stderr, "Error: %v\n", err)
-				os.Exit(1)
+				FatalErrorRespectJSON("%v", err)
 			}
 		}
 
@@ -466,7 +461,6 @@ var updateCmd = &cobra.Command{
 	Args:    cobra.MinimumNArgs(1),
 	Run: func(cmd *cobra.Command, args []string) {
 		CheckReadonly("update")
-		jsonOutput, _ := cmd.Flags().GetBool("json")
 		updates := make(map[string]interface{})
 
 		if cmd.Flags().Changed("status") {
@@ -975,7 +969,6 @@ var closeCmd = &cobra.Command{
 		if reason == "" {
 			reason = "Closed"
 		}
-		jsonOutput, _ := cmd.Flags().GetBool("json")
 		force, _ := cmd.Flags().GetBool("force")
 		continueFlag, _ := cmd.Flags().GetBool("continue")
 		noAuto, _ := cmd.Flags().GetBool("no-auto")
@@ -1383,7 +1376,6 @@ func findReplies(ctx context.Context, issueID string, daemonClient *rpc.Client,
 }
 
 func init() {
-	showCmd.Flags().Bool("json", false, "Output JSON format")
 	showCmd.Flags().Bool("thread", false, "Show full conversation thread (for messages)")
 	rootCmd.AddCommand(showCmd)
 
@@ -1399,8 +1391,6 @@ func init() {
 	updateCmd.Flags().StringSlice("add-label", nil, "Add labels (repeatable)")
 	updateCmd.Flags().StringSlice("remove-label", nil, "Remove labels (repeatable)")
 	updateCmd.Flags().StringSlice("set-labels", nil, "Set labels, replacing all existing (repeatable)")
-
-	updateCmd.Flags().Bool("json", false, "Output JSON format")
 	rootCmd.AddCommand(updateCmd)
 
 	editCmd.Flags().Bool("title", false, "Edit the title")
@@ -1411,7 +1401,6 @@ func init() {
 	rootCmd.AddCommand(editCmd)
 
 	closeCmd.Flags().StringP("reason", "r", "", "Reason for closing")
-	closeCmd.Flags().Bool("json", false, "Output JSON format")
 	closeCmd.Flags().BoolP("force", "f", false, "Force close pinned issues")
 	closeCmd.Flags().Bool("continue", false, "Auto-advance to next step in molecule")
 	closeCmd.Flags().Bool("no-auto", false, "With --continue, show next step but don't claim it")