cmd/rofl: Output trust-root as JSON

The `trust-root` command previously printed a Rust struct literal. Emit
standard indented JSON instead so the output is easier to consume
programmatically.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: anzoman

cmd/rofl/trust_root.go

@@ -2,6 +2,7 @@ package rofl
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 
 	"github.com/spf13/cobra"
@@ -12,6 +13,14 @@ import (
 	cliConfig "github.com/oasisprotocol/cli/config"
 )
 
+// trustRoot is the consensus trust root for a ROFL application.
+type trustRoot struct {
+	Height       uint64 `json:"height"`
+	Hash         string `json:"hash"`
+	RuntimeID    string `json:"runtime_id"`
+	ChainContext string `json:"chain_context"`
+}
+
 var trustRootCmd = &cobra.Command{
 	Use:   "trust-root",
 	Short: "Show a recent trust root for a ROFL application",
@@ -36,13 +45,16 @@ var trustRootCmd = &cobra.Command{
 		blk, err := conn.Consensus().Core().GetBlock(ctx, height)
 		cobra.CheckErr(err)
 
-		// TODO: Support different output formats.
-		fmt.Printf("TrustRoot {\n")
-		fmt.Printf("    height: %d,\n", height)
-		fmt.Printf("    hash: \"%s\".into(),\n", blk.Hash)
-		fmt.Printf("    runtime_id: \"%s\".into(),\n", npa.ParaTime.ID)
-		fmt.Printf("    chain_context: \"%s\".to_string(),\n", npa.Network.ChainContext)
-		fmt.Printf("}\n")
+		tr := trustRoot{
+			Height:       uint64(height),
+			Hash:         blk.Hash.Hex(),
+			RuntimeID:    npa.ParaTime.ID,
+			ChainContext: npa.Network.ChainContext,
+		}
+
+		out, err := json.MarshalIndent(tr, "", "  ")
+		cobra.CheckErr(err)
+		fmt.Println(string(out))
 	},
 }
 

examples/rofl/trust-root.out.static

@@ -1,6 +1,6 @@
-TrustRoot {
-    height: 1022,
-    hash: "bb3e63d729dd568ce07b37eea33eddf8082ed4cacbd64097aad32168a4a4fc9a".into(),
-    runtime_id: "8000000000000000000000000000000000000000000000000000000000000000".into(),
-    chain_context: "074f5ba071c4385a7ad24aea0a3a7b137901395e8f3b35479c1cce87d3170f4e".to_string(),
+{
+  "height": 1022,
+  "hash": "bb3e63d729dd568ce07b37eea33eddf8082ed4cacbd64097aad32168a4a4fc9a",
+  "runtime_id": "8000000000000000000000000000000000000000000000000000000000000000",
+  "chain_context": "074f5ba071c4385a7ad24aea0a3a7b137901395e8f3b35479c1cce87d3170f4e"
 }