From ad507dc74b5380c316940802d1970492d38eec93 Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Mon, 9 Dec 2024 22:57:48 +0100
Subject: [PATCH] cmd/evm: print error for unknown trace format

---
 cmd/evm/main.go | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/cmd/evm/main.go b/cmd/evm/main.go
index e427e8d94e..0e6f6fa5be 100644
--- a/cmd/evm/main.go
+++ b/cmd/evm/main.go
@@ -239,13 +239,20 @@ func tracerFromFlags(ctx *cli.Context) *tracing.Hooks {
 		EnableReturnData: !ctx.Bool(TraceDisableReturnDataFlag.Name),
 	}
 	switch {
-	case ctx.Bool(TraceFlag.Name) && ctx.String(TraceFormatFlag.Name) == "struct":
-		return logger.NewStreamingStructLogger(config, os.Stderr).Hooks()
-	case ctx.Bool(TraceFlag.Name) && ctx.String(TraceFormatFlag.Name) == "json":
-		return logger.NewJSONLogger(config, os.Stderr)
-	case ctx.Bool(TraceFlag.Name) &&
-		(ctx.String(TraceFormatFlag.Name) == "md" || ctx.String(TraceFormatFlag.Name) == "markdown"):
-		return logger.NewMarkdownLogger(config, os.Stderr).Hooks()
+	case ctx.Bool(TraceFlag.Name):
+		switch format := ctx.String(TraceFormatFlag.Name); format {
+		case "struct":
+			return logger.NewStreamingStructLogger(config, os.Stderr).Hooks()
+		case "json":
+			return logger.NewJSONLogger(config, os.Stderr)
+		case "md", "markdown":
+			return logger.NewMarkdownLogger(config, os.Stderr).Hooks()
+		default:
+			fmt.Fprintf(os.Stderr, "unknown trace format: %q\n", format)
+			os.Exit(1)
+			return nil
+		}
+	// Deprecated ways of configuring tracing.
 	case ctx.Bool(MachineFlag.Name):
 		return logger.NewJSONLogger(config, os.Stderr)
 	case ctx.Bool(DebugFlag.Name):