feat: add muxt version comment

cmd/muxt/generate.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bytes"
 	"flag"
 	"fmt"
 	"go/token"
@@ -112,5 +113,13 @@ func generateCommand(args []string, workingDirectory string, getEnv func(string)
 	if err != nil {
 		return err
 	}
-	return os.WriteFile(filepath.Join(workingDirectory, g.outputFilename), []byte(CodeGenerationComment+"\n\n"+s), 0o644)
+	var sb bytes.Buffer
+	sb.WriteString(CodeGenerationComment)
+	if v, ok := cliVersion(); ok {
+		sb.WriteString("\n// muxt version: ")
+		sb.WriteString(v)
+		sb.WriteString("\n\n")
+	}
+	sb.WriteString(s)
+	return os.WriteFile(filepath.Join(workingDirectory, g.outputFilename), sb.Bytes(), 0o644)
 }

cmd/muxt/main.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"runtime/debug"
 
 	"rsc.io/script"
 )
@@ -24,6 +25,8 @@ func command(wd string, args []string, getEnv func(string) string, stdout, stder
 		switch cmd, cmdArgs := args[0], args[1:]; cmd {
 		case "generate", "gen", "g":
 			return generateCommand(cmdArgs, wd, getEnv, stdout, stderr)
+		case "version", "v":
+			return versionCommand(stdout)
 		}
 	}
 	return fmt.Errorf("unknown command")
@@ -55,3 +58,17 @@ func scriptCommand() script.Cmd {
 		}, nil
 	})
 }
+
+func versionCommand(stdout io.Writer) error {
+	v, _ := cliVersion()
+	_, err := io.WriteString(stdout, v)
+	return err
+}
+
+func cliVersion() (string, bool) {
+	bi, ok := debug.ReadBuildInfo()
+	if !ok || bi.Main.Version == "" {
+		return "", false
+	}
+	return bi.Main.Version, true
+}

cmd/muxt/testdata/generate/simple_get.txtar

@@ -1,5 +1,8 @@
 muxt generate
 
+cat template_routes.go
+stdout '// muxt version: \(devel\)'
+
 exec go test -cover
 
 -- template.gohtml --