added addtags command

workaround for golang/go#47179

Author: Code-Hex

cmd/addtags/main.go

@@ -0,0 +1,76 @@
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/build/constraint"
+	"go/format"
+	"os"
+	"os/exec"
+)
+
+var (
+	tags = flag.String("tags", "", "comma-separated list of build tags to apply")
+	file = flag.String("file", "", "file to modify")
+)
+
+func usage() {
+	fmt.Fprintf(os.Stderr, `
+usage: addtags -tags <build tags to apply> -file FILE <subcommand args...>
+`[1:])
+
+	flag.PrintDefaults()
+	fmt.Fprintf(os.Stderr, `
+It is intended for use with 'go generate', so it also runs a subcommand,
+which presumably creates the file.
+Sample usage:
+addtags -tags=darwin,arm64 -file linuxrosettaavailability_string.go stringer -type=LinuxRosettaAvailability
+`[1:])
+	os.Exit(2)
+}
+
+func main() {
+	flag.Usage = usage
+	flag.Parse()
+	args := flag.Args()
+	if len(args) == 0 {
+		flag.Usage()
+	}
+	plusConstraint := fmt.Sprintf("// +build %s", *tags)
+	expr, err := constraint.Parse(plusConstraint)
+	check(err)
+	goBuildConstraint := fmt.Sprintf("//go:build %s", expr.String())
+
+	cmd := exec.Command(args[0], args[1:]...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	err = cmd.Run()
+	check(err)
+	b, err := os.ReadFile(*file)
+	check(err)
+
+	var buf bytes.Buffer
+	_, err = fmt.Fprintf(&buf, "%s\n%s\n", goBuildConstraint, plusConstraint)
+	check(err)
+
+	_, err = buf.Write(b)
+	check(err)
+
+	src, err := format.Source(buf.Bytes())
+	check(err)
+
+	f, err := os.OpenFile(*file, os.O_TRUNC|os.O_WRONLY, 0644)
+	check(err)
+	defer f.Close()
+
+	_, err = f.Write(src)
+	check(err)
+}
+
+func check(err error) {
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}

linuxrosettaavailability_string.go renamed to linuxrosettaavailability_string_arm64.go

@@ -17,7 +17,7 @@ import (
 
 // LinuxRosettaAvailability represents an availability of Rosetta support for Linux binaries.
 //
-//go:generate stringer -type=LinuxRosettaAvailability
+//go:generate go run ./cmd/addtags -tags=darwin,arm64 -file linuxrosettaavailability_string_arm64.go stringer -type=LinuxRosettaAvailability -output=linuxrosettaavailability_string_arm64.go
 type LinuxRosettaAvailability int
 
 const (