grpc-ecosystem/grpc-gateway · error

usage: openapiv3-merge FILE [FILE ...]

Error message

usage: openapiv3-merge FILE [FILE ...]

What it means

Usage error returned by the openapiv3-merge CLI entry point run(): it was invoked with zero FILE arguments. The tool requires one or more OpenAPI JSON documents to merge; without args there is nothing to merge, so it reports usage and main exits with status 1.

Source

Thrown at openapiv3-merge/main.go:40

	"fmt"
	"io"
	"os"

	"github.com/grpc-ecosystem/grpc-gateway/v2/openapiv3-merge/internal/merge"
)

func main() {
	if err := run(os.Args[1:], os.Stdout); err != nil {
		fmt.Fprintln(os.Stderr, "openapiv3-merge:", err)
		os.Exit(1)
	}
}

// run is the testable entry point. It accepts the program's arguments (no
// program name) and the writer to emit the merged document to.
func run(args []string, out io.Writer) error {
	if len(args) == 0 {
		return errors.New("usage: openapiv3-merge FILE [FILE ...]")
	}
	inputs := make([]merge.Input, 0, len(args))
	for _, path := range args {
		data, err := os.ReadFile(path)
		if err != nil {
			return fmt.Errorf("read %s: %w", path, err)
		}
		inputs = append(inputs, merge.Input{Name: path, Data: data})
	}
	merged, err := merge.Merge(inputs)
	if err != nil {
		return err
	}
	if _, err := out.Write(merged); err != nil {
		return err
	}
	if _, err := io.WriteString(out, "\n"); err != nil {
		return err

View on GitHub (pinned to a58a4436a3)

Solutions

1. Run the tool with at least one file: openapiv3-merge FILE [FILE ...].
2. Check shell quoting/globbing if arguments were expected but not received.

When it happens

Trigger: Thrown at openapiv3-merge/main.go:40 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grpc-ecosystem/grpc-gateway@a58a4436a3 (2026-09-02). Data as JSON: /api/errors/81c8c1308aeee093. Report an issue: GitHub.