The use of text/template disables dead code elimination in all users of cobra

[alexander-hirth]

Any use of reflect.Value.MethodByName() or reflect.Type.MethodByName() disables the DCE. The compiler assumes that these functions will look any method up, and cannot remove methods even if they are never called.

text/template is a very notable offender in this respect. It calls MethodByName() with random strings extracted from template texts.

Command::UsageFunc() and Command::HelpFunc() use text/template, hence they disable the DCE for all users of cobra. Since cobra is the go-to module to implement CLIs, this essentially disables DCE in all command line tools written in go.

A low-level library that is used by almost everyone should not pessimise the code generation by disabling the DCE. I'd avoid text/template altogether.

[aderouineau]

I would like to +1 this. When building the very small code below, the binary is almost 40MB. When removing context.WithValue(), it's about 5MB.

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/aws/aws-sdk-go-v2/service/ec2"
	"github.com/spf13/cobra"
)

func main() {
	ctx := context.Background()
	ctx = context.WithValue(ctx, "ec2Client", &ec2.Client{})

	rootCmd := &cobra.Command{}

	if err := rootCmd.ExecuteContext(ctx); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}

@alexander-hirth Have you found an alternative?

[marckhouzam]

See #1956