Use terminfo instead of hardcoding a list of terminals

[vincentbernat]

Hey!

You should use terminfo instead of relying on the terminal name in TERM. This can provide you the number of colors supported. Otherwise, you are missing a lot of terminals supporting colors, like rxvt or screen. In Go, it seems https://github.com/xo/terminfo can do that. It also seems to handle some edge cases for terminals not using the correct TERM. It also handles the special case of true color which was not available through terminfo until recently and is able to fallback to COLORTERM (but it should be using Tc if available).

[Delta456]

Please use this instead of hardcore logic 🙏

[Delta456]

Also WSL has true color support.

[Delta456]

Here's how I did it https://github.com/Delta456/box-cli-maker/blob/dev/util.go, see detectTerminalColor function

[inhere]

ok, thanks

[Delta456]

I found this from https://www.github.com/chalk/supports-color/tree/master/index.js

  // Windows 10 build 10586 is the first Windows release that supports 256 colors.
        // Windows 10 build 14931 is the first release that supports 16m/TrueColor

[inhere]

hi @vincentbernat @Delta456

Thanks you.

I refer xo/terminfo.detectColorLevelFromEnv and https://github.com/Delta456/box-cli-maker, rewrite the detect method: detectTermColorLevel()

code please see https://github.com/gookit/color/blob/master/detect_env.go

[Delta456]

@inhere Amazing! Would appreciate if you could also add my repo as reference in the REAMDE.md.

[Delta456]

Also I believe you could had imported my module and used it instead of making one.

[inhere]

hi @Delta456

Your module also has some problems, please see my detection code

color/detect_env.go

Lines 31 to 156 in 1459bf6

	func detectTermColorLevel() (level terminfo.ColorLevel, needVTP bool) {
	var err error
	// on windows WSL:
	// - runtime.GOOS == "Linux"
	// - support true-color
	// env:
	// WSL_DISTRO_NAME=Debian
	if val := os.Getenv("WSL_DISTRO_NAME"); val != "" {
	// detect WSL as it has True Color support
	if detectWSL() {
	debugf("True Color support on WSL environment")
	return terminfo.ColorLevelMillions, false
	}
	}
	isWin := runtime.GOOS == "windows"
	// TERM=screen
	termVal := os.Getenv("TERM")
	// on `screen` not support True-color
	if termVal != "screen" {
	// On JetBrains Terminal
	// - support true-color
	// TERMINAL_EMULATOR=JetBrains-JediTerm
	val := os.Getenv("TERMINAL_EMULATOR")
	if val == "JetBrains-JediTerm" {
	debugf("True Color support on JetBrains-JediTerm, is win: %v", isWin)
	return terminfo.ColorLevelMillions, isWin
	}
	}
	// level, err = terminfo.ColorLevelFromEnv()
	level, err = detectColorLevelFromEnv(termVal)
	// fmt.Println(level.String(), err)
	// debugf("color level by terminfo.ColorLevelFromEnv(): %s", level)
	if err != nil {
	// if on windows OS
	if isWin {
	debugf("fallback1 check special term color on windows")
	level, needVTP = detectSpecialTermColor()
	} else {
	saveInternalError(err)
	}
	return
	}
	// enable VTP as it has True Color support
	if level == terminfo.ColorLevelNone && isWin {
	debugf("fallback2 check special term color on windows")
	level, needVTP = detectSpecialTermColor()
	}
	return
	}
	// detectColorFromEnv returns the color level COLORTERM, FORCE_COLOR,
	// TERM_PROGRAM, or determined from the TERM environment variable.
	//
	// refer the terminfo.ColorLevelFromEnv()
	func detectColorLevelFromEnv(termVal string) (terminfo.ColorLevel, error) {
	// on TERM=screen: not support true-color
	// termVal := os.Getenv("TERM")
	// check for overriding environment variables
	colorTerm, termProg, forceColor := os.Getenv("COLORTERM"), os.Getenv("TERM_PROGRAM"), os.Getenv("FORCE_COLOR")
	switch {
	case strings.Contains(colorTerm, "truecolor") || strings.Contains(colorTerm, "24bit") || termProg == "Hyper":
	if termVal == "screen" { // on TERM=screen: not support true-color
	return terminfo.ColorLevelHundreds, nil
	}
	return terminfo.ColorLevelMillions, nil
	case colorTerm != "" || forceColor != "":
	return terminfo.ColorLevelBasic, nil
	case termProg == "Apple_Terminal":
	return terminfo.ColorLevelHundreds, nil
	case termProg == "Terminus":
	if termVal == "screen" { // on TERM=screen: not support true-color
	return terminfo.ColorLevelHundreds, nil
	}
	return terminfo.ColorLevelMillions, nil
	case termProg == "iTerm.app":
	if termVal == "screen" { // on TERM=screen: not support true-color
	return terminfo.ColorLevelHundreds, nil
	}
	// check version
	ver := os.Getenv("TERM_PROGRAM_VERSION")
	if ver == "" {
	return terminfo.ColorLevelHundreds, nil
	}
	i, err := strconv.Atoi(strings.Split(ver, ".")[0])
	if err != nil {
	return terminfo.ColorLevelNone, terminfo.ErrInvalidTermProgramVersion
	}
	if i == 3 {
	return terminfo.ColorLevelMillions, nil
	}
	return terminfo.ColorLevelHundreds, nil
	}
	// otherwise determine from TERM's max_colors capability
	if termVal != "" {
	ti, err := terminfo.Load(termVal)
	if err != nil {
	return terminfo.ColorLevelNone, err
	}
	// on TERM=screen:
	// - support 256, not support true-color. test on macOS
	if termVal == "screen" {
	return terminfo.ColorLevelHundreds, nil
	}
	v, ok := ti.Nums[terminfo.MaxColors]
	switch {
	case !ok || v <= 16:
	return terminfo.ColorLevelNone, nil
	case ok && v >= 256:
	return terminfo.ColorLevelHundreds, nil
	}
	return terminfo.ColorLevelBasic, nil
	}
	// Not TERM env value. default return none level
	return terminfo.ColorLevelNone, nil
	// return terminfo.ColorLevelBasic, nil
	}

And my package as the base package, can not rely on your application package in reverse. :)