package parse

import (

"strings"

"github.com/moby/buildkit/frontend/dockerfile/parser"

)

func parseWorkdir(node *parser.Node) []Rule {

if node.Next == nil {

return []Rule{invalidInstructionRule(node, "WORKDIR requires exactly one argument")}

}

workdirValue := node.Next

var workdirRules []Rule

if !checkWorkdirAbsolute(workdirValue.Value) {

workdirRules = append(workdirRules, NewWarningRule(node, "WorkdirRelativePath",

"WORKDIR uses a relative path. Consider using an absolute path (starting with /) to avoid issues when the base image's working directory changes.",

"https://docs.docker.com/reference/build-checks/workdir-relative-path/"))

}

return workdirRules

}

// checkWorkdirAbsolute checks if a WORKDIR path is absolute.

// Returns true if the path is absolute, false if it's relative.

// Absolute paths include:

// - Unix absolute paths (starting with /)

// - Windows absolute paths (e.g., C:, C:\, C:/)

// - Variable references (e.g., $HOME, ${WORKDIR}) - considered "absolute enough"

func checkWorkdirAbsolute(workdirPath string) bool {

// Unix absolute path

if strings.HasPrefix(workdirPath, "/") {

return true

}

// Windows absolute path (C:, C:\, C:/)

// Check for drive letter followed by colon

if len(workdirPath) >= 2 && workdirPath[1] == ':' {

// First character should be a letter (drive letter)

firstChar := workdirPath[0]

if (firstChar >= 'A' && firstChar <= 'Z') || (firstChar >= 'a' && firstChar <= 'z') {

return true

}

}

// Variable reference (considered "absolute enough")

// Variables like $HOME, ${WORKDIR}, $APP_HOME are treated as absolute

// since they will be resolved at build time and we can't know if they're absolute

if strings.HasPrefix(workdirPath, "$") {

return true

}

return false

}