zabio3/godolint

package rules

import (
    "strings"

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

// validateDL3019 Use the `--no-cache` switch to avoid the need to use `--update` and remove `/var/cache/apk/*` when done installing packages
func validateDL3019(node *parser.Node) (rst []ValidateResult, err error) {
    for _, child := range node.Children {
        if child.Value == RUN && isDL3019Error(child) {
            rst = append(rst, ValidateResult{line: child.StartLine})
        }
    }
    return rst, nil
}

func isDL3019Error(node *parser.Node) bool {
    var isApk, isRm bool
    for _, v := range strings.Fields(node.Next.Value) {
        switch v {
        case "apk":
            isApk = true
        case "update":
            if isApk {
                return true
            }
        case "rm":
            if isApk {
                isRm = true
            }
        case "/var/cache/apk/*":
            if isRm {
                return true
            }
        case "&&":
            isApk = false
        }
    }

    return false
}