Fix various nits

Signed-off-by: Gabriel Adrian Samfira <gsamfira@cloudbasesolutions.com>

Author: gabriel-samfira

client/llb/fileop.go

@@ -5,7 +5,6 @@ import (
 	_ "crypto/sha256" // for opencontainers/go-digest
 	"os"
 	"path"
-	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -523,9 +522,7 @@ func (a *fileActionCopy) toProtoAction(ctx context.Context, parent string, base
 }
 
 func (a *fileActionCopy) sourcePath(ctx context.Context) (string, error) {
-	// filepath.Clean() also does a filepath.FromSlash(). Explicitly convert back to UNIX path
-	// separators.
-	p := filepath.ToSlash(filepath.Clean(a.src))
+	p := path.Clean(a.src)
 	dir := "/"
 	var err error
 	if !path.IsAbs(p) {

frontend/dockerfile/dockerfile2llb/convert.go

@@ -1185,7 +1185,7 @@ func dispatchCopy(d *dispatchState, cfg copyConfig) error {
 		}}, copyOpt...)
 
 		if a == nil {
-			a = llb.Copy(st, filepath.ToSlash(f), dest, opts...)
+			a = llb.Copy(st, system.ToSlash(f, d.platform.OS), dest, opts...)
 		} else {
 			a = a.Copy(st, filepath.ToSlash(f), dest, opts...)
 		}
@@ -1423,11 +1423,11 @@ func pathRelativeToWorkingDir(s llb.State, p string, platform ocispecs.Platform)
 	}
 	p, err = system.CheckSystemDriveAndRemoveDriveLetter(p, platform.OS)
 	if err != nil {
-		return "", errors.Wrap(err, "remving drive letter")
+		return "", errors.Wrap(err, "removing drive letter")
 	}
 
 	if system.IsAbs(p, platform.OS) {
-		return p, nil
+		return system.NormalizePath("/", p, platform.OS, false)
 	}
 	return system.NormalizePath(dir, p, platform.OS, false)
 }

solver/llbsolver/file/backend.go

@@ -352,13 +352,14 @@ func cleanPath(s string) (string, error) {
 	if err != nil {
 		return "", errors.Wrap(err, "removing drive letter")
 	}
+	s = filepath.FromSlash(s)
 	s2 := filepath.Join("/", s)
-	if strings.HasSuffix(filepath.FromSlash(s), string(filepath.Separator)+".") {
+	if strings.HasSuffix(s, string(filepath.Separator)+".") {
 		if s2 != string(filepath.Separator) {
 			s2 += string(filepath.Separator)
 		}
 		s2 += "."
-	} else if strings.HasSuffix(filepath.FromSlash(s), string(filepath.Separator)) && s2 != string(filepath.Separator) {
+	} else if strings.HasSuffix(s, string(filepath.Separator)) && s2 != string(filepath.Separator) {
 		s2 += string(filepath.Separator)
 	}
 	return s2, nil

util/system/path.go

@@ -86,11 +86,10 @@ func NormalizePath(parent, newPath, inputOS string, keepSlash bool) (string, err
 }
 
 func ToSlash(inputPath, inputOS string) string {
-	separator := "/"
-	if inputOS == "windows" {
-		separator = "\\"
+	if inputOS != "windows" {
+		return inputPath
 	}
-	return strings.Replace(inputPath, separator, "/", -1)
+	return strings.Replace(inputPath, "\\", "/", -1)
 }
 
 func FromSlash(inputPath, inputOS string) string {