use path.Join for cross-platform abs paths

Signed-off-by: Praful <[email protected]>

Author: Horiodino

pkg/mcp/toolset/toolset.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"path"
 	"path/filepath"
 	"slices"
 	"strings"
@@ -107,7 +108,7 @@ func (ts *ToolSet) TranslateHostPath(hostPath string) (guestPath, warnings strin
 	if hostPath == "" {
 		return "", "", errors.New("path is empty")
 	}
-	if !filepath.IsAbs(hostPath) {
+	if !filepath.IsAbs(hostPath) && !strings.HasPrefix(hostPath, "/") {
 		return "", "", fmt.Errorf("expected an absolute path, got a relative path: %q", hostPath)
 	}
 
@@ -130,7 +131,8 @@ func (ts *ToolSet) translateToGuestPath(hostPath string) (string, bool) {
 
 		rel, err := filepath.Rel(location, cleanPath)
 		if err == nil && !strings.HasPrefix(rel, "..") && rel != ".." {
-			guestPath := filepath.Join(*mount.MountPoint, rel)
+			rel = filepath.ToSlash(rel)
+			guestPath := path.Join(*mount.MountPoint, rel)
 			return guestPath, true
 		}
 	}

pkg/mcp/toolset/toolset_test.go

@@ -88,6 +88,38 @@ func TestTranslateHostPath(t *testing.T) {
 			wantWarnings:  false,
 			wantErr:       false,
 		},
+		{
+			name:     "relative path should error",
+			hostPath: "relative/path",
+			toolSet: ToolSet{
+				inst: &limatype.Instance{
+					Config: &limatype.LimaYAML{
+						Mounts: []limatype.Mount{
+							{Location: "/home/user", MountPoint: &mountPoint1},
+						},
+					},
+				},
+			},
+			wantGuestPath: "",
+			wantWarnings:  false,
+			wantErr:       true,
+		},
+		{
+			name:     "empty path should error",
+			hostPath: "",
+			toolSet: ToolSet{
+				inst: &limatype.Instance{
+					Config: &limatype.LimaYAML{
+						Mounts: []limatype.Mount{
+							{Location: "/home/user", MountPoint: &mountPoint1},
+						},
+					},
+				},
+			},
+			wantGuestPath: "",
+			wantWarnings:  false,
+			wantErr:       true,
+		},
 	}
 
 	for _, test := range tests {