do not export private members in an interface

Author: Jguer

.devcontainer/Dockerfile

@@ -2,7 +2,9 @@
 FROM docker.io/jguer/yay-builder
 
 # Install extra packages (pacman-contrib and fish)
-RUN sudo pacman -Syu --noconfirm pacman-contrib fish git-delta openssh bat go
+# Note: Using -Sy instead of -Syu to avoid full system upgrade which fails
+# due to read-only /etc/resolv.conf and /etc/hosts during Docker build
+RUN sudo pacman -Sy --noconfirm pacman-contrib fish git-delta openssh bat go
 
 # Set passwordless sudo for the docker user
 RUN echo "docker ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/docker

interfaces.go

@@ -77,9 +77,6 @@ type IPackage interface {
 	SyncNewVersion(l IDBList) IPackage
 
 	Type() string
-
-	// Get the underlying alpm pkg type
-	getPmpkg() *C.alpm_pkg_t
 }
 
 // IPackageList exports the alpm.PackageList symbols.

package.go

@@ -298,10 +298,6 @@ func (pkg *Package) Type() string {
 	return "alpm"
 }
 
-func (pkg *Package) getPmpkg() *C.alpm_pkg_t {
-	return pkg.pmpkg
-}
-
 // SortBySize returns a PackageList sorted by size.
 func (l PackageList) SortBySize() IPackageList {
 	pkgList := (*C.struct__alpm_list_t)(unsafe.Pointer(l.list))

trans.go

@@ -12,9 +12,13 @@ package alpm
 import "C"
 
 import (
+	"fmt"
 	"unsafe"
 )
 
+// ErrInvalidPackageType is returned when an invalid package type is used.
+var ErrInvalidPackageType = fmt.Errorf("invalid Package type")
+
 func (h *Handle) TransInit(flags TransFlag) error {
 	ret := C.alpm_trans_init(h.ptr, C.int(flags))
 	if ret != 0 {
@@ -82,7 +86,12 @@ func (h *Handle) TransGetFlags() (TransFlag, error) {
 }
 
 func (h *Handle) AddPkg(pkg IPackage) error {
-	ret := C.alpm_add_pkg(h.ptr, pkg.getPmpkg())
+	aPkg, ok := pkg.(*Package)
+	if !ok {
+		return ErrInvalidPackageType
+	}
+
+	ret := C.alpm_add_pkg(h.ptr, aPkg.pmpkg)
 	if ret != 0 {
 		return h.LastError()
 	}
@@ -91,7 +100,11 @@ func (h *Handle) AddPkg(pkg IPackage) error {
 }
 
 func (h *Handle) RemovePkg(pkg IPackage) error {
-	ret := C.alpm_remove_pkg(h.ptr, pkg.getPmpkg())
+	aPkg, ok := pkg.(*Package)
+	if !ok {
+		return ErrInvalidPackageType
+	}
+	ret := C.alpm_remove_pkg(h.ptr, aPkg.pmpkg)
 	if ret != 0 {
 		return h.LastError()
 	}