Move skipping of duplicate sync/remove targets into libalpm

sync:
As pointed out by Andrew Gregory there could be an error when adding
duplicates if they are two separate packages with the same name. Add a
check in alpm_add_pkg() to test whether the duplicate is actually the
same package, and if so, log a debug message and return success to skip
the package. If the duplicate is a different package return
ALPM_ERR_TRANS_DUP_TARGET and treat that error just like any other error
in pacman.

remove:
Change alpm_remove_pkg() to just log a debug message and return success
to skip duplicates. Remove the handling of ALPM_ERR_TRANS_DUP_TARGET in
pacman.

Also fixes FS#49377.

Suggested-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Michael Straube <michael.straube@posteo.de>
Signed-off-by: Allan McRae <allan@archlinux.org>

2 files changed, 9 insertions, 2 deletions

diff --git a/lib/libalpm/add.c b/lib/libalpm/add.c
index e415bb17..c39f9ecf 100644
--- a/lib/libalpm/add.c
+++ b/lib/libalpm/add.c
@@ -53,6 +53,7 @@ int SYMEXPORT alpm_add_pkg(alpm_handle_t *handle, alpm_pkg_t *pkg)
 	const char *pkgname, *pkgver;
 	alpm_trans_t *trans;
 	alpm_pkg_t *local;
+	alpm_pkg_t *dup;
 
 	/* Sanity checks */
 	CHECK_HANDLE(handle, return -1);
@@ -70,7 +71,12 @@ int SYMEXPORT alpm_add_pkg(alpm_handle_t *handle, alpm_pkg_t *pkg)
 
 	_alpm_log(handle, ALPM_LOG_DEBUG, "adding package '%s'\n", pkgname);
 
-	if(alpm_pkg_find(trans->add, pkgname)) {
+	if((dup = alpm_pkg_find(trans->add, pkgname))) {
+		if(dup == pkg) {
+			_alpm_log(handle, ALPM_LOG_DEBUG, "skipping duplicate target: %s\n", pkgname);
+			return 0;
+		}
+		/* error for separate packages with the same name */
 		RET_ERR(handle, ALPM_ERR_TRANS_DUP_TARGET, -1);
 	}
 
diff --git a/lib/libalpm/remove.c b/lib/libalpm/remove.c
index 78ca5be7..50de4649 100644
--- a/lib/libalpm/remove.c
+++ b/lib/libalpm/remove.c
@@ -74,7 +74,8 @@ int SYMEXPORT alpm_remove_pkg(alpm_handle_t *handle, alpm_pkg_t *pkg)
 	pkgname = pkg->name;
 
 	if(alpm_pkg_find(trans->remove, pkgname)) {
-		RET_ERR(handle, ALPM_ERR_TRANS_DUP_TARGET, -1);
+		_alpm_log(handle, ALPM_LOG_DEBUG, "skipping duplicate target: %s\n", pkgname);
+		return 0;
 	}
 
 	_alpm_log(handle, ALPM_LOG_DEBUG, "adding package %s to the transaction remove list\n",