Give sensible feedback when a repo has no configured servers

This fixes FS#14899. When running an -Sp operation without servers
configured for a repository, we would segfault, so add an assert to the
backend method returning the first server preventing a null pointer
dereference.

In addition, add a new error code to libalpm that indicates we have no
servers configured for a repository. This makes -Sy and -S <package>
operations fail gracefully and helpfully when a repo is set up with no
servers, as the default mirrorlist in Arch is provided this way.

Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/libalpm/db.c b/lib/libalpm/db.c
index 561967ce..6749ab1e 100644
--- a/lib/libalpm/db.c
+++ b/lib/libalpm/db.c
@@ -232,6 +232,7 @@ const char SYMEXPORT *alpm_db_get_url(const pmdb_t *db)
 	/* Sanity checks */
 	ASSERT(handle != NULL, return(NULL));
 	ASSERT(db != NULL, return(NULL));
+	ASSERT(db->servers != NULL, return(NULL));
 
 	url = (char*)db->servers->data;