lib: fix memory leak in conflict string generation

Author: Duncaen

lib/transaction_check_conflicts.c

@@ -101,8 +101,12 @@ pkg_conflicts_trans(struct xbps_handle *xhp, xbps_array_t array,
 			buf = xbps_xasprintf("CONFLICT: %s with "
 			    "installed pkg %s (matched by %s)",
 			    repopkgver, pkgver, cfpkg);
-			if (!xbps_array_add_cstring(trans_cflicts, buf))
+			if (!buf)
+				return xbps_error_oom();
+			if (!xbps_array_add_cstring_nocopy(trans_cflicts, buf)) {
+				free(buf);
 				return xbps_error_oom();
+			}
 			continue;
 		}
 		/*
@@ -129,8 +133,10 @@ pkg_conflicts_trans(struct xbps_handle *xhp, xbps_array_t array,
 			   repopkgver, pkgver, cfpkg);
 			if (!buf)
 				return xbps_error_oom();
-			if (!xbps_array_add_cstring_nocopy(trans_cflicts, buf))
+			if (!xbps_array_add_cstring_nocopy(trans_cflicts, buf)) {
+				free(buf);
 				return xbps_error_oom();
+			}
 			continue;
 		}
 	}
@@ -192,8 +198,10 @@ pkgdb_conflicts_cb(struct xbps_handle *xhp, xbps_object_t obj,
 			   repopkgver, pkgver, cfpkg);
 			if (!buf)
 				return xbps_error_oom();
-			if (!xbps_array_add_cstring_nocopy(trans_cflicts, buf))
+			if (!xbps_array_add_cstring_nocopy(trans_cflicts, buf)) {
+				free(buf);
 				return xbps_error_oom();
+			}
 			continue;
 		}
 	}