diff --git a/lib/download.c b/lib/download.c
index 9098b9af..94e5ec3c 100644
--- a/lib/download.c
+++ b/lib/download.c
@@ -104,6 +104,9 @@ xbps_fetch_file(const char *uri,
 	int fd = -1, rv = 0;
 	bool restart = false;
 
+	assert(uri != NULL);
+	assert(outputdir != NULL);
+
 	fetchLastErrCode = 0;
 	fetchTimeout = 30; /* 30 seconds of timeout */
 
diff --git a/lib/humanize_number.c b/lib/humanize_number.c
index 0689215a..9b22d954 100644
--- a/lib/humanize_number.c
+++ b/lib/humanize_number.c
@@ -156,6 +156,8 @@ humanize_number(char *buf, size_t len, int64_t bytes,
 int
 xbps_humanize_number(char *buf, int64_t bytes)
 {
+	assert(buf != NULL);
+
 	return humanize_number(buf, 6, bytes, "B",
 	    HN_AUTOSCALE, HN_DECIMAL|HN_NOSPACE);
 }
diff --git a/lib/package_config_files.c b/lib/package_config_files.c
index 9902cb16..b22ba9aa 100644
--- a/lib/package_config_files.c
+++ b/lib/package_config_files.c
@@ -92,7 +92,9 @@ xbps_entry_install_conf_file(prop_dictionary_t filesd,
 
 	assert(filesd != NULL);
 	assert(entry != NULL);
+	assert(entry_pname != NULL);
 	assert(pkgname != NULL);
+	assert(version != NULL);
 
 	iter = xbps_get_array_iter_from_dict(filesd, "conf_files");
 	if (iter == NULL)
diff --git a/lib/package_remove_obsoletes.c b/lib/package_remove_obsoletes.c
index 298d6e39..8508a799 100644
--- a/lib/package_remove_obsoletes.c
+++ b/lib/package_remove_obsoletes.c
@@ -49,6 +49,9 @@ xbps_remove_obsoletes(prop_dictionary_t oldd, prop_dictionary_t newd)
 	int rv = 0;
 	bool found, dodirs = false, dolinks = false;
 
+	assert(oldd != NULL);
+	assert(newd != NULL);
+
 again:
 	iter = xbps_get_array_iter_from_dict(oldd, array_str);
 	if (iter == NULL)
diff --git a/lib/package_requiredby.c b/lib/package_requiredby.c
index e2faceb8..6f3694df 100644
--- a/lib/package_requiredby.c
+++ b/lib/package_requiredby.c
@@ -129,6 +129,8 @@ xbps_requiredby_pkg_remove(const char *pkgname)
 	char *plist;
 	int rv = 0;
 
+	assert(pkgname != NULL);
+
 	plist = xbps_xasprintf("%s/%s/%s", xbps_get_rootdir(),
 	    XBPS_META_PATH, XBPS_REGPKGDB);
 	if (plist == NULL)
@@ -169,6 +171,9 @@ xbps_requiredby_pkg_add(prop_array_t regar, prop_dictionary_t pkg)
 	char *rdepname;
 	int rv = 0;
 
+	assert(regar != NULL);
+	assert(pkg != NULL);
+
 	prop_dictionary_get_cstring_nocopy(pkg, "pkgver", &pkgver);
 	rdeps = prop_dictionary_get(pkg, "run_depends");
 	if (rdeps == NULL || prop_array_count(rdeps) == 0)
diff --git a/lib/package_state.c b/lib/package_state.c
index bbfd5413..cb90b3ad 100644
--- a/lib/package_state.c
+++ b/lib/package_state.c
@@ -59,6 +59,7 @@ set_new_state(prop_dictionary_t dict, pkg_state_t state)
 	const struct state *stp;
 	const char *pkgname;
 
+	assert(dict != NULL);
 
 	for (stp = states; stp->string != NULL; stp++)
 		if (state == stp->number)
@@ -102,6 +103,7 @@ xbps_get_pkg_state_installed(const char *pkgname, pkg_state_t *state)
 	prop_dictionary_t pkgd;
 
 	assert(pkgname != NULL);
+	assert(state != NULL);
 
 	pkgd = xbps_find_pkg_dict_installed(pkgname, false);
 	if (pkgd == NULL)
@@ -119,6 +121,7 @@ int
 xbps_get_pkg_state_dictionary(prop_dictionary_t dict, pkg_state_t *state)
 {
 	assert(dict != NULL);
+	assert(state != NULL);
 
 	if ((*state = get_state(dict)) == 0)
 		return EINVAL;
@@ -143,6 +146,8 @@ xbps_set_pkg_state_installed(const char *pkgname, pkg_state_t state)
 	int rv = 0;
 	bool newpkg = false;
 
+	assert(pkgname != NULL);
+
 	plist = xbps_xasprintf("%s/%s/%s", xbps_get_rootdir(),
 	    XBPS_META_PATH, XBPS_REGPKGDB);
 	if (plist == NULL)
diff --git a/lib/plist.c b/lib/plist.c
index 7b8dd3cb..6f58e12c 100644
--- a/lib/plist.c
+++ b/lib/plist.c
@@ -200,6 +200,8 @@ xbps_find_pkg_dict_installed(const char *str, bool bypattern)
 	prop_dictionary_t d, pkgd, rpkgd = NULL;
 	pkg_state_t state = 0;
 
+	assert(str != NULL);
+
 	if ((d = xbps_regpkgdb_dictionary_get()) == NULL)
 		return NULL;
 
@@ -489,6 +491,8 @@ _xbps_uncompress_plist_data(char *xml, size_t len)
 	ssize_t totalsize = 0;
 	int rv = 0;
 
+	assert(xml != NULL);
+
 	/* Decompress the mmap'ed buffer with zlib */
 	strm.zalloc = Z_NULL;
 	strm.zfree = Z_NULL;
diff --git a/lib/repository_findpkg.c b/lib/repository_findpkg.c
index 1029ff58..4c0ebfe3 100644
--- a/lib/repository_findpkg.c
+++ b/lib/repository_findpkg.c
@@ -59,6 +59,8 @@ set_pkg_state(prop_dictionary_t pkgd, const char *pkgname)
 	pkg_state_t state = 0;
 	int rv = 0;
 
+	assert(pkgd != NULL);
+
 	rv = xbps_set_pkg_state_dictionary(pkgd, XBPS_PKG_STATE_NOT_INSTALLED);
 	if (rv != 0)
 		return rv;
diff --git a/lib/repository_plist.c b/lib/repository_plist.c
index 82201c02..e9484b2b 100644
--- a/lib/repository_plist.c
+++ b/lib/repository_plist.c
@@ -152,6 +152,9 @@ xbps_repository_get_pkg_plist_dict_from_url(const char *url, const char *plistf)
 	const char *curpath, *comptype;
 	int i = 0;
 
+	assert(url != NULL);
+	assert(plistf != NULL);
+
 	if ((a = open_archive(url)) == NULL)
 		return NULL;
 
@@ -198,6 +201,9 @@ xbps_repository_get_pkg_plist_dict(const char *pkgname, const char *plistf)
 	char *url;
 	int rv = 0;
 
+	assert(pkgname != NULL);
+	assert(plistf != NULL);
+
 	if ((rv = xbps_repository_pool_init()) != 0) {
 		errno = rv;
 		return NULL;
diff --git a/lib/repository_pool.c b/lib/repository_pool.c
index b3a4e404..39731132 100644
--- a/lib/repository_pool.c
+++ b/lib/repository_pool.c
@@ -217,6 +217,8 @@ xbps_repository_pool_foreach(
 	int rv = 0;
 	bool done = false;
 
+	assert(fn != NULL);
+
 	if (!repolist_initialized)
 		return EINVAL;
 
diff --git a/lib/repository_sync_index.c b/lib/repository_sync_index.c
index 0a253384..eb78c81b 100644
--- a/lib/repository_sync_index.c
+++ b/lib/repository_sync_index.c
@@ -95,6 +95,7 @@ xbps_repository_sync_pkg_index(const char *uri,
 	int rv = 0;
 	bool only_sync = false;
 
+	assert(uri != NULL);
 	tmp_metafile = rpidx = lrepodir = lrepofile = NULL;
 
 	if (uname(&un) == -1)
diff --git a/lib/util.c b/lib/util.c
index b4061c35..99d0b182 100644
--- a/lib/util.c
+++ b/lib/util.c
@@ -78,6 +78,8 @@ xbps_get_file_hash(const char *file)
 	int fd;
 	bool need_guard = false;
 
+	assert(file != NULL);
+
 	if ((fd = open(file, O_RDONLY)) == -1) {
 		free(buf);
 		return NULL;
@@ -126,6 +128,9 @@ xbps_check_file_hash(const char *file, const char *sha256)
 {
 	char *res;
 
+	assert(file != NULL);
+	assert(sha256 != NULL);
+
 	res = xbps_get_file_hash(file);
 	if (res == NULL)
 		return errno;
@@ -342,6 +347,8 @@ get_pkg_index_remote_plist(const char *uri)
 {
 	char *uri_fixed, *repodir;
 
+	assert(uri != NULL);
+
 	uri_fixed = xbps_get_remote_repo_string(uri);
 	if (uri_fixed == NULL)
 		return NULL;
@@ -379,6 +386,9 @@ xbps_get_binpkg_repo_uri(prop_dictionary_t pkg_repod, const char *repoloc)
 	const char *filen, *arch, *cdir;
 	char *lbinpkg = NULL;
 
+	assert(pkg_repod != NULL);
+	assert(repoloc != NULL);
+
 	if (!prop_dictionary_get_cstring_nocopy(pkg_repod,
 	    "filename", &filen))
 		return NULL;
@@ -413,6 +423,7 @@ xbps_pkg_has_rundeps(prop_dictionary_t pkg)
 	prop_array_t array;
 
 	assert(pkg != NULL);
+
 	array = prop_dictionary_get(pkg, "run_depends");
 	if (array && prop_array_count(array) > 0)
 		return true;