Originally reported here - https://marc.info/?l=openbsd-ports&m=159731598419071&w=2
OpenBSD's printf functions have a (mostly annoying but occasionally useful) feature where they generate a syslog entry if printf %s format is called with a null pointer.
It is tripped in lmtp/lda deliveries with 2.3.11.3:
lmtp: vfprintf %s NULL in "Cache %s: " dovecot-lda: vfprintf %s NULL in "Cache %s: "
src/lib-index/mail-cache.c: .. 557 struct mail_cache * 558 mail_cache_open_or_create_path(struct mail_index *index, const char *path) 559 { .. 565 cache->filepath = i_strdup(path); .. 572 event_set_append_log_prefix(cache->event, 573 t_strdup_printf("Cache %s: ", cache->filepath); ..
Seems something is wrong to have this function called with no cache path?