diff --git a/src/lib-storage/index/index-mail.c b/src/lib-storage/index/index-mail.c
index bd70e05195..2e546f628e 100644
--- a/src/lib-storage/index/index-mail.c
+++ b/src/lib-storage/index/index-mail.c
@@ -814,8 +814,7 @@ index_mail_body_parsed_cache_bodystructure(struct index_mail *mail,
 	}
 }
 
-static bool
-index_mail_want_cache(struct index_mail *mail, enum index_cache_field field)
+bool index_mail_want_cache(struct index_mail *mail, enum index_cache_field field)
 {
 	struct mail *_mail = &mail->mail.mail;
 	enum mail_fetch_field fetch_field;
diff --git a/src/lib-storage/index/index-mail.h b/src/lib-storage/index/index-mail.h
index c1e9c2de1a..9dc652cdcf 100644
--- a/src/lib-storage/index/index-mail.h
+++ b/src/lib-storage/index/index-mail.h
@@ -256,6 +256,7 @@ bool index_mail_get_cached_bodystructure(struct index_mail *mail,
 					 const char **value_r);
 const uint32_t *index_mail_get_vsize_extension(struct mail *_mail);
 
+bool index_mail_want_cache(struct index_mail *mail, enum index_cache_field field);
 void index_mail_cache_add(struct index_mail *mail, enum index_cache_field field,
 			  const void *data, size_t data_size);
 void index_mail_cache_add_idx(struct index_mail *mail, unsigned int field_idx,