lib-storage: Add asserts to make sure mailbox_header_lookup_ctx is us…

…ed correctly.

src/lib-storage/index/index-mail-headers.c

@@ -862,9 +862,6 @@ int index_mail_get_header_stream(struct mail *_mail,
 	struct istream *input;
 	string_t *dest;
 
-	i_assert(headers->count > 0);
-	i_assert(headers->box == _mail->box);
-
 	if (mail->data.save_bodystructure_header) {
 		/* we have to parse the header. */
 		const char *reason =

src/lib-storage/mail-storage.c

@@ -1803,6 +1803,8 @@ mailbox_search_init(struct mailbox_transaction_context *t,
 		    enum mail_fetch_field wanted_fields,
 		    struct mailbox_header_lookup_ctx *wanted_headers)
 {
+	i_assert(wanted_headers == NULL || wanted_headers->box == t->box);
+
 	mail_search_args_ref(args);
 	if (!args->simplified)
 		mail_search_args_simplify(args);

src/lib-storage/mail.c

@@ -19,6 +19,8 @@ struct mail *mail_alloc(struct mailbox_transaction_context *t,
 {
 	struct mail *mail;
 
+	i_assert(wanted_headers == NULL || wanted_headers->box == t->box);
+
 	T_BEGIN {
 		mail = t->box->v.mail_alloc(t, wanted_fields, wanted_headers);
 		hook_mail_allocated(mail);
@@ -73,6 +75,8 @@ void mail_add_temp_wanted_fields(struct mail *mail,
 {
 	struct mail_private *p = (struct mail_private *)mail;
 
+	i_assert(headers == NULL || headers->box == mail->box);
+
 	p->v.add_temp_wanted_fields(mail, fields, headers);
 }
 
@@ -232,6 +236,9 @@ int mail_get_header_stream(struct mail *mail,
 	struct mail_private *p = (struct mail_private *)mail;
 	int ret;
 
+	i_assert(headers->count > 0);
+	i_assert(headers->box == mail->box);
+
 	T_BEGIN {
 		ret = p->v.get_header_stream(mail, headers, stream_r);
 	} T_END;