Code review comment for lp:~julian-edwards/maas/acl-for-dns-trigger-rewrite

It looks to me as if test_writes_dns_when_network_edited should be called test_writes_dns_when_network_created. Why does it go through the form?

I still don't like signals for this kind of thing. Do we know what we'll be doing during network auto-discovery? Will we implicitly be firing off a bunch of DNS server restarts concurrently, which may then get confused and break? It would make more sense to me to set some kind of “dirty” flag on DNS, and process that separately.

Also, consider triggering the signal only on specific field changes. Updating the description on a network, or saving it without changes, or perhaps updating some future field that may see routine changes, probably needn't activate the whole DNS machinery.