swarm: changes taken unjudged, dropped (REFUSALS)

A node refusing changes a peer brought tells it which broke a rule; the
peer judges them itself, and if its rules refuse them too, drops them
with all built on them (its document forked without them, a fresh
actor), quarantining its own writes among them. Wire version 42.

Auth plan M6 (rejoin on taint).

1 files changed, 12 insertions, 1 deletions

diff --git a/docs/access.md b/docs/access.md
index 31efe4e..44c89f3 100644
--- a/docs/access.md
+++ b/docs/access.md
@@ -246,7 +246,18 @@ from then on builds on what was refused, and logs it once. It shows in `GET /pee
 (`refused`, with the change and why), in `/admin/stats` (`sync.refusedPeers`) and on the
 dashboard. A node that only passed a refused change on isn't: the committer is, whoever
 brought it. It lasts until a change of the member's is taken again (it rejoined and
-writes anew), or the epoch changes; forgetting or banning it is the operators'. A change whose
+writes anew), or the epoch changes; forgetting or banning it is the operators'.
+
+A node takes a change the others refuse only if it didn't judge it as they do: under a
+policy it didn't know yet (it receives without judging then), or before the policy
+came. Everything it writes from then on builds on that change, and is refused too. So
+a node refusing changes a peer brought tells it which broke a rule (REFUSALS, at most
+every 30 seconds). The peer doesn't take the word for it: it judges each it holds
+itself, by its rules as they are now. If they refuse one too, it drops it with
+everything built on it, its document becoming what it would be without them, and puts
+its own writes among them in the quarantine (`GET /admin/quarantine`), to be replayed
+or discarded; what it writes from then on goes everywhere. If its rules take the
+change, the two policies disagree, which it logs. A change whose
 dependencies haven't come yet waits for them.
 
 What it doesn't do yet: