on cycles

diff --git a/doc/design/passthrough_proxy.mdwn b/doc/design/passthrough_proxy.mdwn
index 6b8d5e6db872e83a71106f3745210667405b3214..3332c77ac0dcb900ebb9b3b2d15a69a0c8d7a10e 100644 (file)
--- a/doc/design/passthrough_proxy.mdwn
+++ b/doc/design/passthrough_proxy.mdwn
@@ -282,6 +282,23 @@ in front of the proxy.
 
 ## cycles
 
+A repo can advertise that it proxies for a repo which has the same uuid as
+itself. Or there can be a larger cycle involving a proxy that proxies to a
+proxy, etc.
+
+Since the proxied repo uuid is communicated to git-annex-shell via 
+--uuid, a repo that advertises proxying for itself will be connected to
+with its own uuid. No proxying is done in this case. Same happens with a
+larger cycle.
+
+Instantiating remotes needs to identity cycles and break them. Otherwise
+it would construct an infinite number of proxied remotes with names
+like "foo-foo-foo-foo-..." or "foo-bar-foo-bar-..."
+
+Once `git-annex copy --to proxy` is implemented, and the proxy decides
+where to send content that is being sent directly to it, cycles will
+become an issue with that as well.
+
 What if repo A is a proxy and has repo B as a remote. Meanwhile, repo B is
 a proxy and has repo A as a remote?
 
@@ -295,7 +312,7 @@ remote that is not part of a cycle, they could deposit the upload there and
 the upload still succeed. Otherwise the upload would fail, which is
 probably the best that can be done with such a broken configuration.
 
-So, it seems like proxies will need to take transfer locks for uploads,
+So, it seems like proxies would need to take transfer locks for uploads,
 even though the content is being proxied to elsewhere.
 
 Dropping could have similar cycles with content presence locking, which

diff --git a/doc/todo/git-annex_proxies.mdwn b/doc/todo/git-annex_proxies.mdwn
index 68213670b4ff218508ee6e1250641646a9e78725..9966e0700c0def7246805d5725e9dd068cb924b4 100644 (file)
--- a/doc/todo/git-annex_proxies.mdwn
+++ b/doc/todo/git-annex_proxies.mdwn
@@ -44,6 +44,13 @@ For June's work on [[design/passthrough_proxy]], implementation plan:
 * Consider getting instantiated remotes into git remote list.
   See design.
 
+* Support proxies-of-proxies better, eg foo-bar-baz.
+  Currently, it does work, but have to run `git-annex updateproxy`
+  on foo in order for it to notice the bar-baz proxied remote exists,
+  and record it as foo-bar-baz. Make it skip recording proxies of
+  proxies like that, and instead automatically generate those from the log.
+  (With cycle prevention there of course.)
+
 * Cycle prevention. See design.
 
 * Make `git-annex copy --from $proxy` pick a node that contains each