Merge lp:~martin-hilton/juju-deployer/speed-up-inheritance into lp:juju-deployer

[Martin Hilton]

Stop extending the parents list whilst iterating over it when resolving inheritance.

Speed up inheritance by not extending the parents list at the same time as iterating over it.

[Francesco Banconi (frankban)]

Looks good to me.

review: Approve

[Roger Peppe (rogpeppe)]

LGTM except that it really should have a test (ideally one that goes
into an infinite loop before this fix).

Also, given that it's almost certainly an infinite loop (correctness)
problem, the change description seems inaccurate.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[Tom Haddon (mthaddon)]

Abstaining since this is so old

review: Abstain

Unmerged revisions

211. By Martin Hilton on 2017-03-17

Stop extending the parents list whilst iterating over it when resolving inheritance.

=== modified file 'deployer/config.py'
--- deployer/config.py	2016-07-12 02:29:52 +0000
+++ deployer/config.py	2017-03-17 10:02:42 +0000
@@ -109,7 +109,8 @@
     def _resolve_inherited(self, deploy_data):
         if 'inherits' not in deploy_data:
             return deploy_data
-        inherits = parents = self._inherits(deploy_data)
+        parents = self._inherits(deploy_data)
+        inherits = list(parents)
         for parent_name in parents:
             parent = self.get(parent_name)
             inherits.extend(self._inherits(parent.data))