Previously it was either all-locked or all-not-locked. Now you can
simulate having the same shared storage opened by multiple managers,
only one of which has the lock.
The Futureproof<T> type lets you serialize and deserialize types whose
representations might change (most useful for enums that might grow
additional variants). It uses #[serde(untagged)] to accomplish this.
This gets used in order to make the `disabled` field of `Guard` more
robust against future guard disablement reasons being added.
A test was also added to verify correct behaviour of the new type.
As per arti#175, we'd like to be able to handle newer Arti versions
storing additional state in the persisted state files, without dropping
this data on the floor when we write out changes to these files.
Use the #[serde(flatten)] mechanism to achieve this, by adding catch-all
HashMap<String, JsonValue> fields to all structs that are at risk of
this happening to them.
The limitations with toml seemed to be reaching a head, and I wasn't
able to refactor the guardmgr code enough to actually have its state
be serializable as toml. Json's limitations are much narrower.
Nick Mathewson
eta
Jani Monoses
Trinity Pointard
Daniel Eades