allow for custom optimization strategies

[bhearsum]

At the moment, taskgraph hardcodes the OptimizationSchema with no way to override it. This means that even though you can register new optimization strategies, the task.py transform will not accept them.

It looks like Gecko added support for this many years ago, but it never made it upstream.

[ahal]

I think rather than copy Gecko here, I'd rather the schema be provided as an argument to the @register_strategy decorator. That way the schema definition lives next to the thing that requires it and we don't need to call extra functions in the registration.

[ahal]

See the group_by decorator for an example of this:

taskgraph/src/taskgraph/util/dependencies.py

Line 38 in 931ab6f

@group_by("attribute", schema=Schema(str))

[bhearsum]

I think rather than copy Gecko here, I'd rather the schema be provided as an argument to the @register_strategy decorator. That way the schema definition lives next to the thing that requires it and we don't need to call extra functions in the registration.

Sounds very reasonable to me!