[FEATURE] Object Mutability Consistency

[e-lo]

User Story

As a user I'd like to have a consistent expectation about if I am modifying an object in-place or creating a mutated copy.

Status

• [x] Defined
• [x] Planned
• [x] Implemented
• [x] Tested

Context

Right now, there is are public methods in roadway and transit network objects that:

• mutate the object in-place
• return the mutated object
• have an option to do either

This inconsistency in the API has caused lots of confusion and bugs.

Resolution Ideas

Add and implement the following design principle:

• Public methods of the transit and roadway networks should always return a copied, mutated form of the network object

Priority

High

Level of Effort

Low

Project

Is there a funder or project associated with this feature?

Who should be involved?

Implementer: Commenters: Users: Reviewers:

Risk

Will this potentially break anything?

Tests

What are relevant tests or what tests need to be created in order to determine that this issue is complete?

[e-lo]

Update: will test performance of deep copy on a real-size network to evaluate if this is an ok default.

[e-lo]

Performance: Copying the instance of the full bay area network takes a little over than a second.

@lmz @DavidOry thoughts?

[DavidOry]

Well that's encouraging. Perhaps we create another issue to remind us to test this once version 1 is released, but for now move ahead with your original plan?

[e-lo]

Fixed in https://github.com/wsp-sag/network_wrangler/pull/327