difflicious and diffx

[ghostbuster91]

Hi,

I tried reaching you out on twitter but the tweet must've got lost among others. I always thought that the way you designed difflicious internals is superior to what I did in diffix, but up until that moment I was able to implement everything I needed in diffx.
Recent bug issue(softwaremill/diffx#418) pointed out some flaws in the diffx that cannot be fully fixed without major rewrite of internals. Of course, I could make that rewrite but that would mean doing basically the same thing what you did in difflicious. I don't really see a point in fixing diffx that way, when there is already a better version of it implemented :) While implementing diffx and later maintaining it was a great journey for me, I think that objectively the best I can do now is to deprecate it and redirect users to your library. However, there are some users of diffx out there and I would like to do it right, and provide a smooth transition for them.

First, I would like to make sure that you are planning to maintain difflicious and you have a capacity to do that. These days my capacity is fairly limited by other projects but I will be happy to help if you need any help.
Second, I am considering writing a scalafix rule to ease the migration. I guess rewriting imports and class names would cover most of the cases. Do you think it is a good idea?
Third, difflicious doesn't support automatic derivation. I understand reasoning behind that decision. I never use auto derivation in my own projects. Still, there are some people that do, and it is a nice feature especially when prototyping/ trying out new things. Would you consider adding it? (maybe it could be done as a separate module?)

[jatcwang]

Hi @ghostbuster91 thanks for the kind words. Yeah I did not receive any message from you on Twitter..definitely had similar things happen before 🤔

• I do plan to maintain this lib and still got some big improvements I'm hoping to implement, but time is limited these days and whatever I have I try to push Doobie a little bit closer to 1.0. Help will be much appreciated and I'm more than happy to add you as a maintainer :)
• I think the lack of auto-derviation will be a blocker for a useful scalafix rule. Happy to make auto-derivation available under a separate import (like Circe) as I have wished for it a few times while debugging legacy tests using classic assertions ;)

[ghostbuster91]

Understood and thank you. I won't have much time before December but after that I can try contributing the auto-derivation. It seems that we have some vague plan of moving forward. So to sum up:

• add the auto-derivation to difflicious
• put diffx into maintenance mode
• scalafix rule for migration from diffx
• test the migration and see if there is still anything missing that should be added to difflicious
• final deprecation of diffix and redirection of users to difflicious

Let me know if you think that something is missing or should be done in different order.

[jatcwang]

Yep sounds good to me thanks!