Lift 4 feedback?

[Matt Farmer]

How has Lift 4 RC1 been treating everyone?

Would we be good to call this final?

[Andreas Joseph Krogh]

We're running this in production and have fo a while, so 👍

 

Keep 🎸!

 

--

Andreas Joseph Krogh

CTO / Partner - Visena AS

Mobile: +47 909 56 963

and...@visena.com

www.visena.com

 

 

På søndag 19. april 2026 kl. 14:38:38, skrev 'Matt Farmer' via Lift <lif...@googlegroups.com>:

How has Lift 4 RC1 been treating everyone?

 

Would we be good to call this final?

 

 

 

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[François ARMAND - Rudder]

We need to remove lift-json first, there is too much incompatibilities in our use cases - we were already migrating away from it, so we "just" need to finish that process.
But don't refrain yourself from calling it a final, we will see once we catch up :)

François ARMAND CTO T: +33 183 62 99 23   M: +33 663 37 60 55

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[Andreas Joseph Krogh]

I'm curious; what do you mean by “remove lift-json first”?

lift-json i already removed. Are you experiancing any difficulties migrating to json4s? If so I'm interested to hear about it.

To view this discussion visit https://groups.google.com/d/msgid/liftweb/a273266a-284b-445e-ac06-241549d3eb37%40rudder.io.
 

[François Armand]

Hello,

When you did the switch from lift-json to json4s, we tried to see how it want for us.

We hit several issues like https://github.com/json4s/json4s/pull/1772 or https://github.com/json4s/json4s/issues/1811
which would have needed substantial changes in our code base.

Since we were already switching from lift-json to zio-json, it wasn't making sense to do work to migrate from lift-json to json4s and then from json4s to zio-json, so we preferred to prioritized finishing our on-going migration before switching to lift 4 rc.

This should be a matter of a couple weeks now.

--
François ARMAND

19 avr. 2026 22:56:59 Andreas Joseph Krogh <and...@visena.com>:

[Andreas Joseph Krogh]

Lucky for us, our json4s-issues where fixed and released in time (https://github.com/json4s/json4s/issues/1811 isn't an issue for us).

We decided to not introduce yet another json-lib as Lift still pulls in json4s to work internally.

To view this discussion visit https://groups.google.com/d/msgid/liftweb/fc075f69-781f-4378-b40f-a6a2778f6b52%40rudder.io.
 

[François ARMAND - Rudder]

So, some report on migrating to 4.0.0-RC1 now that we remove our usage of lift-json : it looks like it works :) 

The only noticeable thing found for now is that I saw a change in behavior in our use of `LiftRules.liftContextRelativePath` 'toString' which used to render the path, and now I need to do `LiftRules.liftContextRelativePath().mkString("/")` - but perhaps I'm just missing some import. In any case, it wasn't hard to workaround. 

I have some question about dependencies though:

- I see that there is still `scala-compiler`. It used to be a dependency of `lift-json` but afaik it is not the case for json4s (https://github.com/json4s/json4s/issues/108). Why it is sill needed ? It's a big and dangerous dependency, if we can get rid of it, it would be awesome

- what about rhino ? Is it still used ? It's not very maintained, and I'm not sure lift still execute server-side JS given all the lift-4 changes. Same as for scala-compiler, if we can get rid of it, it would be a win. 


Awesome work in any case, congrats !



François ARMAND CTO T: +33 183 62 99 23   M: +33 663 37 60 55

On 19/04/2026 14:38, 'Matt Farmer' via Lift wrote:

How has Lift 4 RC1 been treating everyone?

Would we be good to call this final?