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Scala 3 Migration: Report from the field

blog.pierre-ricadat.com

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Re: Scala 3 Migration: Report from the field

#11

Post by dkarl »

dtech wrote: post #7

I left the Scala ecosystems (mostly) a year or 4 ago, right around the release of Scala 3. It's a shame that the compatibility and tooling situation doesn't seem to have improved much since then. The Scala devs always said they wanted to avoid a Python 2->3 situation, but it seemed like they didn't quite achieve that.

I think you should read this report. They made heavy use of many advanced features of Scala 2. Few codebases look like this (and very, very few need to) yet they were able to do it.

Moreover, they didn't need to do it. What makes it similar to the Python 2 -> 3 situation is the lack of urgency to migrate, because nobody suffers for not migrating. That's a good thing.

Re: Scala 3 Migration: Report from the field

#12

Post by kokada »

dtech wrote: post #7

I left the Scala ecosystems (mostly) a year or 4 ago, right around the release of Scala 3. It's a shame that the compatibility and tooling situation doesn't seem to have improved much since then. The Scala devs always said they wanted to avoid a Python 2->3 situation, but it seemed like they didn't quite achieve that.

I don't know, if anything the Scala situation seems much worse than the Python situation. The language looks completely different and there is no easy migration path (not that Python had one, but at least the language was almost the same and you could with some effort write code that worked in both versions).

We are in Scala 2.13 and while there are talks about migrating there is no actual plan. Looking at this blog post the situation seems to be more dire than I initially expected. I think we will only end up migrating when the situation becomes unsustainable (libraries stop supporting Scala 2).

Re: Scala 3 Migration: Report from the field

#14

Post by adamwk »

kokada wrote: post #12
dtech wrote: post #7

I left the Scala ecosystems (mostly) a year or 4 ago, right around the release of Scala 3. It's a shame that the compatibility and tooling situation doesn't seem to have improved much since then. The Scala devs always said they wanted to avoid a Python 2->3 situation, but it seemed like they didn't quite achieve that.

I don't know, if anything the Scala situation seems much worse than the Python situation. The language looks completely different and there is no easy migration path (not that Python had one, but at least the language was almost the same and you could with some effort write code that worked in both versions). We are in Scala 2.13 and while there are talks about migrating there is no actual plan. Looking at this blog…

Odersky forcing through major syntax changes for Scala 3 was such an unforced error. It's baffling add new syntax on top of major semantic changes to the type system.

Re: Scala 3 Migration: Report from the field

#15

Post by aiono »

slavomirvojacek wrote: post #13

I am wondering whether with GenAI, migrations like this one will be less and less painful, and therefore more people will be able to migrate to newer technologies/versions sooner and quicker.

Why use GenAI for this use case? Instead you can write transformers from one syntax to another syntax that will not hallucinate and work correctly every time. The conversion is well-defined.

Re: Scala 3 Migration: Report from the field

#16

Post by nsonha »

aiono wrote: post #15
slavomirvojacek wrote: post #13

I am wondering whether with GenAI, migrations like this one will be less and less painful, and therefore more people will be able to migrate to newer technologies/versions sooner and quicker.

Why use GenAI for this use case? Instead you can write transformers from one syntax to another syntax that will not hallucinate and work correctly every time. The conversion is well-defined.

Or use GenAI to write the codemod :)

Re: Scala 3 Migration: Report from the field

#18

Post by theLiminator »

Back when I used to use Scala, the biggest PITA was how every minor version bump you'd run into binary version incompatibilities that you'd only run into at runtime. Has that situation changed?

I've always felt that Scala the language was always pretty nice, but Scala the ecosystem/tooling was moderately painful to work with. It was getting better over time, but they lost all the momentum they had.

Re: Scala 3 Migration: Report from the field

#19

Post by philipkglass »

theLiminator wrote: post #18

Back when I used to use Scala, the biggest PITA was how every minor version bump you'd run into binary version incompatibilities that you'd only run into at runtime. Has that situation changed? I've always felt that Scala the language was always pretty nice, but Scala the ecosystem/tooling was moderately painful to work with. It was getting better over time, but they lost all the momentum they had.

Yes, that's one of the big improvements in Scala 3.

https://docs.scala-lang.org/overviews/core/binary-compatibil...

For Scala 3, the minor version is the second number in a version, e.g., 2 in v3.2.1. The third number is the patch version. The major version is always 3.

Scala 3 guarantees both backward and forward compatibility across patch releases within a single minor release (enforcing forward binary compatibility is helpful to maintain source compatibility). In particular, this applies within an entire Long-Term-Support (LTS) series such as Scala 3.3.x.

Scala 3 also guarantees backward compatibility across minor releases in the entire 3.x series, but not forward compatibility. This means that libraries compiled with any Scala 3.x version can be used in projects compiled with any Scala 3.y version with y >= x.

In addition, Scala 3.x provides backward binary compatibility with respect to Scala 2.13.y. Libraries compiled with Scala 2.13.y can be used in projects using Scala 3.x. This policy does not apply to experimental Scala 2 features, which notably includes macros.

Re: Scala 3 Migration: Report from the field

#20

Post by dionian »

theLiminator wrote: post #18

Back when I used to use Scala, the biggest PITA was how every minor version bump you'd run into binary version incompatibilities that you'd only run into at runtime. Has that situation changed? I've always felt that Scala the language was always pretty nice, but Scala the ecosystem/tooling was moderately painful to work with. It was getting better over time, but they lost all the momentum they had.

yes, and you can even use 2.13 binaries in 3
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