Merge pull request #323 from sjrd/report-2023-q4

Add the 2023 Q4 report and the 2024 Q1 roadmap.

Author: sjrd

projects.md

@@ -1,3 +1,3 @@
 ---
-redirect_to: /records/2023-Q4-roadmap.html
+redirect_to: /records/2024-Q1-roadmap.html
 ---

records.md

@@ -14,6 +14,7 @@ Every quarter, the Scala Center publishes an activity report detailing the
 work that has been achieved. You can find the roadmap for the current quarter
 in the [Projects page]({% link projects.md %}).
 
+- [2023, Q4]({% link records/2023-Q4-activity-report.md %})
 - [2023, Q3]({% link records/2023-Q3-activity-report.md %})
 - [2023, Q2]({% link records/2023-Q2-activity-report.md %})
 - [2023, Q1]({% link records/2023-Q1-activity-report.md %})

records/2023-Q4-activity-report.md

@@ -0,0 +1,251 @@
+---
+layout: contact
+title: Scala Center Activity Report for 2023 Q4
+---
+
+Scala Center team:
+Darja Jovanovic, 100%;
+Anatolii Kmetiuk, 100%;
+Adrien Piquerez, 80%;
+Jamie Thompson, 100%;
+Sébastien Doeraene, 80%;
+Guillaume Martres, 20%;
+Valérie Meillaud: 30%.
+VirtusLab team: Jędrzej Rochala, 100%.
+
+## At a Glance
+{: .no_toc}
+
+* Table of Contents
+{:toc}
+
+
+## Language, Compiler, Standard Library
+
+### Maintainance of the Scala 3 Compiler
+
+For Scala 3.
+
+Every month, about 100 new issues are opened on [the Scala 3 repository](https://github.com/lampepfl/dotty/).
+The project welcomes any help it can get in triaging, bug-fixing, PR reviewing, etc.
+
+Our goal is to solve long-standing issues while keeping up with new ones.
+We also aim to get more people involved in working on the compiler to ensure the sustainability of the project.
+
+We contributed PRs for bug fixes in various areas, but would like to highlight one.
+
+Our previous work on [SIP-56, Specification for Match Types](https://docs.scala-lang.org/sips/match-types-spec.html), landed.
+It will be released as part of Scala 3.4.0, which is currently in the Release Candidate phase.
+The new specification and implementation provide a strong basis for future stability of the compiler.
+Feedback from Release Candidates surfaced a few minor issues, which we have addressed.
+We still intend to improve on this topic, notably in the area of error reporting.
+
+### Compile Progress reporting
+
+For Scala 2 and 3.
+
+A key part of the user experience is estimating how long you still have to wait for builds to run.
+Both Metals and IntelliJ can report this information to the user, through a dedicated interface to the compiler.
+Until now this was not supported by Scala 3, but added an integration to the compiler in PR [lampepfl/dotty#18739](https://github.com/lampepfl/dotty/pull/18739).
+
+Metals combined with sbt as a BSP server was not reporting progress from either Scala 2 or 3, so we fixed that in PR [scalameta/metals#5788](https://github.com/scalameta/metals/pull/5788).
+
+### Scala.js maintenance
+
+For Scala 2 and 3.
+
+We released [Scala.js 1.15.0](https://www.scala-js.org/news/2023/12/29/announcing-scalajs-1.15.0/) during this quarter.
+
+The main highlight of this release is that it makes Scala.js ready for [SIP-51, Drop Forwards Binary Compatibility of the Scala 2.13 Standard Library](https://docs.scala-lang.org/sips/drop-stdlib-forwards-bin-compat.html).
+That will allow us to evolve the Scala 2.13.x standard library.
+
+### Improving Performance of the Scala 3 compiler
+
+For Scala 3.
+
+#### Support for pipelined concurrent compilation
+
+Pipelined concurrent builds are a technique for increasing throughput in the context of multi-module projects.
+The concept is that dependent modules can begin compilation "as-soon-as" necessary artifacts for separate compilation can be produced.
+In the Scala compiler, these products can be emitted about 30-40% into the compilation of a single module (even sooner if outline type-checking is used).
+
+Pipelined builds have been implemented in sbt since 1.4, with support in Scala 2.13.
+We have made critical progress towards supporting them also in Scala 3.
+
+In PRs [lampepfl/dotty#19074](https://github.com/lampepfl/dotty/pull/19074) and [lampepfl/dotty#19259](https://github.com/lampepfl/dotty/pull/19259) we stabilised the production of outline signatures in TASTy for Java source programs.
+That is is necessary for pipeline compilation of mixed Java/Scala projects.
+
+In PR [lampepfl/dotty#18880](https://github.com/lampepfl/dotty/pull/18880) we are close to finalising support for the semantics expected by Zinc's model of pipeline compilation, and aim to merge it in Q1 2024.
+
+#### Support for outline compilation
+
+In PR [lampepfl/dotty#19589](https://github.com/lampepfl/dotty/pull/19589) we are experimenting with an outline type checking mode, which builds on top of pipelining.
+It also gives us the chance to test out how compatible the compiler is with rudimentary batch parallel compilation of a single module.
+So far we can reduce the time to compile Scala 3 itself by a third, compared to no-pipelining.
+We demonstrated that work at Scala Italy, the London Scala User Group and finally the Paris Scala User Group.
+
+### Scala 3 New Features
+
+For Scala 3.
+
+#### SIP-57 `runtimeCheck`
+
+We made a proposal [SIP-57](https://github.com/scala/improvement-proposals/pull/67) to provide a better replacement for the `@unchecked` annotation, for the purpose of pattern match checking.
+This proposal will enable making unsafe pattern matches an error by default, by providing a convenient and readable way to tell the compiler to ignore checks for safety.
+
+#### Dropping `withFilter` by default in for comprehension in 3.4
+
+In PR [lampepfl/dotty#18842](https://github.com/lampepfl/dotty/pull/18842) we activated the feature to prevent calls to `withFilter` being generated by default in for comprehensions.
+
+The improvement for users is more data types can be used in for comprehensions, as long as the pattern in a generator is statically guaranteed to match, or else report an error.
+Developers can opt out of this check, and generate `withFilter` instead, by adding `case` before a pattern.
+
+### Scala Improvement Process
+
+For Scala 3.
+
+The [Scala Improvement Process](https://docs.scala-lang.org/sips/) coordinates the evolution of the language.
+It ensures that the decisions are made by taking into account the needs of all the stakeholders of the language.
+
+Four SIP meetings happended since the last report.
+Of note: the previously mentioned [SIP-56, Specification for Match Types](https://docs.scala-lang.org/sips/match-types-spec.html), was approved for Implementation and later for Shipping.
+Several new SIPs are in progress.
+
+### Better error messages for Scala 3
+
+For Scala 3.
+
+In Q4 we started a campaign to get users to report problematic error/warning messages in Scala 3.
+We created a new [issue template](https://github.com/lampepfl/dotty/pull/18672) and promoted it in [a blog](https://scala-lang.org/blog/2023/10/17/feedback-wanted-error-messages.html).
+At the start we got many issues reported using the new template, and a lot of them were improved by compiler contributors, as we reported [on social media](https://x.com/scala_lang/status/1720423780382634276?s=20).
+
+At the Center itself we worked on improving the reporting of mismatched TASTy versions, as seen in PR [lampepfl/dotty#18828](https://github.com/lampepfl/dotty/pull/18828).
+
+We plan to promote this initiative again.
+
+## Developer Experience
+
+### Stable Presentation Compiler
+
+For Scala 3.
+
+This quarter, we focused on simplification and stabilisation of the Presentation Compiler of Scala 3.
+The work includes missing code completion inside extension constructs, better error recovery from errors and alignment of text replacement logic with respect to Scala 2.
+In terms of stability, we refactored the implementation of completions to rely on compiler logic, which not only deduplicated computations but also added missing completions.
+
+### sbt
+
+For Scala 2 and Scala 3.
+
+We have been reviewing the big PR ([sbt/sbt#6746](https://github.com/sbt/sbt/pull/6746)) opened by Eugene Yokota, which kick-starts the development of sbt 2.
+Following the ["sbt 2 ideas" blog post](https://eed3si9n.com/sbt-2.0-ideas) and [discussion](https://github.com/sbt/sbt/discussions/7174), a significant focus of sbt 2 should be on simplifications and performance improvements.
+After the initial PR was merged, we worked on consolidating and simplifying the internals.
+
+Noteworthy pull requests include:
+
+* [#7444 Reduce abstraction in `Execute` and around](https://github.com/sbt/sbt/pull/7444)
+* [#7456 Remove `AList`, replace it with `TupleMapExtension`](https://github.com/sbt/sbt/pull/7456)
+
+### Debugger in Metals
+
+For Scala 3 mostly.
+
+We made significant progress on Better Stack Traces for the debugger.
+We finished the main work on decoding class files and method names.
+We are now working on releasing an independent library for decoding stack traces, which will provide better stack traces for the debugger itself, but also Scastie, scala-cli, running applications, etc.
+
+We also improved on smaller areas of the debugger: better information for Metals, support of Scala 3.4, and better handling of exported methods.
+
+### Support Scala CLI in Scala Steward
+
+For Scala 2 and 3.
+
+Scala Steward became a critical tool for maintenance of open source projects.
+It had minimal support for Scala CLI projects for a long time, but now in PR [scala-steward-org/scala-steward#3188](https://github.com/scala-steward-org/scala-steward/pull/3188) we added support for the various ways to declare dependencies with using directives.
+
+### Scastie maintenance
+
+For Scala 2 and 3.
+
+We made various improvements to Scastie, mostly affecting the editor experience.
+This includes the new tree-sitter-based syntax highlighter that we mentioned in the last report.
+
+We started collecting Metals crashes happening within Scastie, which will be used to improve the quality and stability of our tooling.
+
+### Scastie Scala-CLI
+
+For Scala 2 and 3.
+
+We resumed work on scala-cli support for Scastie.
+It is now under review, and we are still working on it for the upcoming quarter.
+This improvement will improve the performance of Scastie and will provide a fully-pledged scala-cli in the browser.
+
+### tasty-query maintenance
+
+For Scala 2 and 3.
+
+We fixed a number issues in [tasty-query](https://github.com/scalacenter/tasty-query), notably when processing Scala 2 artifacts.
+They were mostly driven by the needs of the debugger, mentioned above.
+
+We made the entire API of tasty-query thread-safe.
+It is now possible to safely use tasty-query from parallel algorithms.
+As a concrete use case, we have a prototype of [tasty-mima](https://github.com/scalacenter/tasty-mima) running in parallel, making it about twice as fast.
+
+## Documentation and Education
+
+### Work-in-progress AI integration
+
+For Scala 2 and Scala 3.
+
+We are investigating the possibility of improving the usability of the Scala documentation by integrating it with the latest advancements in AI.
+At the moment, we are in an exploratory phase internally within the Scala Center.
+We have a prototype implementation for question-answering with internal data.
+We are planning to extend this solution to the Scala documentation so that Scala users can get their questions answered in chat format.
+
+## Community and Contributor Experience
+
+For Scala 2 and Scala 3 throughout.
+
+#### Scala Advent of Code
+
+As in the past two years, we stewarded the participation to [Advent of Code](https://adventofcode.com/) for Scala developers.
+
+One of our core priorities is to communicate excitement about Scala.
+We participate in the Advent of Code so that we can share to the wider programming community how great Scala is for solving these programming puzzles.
+Another key priority is to improve the onboarding experience for newcomers.
+We hope that we will be able to share the solutions as a "Scala by Example" showcase to newcomers, giving a vital first impression of elegant Scala code.
+
+This year, we increased overall engagement from the community, with 45% more solutions contributed than last year, and many first-time participants in the Scala Discord channel.
+We also engaged many more volunteers from outside of the Scala Center to write articles (with 100% coverage: each day now has a full article!), a vast improvement from 2022.
+We could have done more promotion but overall we had good results.
+
+See the [announcement blog](https://scala-lang.org/blog/2023/11/23/advent-of-code-announce.html) and [recap blog](https://scala-lang.org/blog/2024/01/10/advent-of-code-recap.html) for more details.
+
+### Compiler Sprees
+
+We maintained our involvement in the [Scala 3 Compiler Academy Issue Spree](https://www.scala-lang.org/blog/2022/11/02/compiler-academy.html).
+We collaborated with both new and experienced contributors on issues such as [dotty#19464](https://github.com/lampepfl/dotty/pull/19464) and [dotty#19463](https://github.com/lampepfl/dotty/pull/19463).
+
+Since its inception, the compiler spree has helped close [more then a hundred issues](https://github.com/lampepfl/dotty/issues?q=is%3Aissue+sort%3Aupdated-desc+label%3ASpree+is%3Aclosed) with the help of over 80 contributors.
+
+### GSoC 2023 Finalization
+
+During this quarter, we finalized the cycle for the 2023 edition of Google Summer of Code.
+Six students successfully completed their projects.
+You can read more about our GSoC 2023 results, including all the projects our contributors worked on, in [our dedicated blog article](https://scala-lang.org/blog/2023/12/20/gsoc-report.html).
+
+### Collaboration with ESL
+
+As part of our effort to promote usage of Scala at EPFL, and to gather the Scala community around common initiatives, we started a collaboration with the Embedded Systems Lab at EPFL.
+They have an interest in using Scala for circuits design with Chisel.
+Our common objective is to establish a semester project track for students at EPFL in which they can do hardware design with Scala as part of their studies.
+
+Currently, we are in the process of helping ESL to integrate Chisel within their existing System Verilog-based setup.
+Once done, the work will be available on GitHub and may be also useful for people outside EPFL who are working in the domain.
+
+### Scala Center Fundraising Initiative
+
+We continued our ongoing fundraising effort, exploring various avenues to establish partnerships with the industry.
+We have started to research the possibility of registering the Scala Center as a US non-profit, which would allow contributions from US-based companies to be tax-exempt.
+We are also working on the structure of our corporate membership.
+Both of these are work in progress.