About a year ago, Dune got a new experimental feature called "library variants". This feature is an automated selection mechanism for virtual libraries. Because this feature has a high-cost in terms of code complexity and maintenance and also getting the design right turned out to be difficult, we decided to mark this feature as experimental and guard it under a (using library_variants 0.1) stanza in the dune-project file.

We would now like to move forward and either commit to long term support by promoting this feature to the vanilla language, or discard it entirely and simplify the Dune code base, making room for other exciting features.

From our point of view, it seems that this feature is unused. However, we wanted to get feedback from the community before making a decision.

So please react to this message with:

• 👍 if you are using library variants (please also post a link to the use case if public)
• 👎 if you are not using library variants
• 👀 if you wanted to try library variants but didn't because they were experimental

The default choice will be to drop support for library variants.

Note that this only concerns library variants, not virtual libraries. Virtual libraries are part of the vanilla dune language and there is no plan to get rid of them at this point.