Maven Central, pip and conda versions aren't published together

[gabrielfeo]

Currently, a new Kotlin Jupyter kernel version is published to each repository at different times:

• Maven Central: version history
• pypi.org: version history
• Anaconda.org: version history

This is a maintenance problem for authors of libraries that integrate with Jupyter. 0.14.1.547 was the first release to pypi.org and Anaconda.org in almost 9 months while Maven Central received several new versions per week. Since libraries will often depend on the Maven Central artifact, this results in a large distance between what library authors compile/test with and what users of these officially supported installation methods use.

Example case

gabrielfeo/develocity-api-kotlin#426. This library which integrates with the Kotlin kernel was tested using the kernel version published to Maven Central. As that version was frequently updated, the library was able to upgrade its Kotlin Gradle plugin version, which implicitly updates the library's target language version, and pass integration tests. However, until recently pip users would encounter a runtime error using the library with the latest kernel published to the pypi.org stable channel, 0.12.322, which didn't support that language version.

Proposed solution

Please consider only publishing new versions to the 3 repositories in sync.

[ileasile]

Hi! The problem is that we have 3Gb limit on Anaconda and 10Gb limit on PyPi. We do publish every release in our dev channels (see installation instructions) but we clean these places often in order to free up some space.

But we can set up a trigger for publishing to the stable channels, say, 4 times a year.