Code Contribution - cannot import into IntelliJ

[VJvaLbhYbfr]

Hello everyone,

I wanted to contribute to Elastic project. I did read CONTRIBUTING.md and followed it both on Ubuntu 20.04 (in VirtualBox) and on Windows 10.

Ubuntu 20.04:
Importing project into IntelliJ (version 2021.1.1 Community Edition) doesn't end with an error, but there are compliation errors almost in every single build.gradle files on import xyz.xyz lines (example - Cannot resolve symbol 'ForbiddenApisPlugin').

Affected imports are from almost every package but org.gradle.*, java.*.

Trying to run app from terminal with ./gradlew :run works perfectly fine. Problem is only in IntelliJ.

What I did to try to solve it:

• I did remove JDK from Project Settings and readded it (it's named 15, and it's OpenJDK's release of Java 15)
• invalidate caches in IntelliJ
• manually clear ~/.gradle/cache folder
• Reload Gradle Project in IntelliJ
• Reload All Gradle Projects in IntelliJ
• Refresh Gradle Dependencies in IntelliJ
• ./gradlew clean :run
• I tried both Gradle runtimes - Specified location (which is version 7.0.2) and 'gradle-wrapper.properties' file in IntelliJ
• for Gradle JVM I tried both version 15 and 16 (yes, it should be 15 only, but I did it, because maybe... )
• git clean -xfd and importing project many times, not only with File/Open... pointing to build.gradle, but in a few other ways as well

Windows 10:
Out of curiosity I tried importing it into IntelliJ on Windows. Importing fails with message:

Build file 'D:\elasticsearch\build.gradle' line: 31

Plugin [id: 'elasticsearch.docker-support'] was not found in any of the following sources:

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

I tried to gradlew.bat :run it in CLI, but it ended with the same error:

D:\elasticsearch
elasticsearch>gradle clean :run

FAILURE: Build failed with an exception.

* Where:
Build file 'D:\elasticsearch\build.gradle' line: 31

* What went wrong:
Plugin [id: 'elasticsearch.docker-support'] was not found in any of the following sources:

- Gradle Core Plugins (plugin is not in 'org.gradle' namespace)
- Plugin Repositories (plugin dependency must include a version number for this source)

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 9s

I mainly work on Ubuntu, so I invested more time into fixing it than the Windows version. But, to be honest, I kinda ran out of ideas.

Does anyone have an idea how to fix it? Or maybe ran into similar problem?