OpenSearch: [BUG] Unable to install lang-painless module when testDistribution is set to INTEG_TEST for k-NN

What is the bug? For k-NN, I am trying to run integ tests on Mac. To do this, I first switched testDistribution from ARCHIVE to INTEG_TEST. Otherwise, it cannot find the OpenSearch artifact:

Execution failed for task ':run'.
> Could not resolve all files for configuration ':opensearch_distro_extracted_testclusters--integTest-0-1.3.0-SNAPSHOT-'.
   > Could not resolve opensearch-distribution-snapshot:opensearch:1.3.0-SNAPSHOT.
     Required by:
         project :
      > Could not resolve opensearch-distribution-snapshot:opensearch:1.3.0-SNAPSHOT.
         > Could not get resource 'https://artifacts.opensearch.org/snapshots/core/opensearch/1.3.0-SNAPSHOT/opensearch-min-1.3.0-SNAPSHOT-darwin-x64-latest.tar.gz'.
            > Could not HEAD 'https://artifacts.opensearch.org/snapshots/core/opensearch/1.3.0-SNAPSHOT/opensearch-min-1.3.0-SNAPSHOT-darwin-x64-latest.tar.gz'. Received status code 403 from server: Forbidden

After making the above switch, it is able to download, but fails with the following error (k-NN has a dependency on lang-painless):

| Exception in thread "main" java.lang.IllegalArgumentException: Missing plugin [lang-painless], dependency of [opensearch-knn]
|       at org.opensearch.plugins.PluginsService.addSortedBundle(PluginsService.java:512)
|       at org.opensearch.plugins.PluginsService.sortBundles(PluginsService.java:480)
|       at org.opensearch.plugins.InstallPluginCommand.jarHellCheck(InstallPluginCommand.java:839)
|       at org.opensearch.plugins.InstallPluginCommand.loadPluginInfo(InstallPluginCommand.java:813)
|       at org.opensearch.plugins.InstallPluginCommand.installPlugin(InstallPluginCommand.java:858)
|       at org.opensearch.plugins.InstallPluginCommand.execute(InstallPluginCommand.java:263)
|       at org.opensearch.plugins.InstallPluginCommand.execute(InstallPluginCommand.java:237)
|       at org.opensearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:100)
|       at org.opensearch.cli.Command.mainWithoutErrorHandling(Command.java:138)
|       at org.opensearch.cli.MultiCommand.execute(MultiCommand.java:104)
|       at org.opensearch.cli.Command.mainWithoutErrorHandling(Command.java:138)
|       at org.opensearch.cli.Command.main(Command.java:101)
|       at org.opensearch.plugins.PluginCli.main(PluginCli.java:60)

This is because the modules do not come with the INTEG_TEST distribution.

So, I create the lang painless module from source and placed it in test resources. Then, I add it as a plugin. However, this then fails with this error:

| ERROR: plugin 'lang-painless' cannot be installed as a plugin, it is a system module

So, I switch this line from plugin to module. However, this then produces the missing plugin error again:

| Exception in thread "main" java.lang.IllegalArgumentException: Missing plugin [lang-painless], dependency of [opensearch-knn]
|       at org.opensearch.plugins.PluginsService.addSortedBundle(PluginsService.java:512)
|       at org.opensearch.plugins.PluginsService.sortBundles(PluginsService.java:480)
|       at org.opensearch.plugins.InstallPluginCommand.jarHellCheck(InstallPluginCommand.java:839)
|       at org.opensearch.plugins.InstallPluginCommand.loadPluginInfo(InstallPluginCommand.java:813)
|       at org.opensearch.plugins.InstallPluginCommand.installPlugin(InstallPluginCommand.java:858)
|       at org.opensearch.plugins.InstallPluginCommand.execute(InstallPluginCommand.java:263)
|       at org.opensearch.plugins.InstallPluginCommand.execute(InstallPluginCommand.java:237)
|       at org.opensearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:100)
|       at org.opensearch.cli.Command.mainWithoutErrorHandling(Command.java:138)
|       at org.opensearch.cli.MultiCommand.execute(MultiCommand.java:104)
|       at org.opensearch.cli.Command.mainWithoutErrorHandling(Command.java:138)
|       at org.opensearch.cli.Command.main(Command.java:101)
|       at org.opensearch.plugins.PluginCli.main(PluginCli.java:60)

I was wondering if there is any way to prevent gradle from attempting to install an extended plugin as a plugin when it is a module.

How can one reproduce the bug? Steps to reproduce the behavior:

1. Clone the repo

git clone https://github.com/jmazanec15/k-NN-1.git
cd k-NN-1 
git checkout build-on-mac

1. Install dependencies

brew install openblas

1. Run build

./gradlew build

What is the expected behavior? Expect to be able to add lang-painless as a module.

What is your host/environment?

• OS: Mac Big Sur
• Version 1.3
• Plugins k-NN, lang-painless