The documentation for migration from 1.x to 2.x of the platform plugin has this section:
It says the migration plugin “…fill[s] all gaps and help users figure out required changes”. However, it doesn’t appear to do anything. What exactly does it do and how do I trigger it to help me figure out the required changes? The documentation is silent on what exactly I should be expecting this plugin to do.
From my own experience, it simply shows some warnings. So, as mentioned in the documentation, you should apply the intellij-platform-plugin v2 along with the migration plugin. The build (gradlew buildPlugin) will probably fail, but the migration plugin may show some useful warning messages like intellij {} should be replaced by the new intellijPlatform {}. AFAIK, there is no OpenRewrite rules or things like that.
The official plugin template v2 can help you, but this is mainly a starter project. You should consider looking at existing open-source plugins that completed their migration.
I didn’t end up needing that plugin. I just brought the build file over from the template project (and libs.versions.toml and gradle.properties) and made a couple of modifications and was able to build and run the plugin with 2.x of the intellij platform plugin.
I am not the original author of the plugin, it seems to have been abandoned and I am seeing if I can add a couple of features to it (it is a custom language plugin for OpenSCAD). Custom language plugins seem to have a huge learning curve…sigh.