Revamp Jelly completion suggestions

[janfaracik]

This PR sets out to revamp the completion suggestions for .jelly files. It aims to fix several existing issues, as well as add new features.

Existing issues

• Don't prepend namespace if it already exists in Jelly (Don't prepend namespace if it already exists in jelly #190)
• You can get duplicates results (one from IntelliJ, one from this plugin)
• Inconsistent behaviour between the duplicates (IntelliJs will add required fields by default, our implementation does not)

What's new

• Offer suggestions for namespaces that aren't imported yet, based on other files in your project.
• Automatically imports namespaces if they are not already present.
  • I'm often creating new .jelly files from scratch and having to manually add namespaces was a pain, now once you select a completion suggestion the namespace will get automatically imported.
• Generates templates for components with required attributes, offering them to the user as completion suggestions.

Screen.Recording.2024-12-03.at.08.35.57.mov

Testing done

• Tested with core and plugins (Design Library plugin)
• Added some basic tests

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue

[timja]

Need to check the performance of this and how often its called and if there's any caching

[janfaracik]

Aye, need to see if there's any performance regressions, and if so how we can avoid them with cache.

[timja]

this seems to be called on every key press although I didn't notice any delay... might be worth optimising if it doesn't cause other issues

[timja]

I've tested this out and it worked really nicely

[timja]

I'm able to trigger this in Jenkins core with this error message:

Error parsing XSD: Schema not found: hudson.util.jelly.MorphTagLibrary.xsd

Testing with f:textarea

[timja]

I wonder if the value should be a set in some way.

In core everything gets repeated because some files for whatever reason use a different prefix for the namespace.

Alternatively could be just fixed by a PR to core to be consistent...

[duemir]

This is too much, IMO. The built-in XSD-based completion just works. JetBrains maintains it. And as you said, it works better than what we've got. It already knows about required attributes (and more) and adds them automatically. If there duplicates some time, I'd say figure out why and stop showing the duplicates. Don't reinvent the wheel.

[duemir]

You can get duplicates results (one from IntelliJ, one from this plugin)

They are all from this plugin.
IntelliJ only knows about Jelly tag library namespaces because this plugin registers XSDs. src/main/resources/META-INF/plugin.xml#L76-L115
For custom tag libraries that are just resources in a package marked with taglib file, there is src/main/java/org/kohsuke/stapler/idea/descriptor and this java/org/kohsuke/stapler/idea/JellyCompletionContributor.java.

If descriptors and JellyCompletionContributor clash and cause duplicate suggestions. I think it is better to reduce the amount of code and just remove JellyCompletionContributor.