Searching for dependencies in pom editor

[kjsmita6]

While working on #824 , I noticed that MavenPomSelectionComponent.SearchJob#run seems to not do anything, and contains the comment // TODO used to be indexer, replace with Central search. This was as a result of me investigating complaints that people are unable to add dependencies using the pom editor's "Add Dependency" button, even when adding workspace projects.

1. Is this a result of the recent removal of the Maven indexer project?
2. Is there any plan to add this functionality back in the future or is there another way to make this dialog work again?

[mickaelistria]

Is this a result of the recent removal of the Maven indexer project?

Yes.

Is there any plan to add this functionality back in the future or is there another way to make this dialog work again?

If someone contributes it, it would for sure be welcome. However, using Ctrl+Space does provide assistance based on Central Search. Maybe we should just remove the button and let people use content assist directly.

[laeubi]

I think the Ctrl+Space search is rather hard to use (e.g. if there are large results) and its unclear how exactly to filter items while the dialog gives good assistance. For that it would be great to have it working again.

[HannesWell]

I think the Ctrl+Space search is rather hard to use (e.g. if there are large results)

If there are too many results I just type in more which usually leads to more specific results.

Nevertheless I understand if some prefer the dialog.
Wouldn't it be possible to somehow 're-direct' input and output for/from the content assist with the dialog to not have to duplicate the code?

[laeubi]

If there are too many results I just type in more which usually leads to more specific results.

This works great if you know what you are searching for :-) But for example just try "commons" or "urtils" and you get a long list, now assume you are unsure if you should use commons-io or org.apache.commons group Id and now when the editor lost focus all your search is lost...

Beside that (at least for me) this is sometimes really slow and computing for "ages", and I always wonder if/where I should start the completion, also sometimes it suggest then some insertion of tags and so on... also the dialog is usually to small so one has to make it wider but content assist don't save this and so one needs to do this each time.

Wouldn't it be possible to somehow 're-direct' input and output for/from the content assist with the dialog to not have to duplicate the code?

I think that's the idea, but if I remember last discussion @mickaelistria said there is no "standard" way to trigger the LanguageServer code for this...

[kjsmita6]

Is this a result of the recent removal of the Maven indexer project?

Yes.

Is there any plan to add this functionality back in the future or is there another way to make this dialog work again?

If someone contributes it, it would for sure be welcome. However, using Ctrl+Space does provide assistance based on Central Search. Maybe we should just remove the button and let people use content assist directly.

Using control space on the latest checkout of master does not give anything, and actually just gives an error.

Caused by: java.lang.NullPointerException: Cannot invoke "org.eclipse.m2e.core.ui.internal.search.util.SearchEngine.findGroupIds(String, org.eclipse.m2e.core.ui.internal.search.util.Packaging, org.eclipse.m2e.core.ui.internal.search.util.ArtifactInfo)" because the return value of "org.eclipse.m2e.core.ui.internal.util.ProposalUtil.getSearchEngine(org.eclipse.core.resources.IProject)" is null
	at org.eclipse.m2e.core.ui.internal.util.ProposalUtil$4.search(ProposalUtil.java:183)
	at org.eclipse.m2e.core.ui.internal.util.ProposalUtil.lambda$0(ProposalUtil.java:99)
	at org.eclipse.jface.fieldassist.ContentProposalAdapter.getProposals(ContentProposalAdapter.java:2033)
	at org.eclipse.jface.fieldassist.ContentProposalAdapter.openProposalPopup(ContentProposalAdapter.java:1880)
	at org.eclipse.jface.fieldassist.ContentProposalAdapter.openProposalPopup(ContentProposalAdapter.java:1910)
	at org.eclipse.ui.fieldassist.ContentAssistCommandAdapter$1.execute(ContentAssistCommandAdapter.java:82)
	at org.eclipse.ui.internal.handlers.E4HandlerProxy.execute(E4HandlerProxy.java:97)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:58)
	... 76 more

Because the method ProposalUtil.getSearchEngine(IProject) always returns null because there are no classes that implement SearchEngine (the class that implemented it was removed with the indexer project). So I think this content assist should either be removed to prevent errors (and not mislead users) or add back some sort of SearchEngine that "works".