Unhandled null in getWorkDoneProgress() breaks Vim usage

[Tachi107]

Hi all, pull request #2776 (commit 2774467) broke jdtls for me when using it in Vim with the vim9 lsp plugin. More specifically, the getWorkDoneProgress() method is returning null, which causes a null pointer exception when using it in the new isWorkDoneProgressSupported() method.

Here's the error message shown by the lsp plugin when using jdtls 1.27.0:

'jdtls' Language Server Messages
================================
10/30/23 11:34:42: [Error]: 30 ott 2023, 11:34:42 Unhandled error
Cannot invoke "java.lang.Boolean.booleanValue()" because the return value of "org.eclipse.lsp4j.WindowClientCapabilities.getWorkDoneProgress()" is null
java.lang.NullPointerException: Cannot invoke "java.lang.Boolean.booleanValue()" because the return value of "org.eclipse.lsp4j.WindowClientCapabilities.getWorkDoneProgress()" is null
	at org.eclipse.jdt.ls.core.internal.preferences.ClientPreferences.isWorkDoneProgressSupported(ClientPreferences.java:185)
	at org.eclipse.jdt.ls.core.internal.handlers.ProgressReporterManager$ProgressReporter.sendStatus(ProgressReporterManager.java:262)
	at org.eclipse.jdt.ls.core.internal.handlers.ProgressReporterManager$ProgressReporter.sendProgress(ProgressReporterManager.java:239)
	at org.eclipse.jdt.ls.core.internal.handlers.ProgressReporterManager$ProgressReporter.done(ProgressReporterManager.java:222)
	at org.eclipse.jdt.ls.core.internal.handlers.ProgressReporterManager$MulticastProgressReporter.done(ProgressReporterManager.java:102)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:74)

The issue is still present in the 1.29.0 release (and I suspect in the master branch too).

What's the root of the issue here? Is the vim9 lsp plugin doing something wrong, or should jdtls account for nulls returned by getWorkDoneProgress()?

Cc: @hopehadfield

[rgrunber]

Yes, JDT-LS can certainly fix the issue.

The LSP spec defines https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#clientCapabilities :

window?: {
		/**
		 * It indicates whether the client supports server initiated
		 * progress using the `window/workDoneProgress/create` request.
		 *
		 * The capability also controls Whether client supports handling
		 * of progress notifications. If set servers are allowed to report a
		 * `workDoneProgress` property in the request specific server
		 * capabilities.
		 *
		 * @since 3.15.0
		 */
		workDoneProgress?: boolean;

So the value can be true, false, or null (optional).

JDT-LS should definitely handle the null the same way we would handle false.

The client could also work around the issue by setting workdoneProgress to false at https://github.com/yegappan/lsp/blob/38970403dc4d602056ea4028664206ffce74e82a/autoload/lsp/capabilities.vim . If the client supports this capability, they'll need to set it to true (not supported currently in the client).

@hopehadfield feel free to fix on our end.

[Tachi107]

Il giorno lun 30 ott 2023 alle 10:02:28 -07:00:00, Roland Grunberg ***@***.***> ha scritto:

So the value can be true, false, or null (optional). JDT-LS should definitely handle the null the same way we would handle false.

Nice to hear, thanks for your fast response!

The client could also work around the issue by setting workdoneProgress to true at https://github.com/yegappan/lsp/blob/38970403dc4d602056ea4028664206ffce74e82a/autoload/lsp/capabilities.vim but . If the client supports this capability, they'll need to set it to true.

I assume you wanted to write "The client could also work around the issue by setting workdoneProgress to false" (instead of "true"), right? If you think that this vim9 lsp client does indeed support workDoneProgress capability, I'll ask upstream to add it to the capability list. Thanks again :)

[rgrunber]

@Tachi107 , Yes exactly. I think if you're receiving the comment updates by e-mail, you don't see the subsequent edits I do. I updated once i discovered the lsp client mentioned ignores $/progress.