LinkageError: loader constraint violation

I'm getting the following error when targeting PyCharm Professional 2024.2, with a dependency on both the native client and LSP4IJ:

java.lang.LinkageError: loader constraint violation: loader com.intellij.ide.plugins.cl.PluginClassLoader @182fa87a wants to load class org.eclipse.lsp4j.Diagnostic. A different class with the same name was previously loaded by com.intellij.util.lang.PathClassLoader @65ab7765. (org.eclipse.lsp4j.Diagnostic is in unnamed module of loader com.intellij.util.lang.PathClassLoader @65ab7765)
	at insyncwithfoo.plugin.lsp.DiagnosticsSupportKt.getCodeAsString(DiagnosticsSupport.kt:10)
	at insyncwithfoo.plugin.lsp.DiagnosticsSupportKt.access$getCodeAsString(DiagnosticsSupport.kt:1)
	at insyncwithfoo.plugin.lsp.DiagnosticsSupport.getTooltip(DiagnosticsSupport.kt:19)
	at com.intellij.platform.lsp.api.customization.LspDiagnosticsSupport.createAnnotation(LspDiagnosticsSupport.kt:28)
	at com.intellij.platform.lsp.impl.highlighting.LspAnnotator.q(LspAnnotator.kt:71)
	at com.intellij.platform.lsp.impl.highlighting.LspAnnotator.annotate(LspAnnotator.kt:51)
	at com.intellij.codeInsight.daemon.impl.AnnotationHolderImpl.runAnnotatorWithContext(AnnotationHolderImpl.java:216)
	at com.intellij.codeInsight.daemon.impl.AnnotatorRunner.lambda$runAnnotator$3(AnnotatorRunner.java:139)
	at com.intellij.codeInsight.daemon.impl.AnnotationSessionImpl.computeWithSession(AnnotationSessionImpl.java:87)
	at com.intellij.codeInsight.daemon.impl.AnnotatorRunner.runAnnotator(AnnotatorRunner.java:129)
	at com.intellij.codeInsight.daemon.impl.AnnotatorRunner.lambda$runAnnotatorsAsync$0(AnnotatorRunner.java:66)
	at com.intellij.openapi.application.impl.AnyThreadWriteThreadingSupport.tryRunReadAction(AnyThreadWriteThreadingSupport.kt:279)
	at com.intellij.openapi.application.impl.ApplicationImpl.tryRunReadAction(ApplicationImpl.java:965)
	at com.intellij.codeInsight.daemon.impl.AnnotatorRunner.lambda$runAnnotatorsAsync$1(AnnotatorRunner.java:66)
	at com.intellij.concurrency.JobLauncherImpl$2MyProcessQueueTask.lambda$call$0(JobLauncherImpl.java:494)
	at com.intellij.openapi.progress.impl.CoreProgressManager.lambda$executeProcessUnderProgress$13(CoreProgressManager.java:660)
	at com.intellij.openapi.progress.impl.CoreProgressManager.computeUnderProgress(CoreProgressManager.java:684)
	at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:659)
	at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:79)
	at com.intellij.concurrency.JobLauncherImpl$2MyProcessQueueTask.call(JobLauncherImpl.java:483)
	at com.intellij.concurrency.JobLauncherImpl$2MyProcessQueueTask.call(JobLauncherImpl.java:471)
	at com.intellij.concurrency.JobLauncherImpl$2.compute(JobLauncherImpl.java:456)
	at java.base/java.util.concurrent.CountedCompleter.exec(CountedCompleter.java:759)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:507)
	at java.base/java.util.concurrent.ForkJoinTask.invoke(ForkJoinTask.java:676)
	at com.intellij.concurrency.JobLauncherImpl.procInOrderAsync(JobLauncherImpl.java:554)
	at com.intellij.codeInsight.daemon.impl.AnnotatorRunner.runAnnotatorsAsync(AnnotatorRunner.java:67)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.collectHighlights(GeneralHighlightingPass.java:231)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.lambda$collectInformationWithProgress$10(GeneralHighlightingPass.java:176)
	at com.intellij.codeInsight.daemon.impl.HighlightVisitorRunner.createHighlightVisitorsFor(HighlightVisitorRunner.java:84)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.collectInformationWithProgress(GeneralHighlightingPass.java:109)
	at com.intellij.codeInsight.daemon.impl.ProgressableTextEditorHighlightingPass.doCollectInformation(ProgressableTextEditorHighlightingPass.java:84)
	at com.intellij.codeHighlighting.TextEditorHighlightingPass.collectInformation(TextEditorHighlightingPass.java:57)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.lambda$doRun$2(PassExecutorService.java:418)
	at com.intellij.platform.diagnostic.telemetry.helpers.TraceKt.runWithSpanIgnoreThrows(trace.kt:118)
	at com.intellij.platform.diagnostic.telemetry.helpers.TraceUtil.runWithSpanThrows(TraceUtil.java:36)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.lambda$doRun$3(PassExecutorService.java:413)
	at com.intellij.openapi.application.impl.AnyThreadWriteThreadingSupport.tryRunReadAction(AnyThreadWriteThreadingSupport.kt:291)
	at com.intellij.openapi.application.impl.ApplicationImpl.tryRunReadAction(ApplicationImpl.java:965)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.lambda$doRun$4(PassExecutorService.java:404)
	at com.intellij.openapi.progress.impl.CoreProgressManager.lambda$executeProcessUnderProgress$13(CoreProgressManager.java:660)
	at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:735)
	at com.intellij.openapi.progress.impl.CoreProgressManager.computeUnderProgress(CoreProgressManager.java:691)
	at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:659)
	at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:79)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.doRun(PassExecutorService.java:403)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.lambda$run$0(PassExecutorService.java:379)
	at com.intellij.openapi.fileTypes.impl.FileTypeManagerImpl.cacheFileTypesInside(FileTypeManagerImpl.java:802)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.lambda$run$1(PassExecutorService.java:379)
	at com.intellij.openapi.application.impl.AnyThreadWriteThreadingSupport.executeByImpatientReader(AnyThreadWriteThreadingSupport.kt:486)
	at com.intellij.openapi.application.impl.ApplicationImpl.executeByImpatientReader(ApplicationImpl.java:179)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.run(PassExecutorService.java:377)
	at com.intellij.concurrency.JobLauncherImpl$VoidForkJoinTask$1.exec(JobLauncherImpl.java:190)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:507)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1491)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:2073)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:2035)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:187)

It might have something to do with this one in the docs, but I'm not sure.

If codebase access is necessary, give me a ping.

Start with the dependency setup for the native client and LSP4IJ targeting PyCharm Professional 2024.2, then inspect DiagnosticsSupport.kt at line 10 and the DeveloperGuide section “exclude all lsp4j dependencies.” Reproduce the loader constraint violation and verify completion by confirming diagnostics tooltips work without the duplicate-class error.