UnsupportedOperationException when using Code Completion

[davidbauer99]

I frequently see the included error when using RubyMine's code completion features (ie: tab complete or enter complete). When this happens, hitting tab will clear the partially entered code symbol and close the completion window. For example:

1. Have a list named my_list.
2. Start typing my_list.sort which brings up a code completion dialog
3. Navigate to sort_by in the dialog
4. Hit tab which will revert the current line to my_list. and close the dialog.

RubyMine Version: 2022.2, Build #RM-222.3345.111, built on July 25, 2022
Plugin Version: 1.6.1

Stacktrace

java.lang.UnsupportedOperationException: empty.tail
	at scala.collection.TraversableLike.tail(TraversableLike.scala:421)
	at scala.collection.TraversableLike.tail$(TraversableLike.scala:420)
	at scala.collection.immutable.StringOps.scala$collection$IndexedSeqOptimized$$super$tail(StringOps.scala:29)
	at scala.collection.IndexedSeqOptimized.tail(IndexedSeqOptimized.scala:128)
	at scala.collection.IndexedSeqOptimized.tail$(IndexedSeqOptimized.scala:128)
	at scala.collection.immutable.StringOps.tail(StringOps.scala:29)
	at com.github.gtache.lsp.editor.EditorEventManager.$anonfun$completion$2(EditorEventManager.scala:318)
	at com.github.gtache.lsp.editor.EditorEventManager.$anonfun$completion$2$adapted(EditorEventManager.scala:314)
	at scala.collection.TraversableLike.$anonfun$map$1(TraversableLike.scala:234)
	at scala.collection.Iterator.foreach(Iterator.scala:929)
	at scala.collection.Iterator.foreach$(Iterator.scala:929)
	at scala.collection.AbstractIterator.foreach(Iterator.scala:1417)
	at scala.collection.IterableLike.foreach(IterableLike.scala:71)
	at scala.collection.IterableLike.foreach$(IterableLike.scala:70)
	at scala.collection.AbstractIterable.foreach(Iterable.scala:54)
	at scala.collection.TraversableLike.map(TraversableLike.scala:234)
	at scala.collection.TraversableLike.map$(TraversableLike.scala:227)
	at scala.collection.AbstractTraversable.map(Traversable.scala:104)
	at com.github.gtache.lsp.editor.EditorEventManager.prepareTemplate$1(EditorEventManager.scala:314)
	at com.github.gtache.lsp.editor.EditorEventManager.$anonfun$completion$16(EditorEventManager.scala:411)
	at com.intellij.codeInsight.lookup.LookupElementBuilder.handleInsert(LookupElementBuilder.java:373)
	at com.intellij.codeInsight.lookup.LookupElementDecorator.handleInsert(LookupElementDecorator.java:75)
	at com.intellij.codeInsight.completion.CodeCompletionHandlerBase.lambda$insertItem$14(CodeCompletionHandlerBase.java:689)
	at com.intellij.util.indexing.FileBasedIndex.lambda$ignoreDumbMode$0(FileBasedIndex.java:202)
	at com.intellij.openapi.util.RecursionManager$1.computePreventingRecursion(RecursionManager.java:114)
	at com.intellij.util.indexing.FileBasedIndexEx.ignoreDumbMode(FileBasedIndexEx.java:663)
	at com.intellij.util.indexing.FileBasedIndex.ignoreDumbMode(FileBasedIndex.java:201)
	at com.intellij.util.indexing.DumbModeAccessType.ignoreDumbMode(DumbModeAccessType.java:43)
	at com.intellij.codeInsight.completion.CodeCompletionHandlerBase.lambda$insertItem$15(CodeCompletionHandlerBase.java:688)
	at com.intellij.openapi.application.impl.ApplicationImpl.runWriteAction(ApplicationImpl.java:1023)
	at com.intellij.codeInsight.completion.CodeCompletionHandlerBase.insertItem(CodeCompletionHandlerBase.java:672)
	at com.intellij.codeInsight.completion.CodeCompletionHandlerBase.lambda$doInsertItem$12(CodeCompletionHandlerBase.java:597)
	at com.intellij.openapi.editor.impl.CaretModelImpl.lambda$runForEachCaret$3(CaretModelImpl.java:312)
	at com.intellij.openapi.editor.impl.CaretModelImpl.doWithCaretMerging(CaretModelImpl.java:421)
	at com.intellij.openapi.editor.impl.CaretModelImpl.runForEachCaret(CaretModelImpl.java:321)
	at com.intellij.openapi.editor.impl.CaretModelImpl.runForEachCaret(CaretModelImpl.java:296)
	at com.intellij.codeInsight.completion.CodeCompletionHandlerBase.doInsertItem(CodeCompletionHandlerBase.java:587)
	at com.intellij.codeInsight.completion.CodeCompletionHandlerBase.insertItemHonorBlockSelection(CodeCompletionHandlerBase.java:547)
	at com.intellij.codeInsight.completion.CodeCompletionHandlerBase.lookupItemSelected(CodeCompletionHandlerBase.java:493)
	at com.intellij.codeInsight.completion.CompletionProgressIndicator.itemSelected(CompletionProgressIndicator.java:180)
	at com.intellij.codeInsight.completion.BaseCompletionLookupArranger.itemSelected(BaseCompletionLookupArranger.java:218)
	at com.intellij.codeInsight.lookup.impl.LookupImpl.fireItemSelected(LookupImpl.java:940)
	at com.intellij.codeInsight.lookup.impl.LookupImpl.finishLookupInWritableFile(LookupImpl.java:583)
	at com.intellij.codeInsight.lookup.impl.LookupImpl.lambda$finishLookup$7(LookupImpl.java:541)
	at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:210)
	at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:174)
	at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:164)
	at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:150)
	at com.intellij.codeInsight.lookup.impl.LookupImpl.finishLookup(LookupImpl.java:541)
	at com.intellij.codeInsight.lookup.impl.LookupImpl.finishLookup(LookupImpl.java:526)
	at com.intellij.codeInsight.lookup.impl.actions.ChooseItemAction$Handler.lambda$doExecute$0(ChooseItemAction.java:72)
	at com.intellij.util.SlowOperations.allowSlowOperations(SlowOperations.java:149)
	at com.intellij.codeInsight.lookup.impl.actions.ChooseItemAction$Handler.doExecute(ChooseItemAction.java:72)
	at com.intellij.openapi.editor.actionSystem.DynamicEditorActionHandler.doExecute(DynamicEditorActionHandler.java:63)
	at com.intellij.openapi.editor.actionSystem.EditorActionHandler.lambda$execute$4(EditorActionHandler.java:199)
	at com.intellij.openapi.editor.actionSystem.EditorActionHandler.doIfEnabled(EditorActionHandler.java:89)
	at com.intellij.openapi.editor.actionSystem.EditorActionHandler.execute(EditorActionHandler.java:198)
	at com.intellij.openapi.editor.actionSystem.EditorAction.lambda$actionPerformed$0(EditorAction.java:93)
	at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:219)
	at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:174)
	at com.intellij.openapi.editor.actionSystem.EditorAction.actionPerformed(EditorAction.java:102)
	at com.intellij.openapi.editor.actionSystem.EditorAction.actionPerformed(EditorAction.java:77)
	at com.intellij.openapi.actionSystem.ex.ActionUtil.doPerformActionOrShowPopup(ActionUtil.java:315)
	at com.intellij.openapi.keymap.impl.ActionProcessor.performAction(ActionProcessor.java:47)
	at com.intellij.openapi.keymap.impl.IdeKeyEventDispatcher$1.performAction(IdeKeyEventDispatcher.java:581)
	at com.intellij.openapi.keymap.impl.IdeKeyEventDispatcher.lambda$doPerformActionInner$9(IdeKeyEventDispatcher.java:703)
	at com.intellij.openapi.application.TransactionGuardImpl.performActivity(TransactionGuardImpl.java:105)
	at com.intellij.openapi.application.TransactionGuardImpl.performUserActivity(TransactionGuardImpl.java:94)
	at com.intellij.openapi.keymap.impl.IdeKeyEventDispatcher.lambda$doPerformActionInner$10(IdeKeyEventDispatcher.java:703)
	at com.intellij.openapi.actionSystem.ex.ActionUtil.performDumbAwareWithCallbacks(ActionUtil.java:337)
	at com.intellij.openapi.keymap.impl.IdeKeyEventDispatcher.doPerformActionInner(IdeKeyEventDispatcher.java:700)
	at com.intellij.openapi.keymap.impl.IdeKeyEventDispatcher.processAction(IdeKeyEventDispatcher.java:644)
	at com.intellij.openapi.keymap.impl.IdeKeyEventDispatcher.processAction(IdeKeyEventDispatcher.java:592)
	at com.intellij.openapi.keymap.impl.IdeKeyEventDispatcher.processActionOrWaitSecondStroke(IdeKeyEventDispatcher.java:475)
	at com.intellij.openapi.keymap.impl.IdeKeyEventDispatcher.inInitState(IdeKeyEventDispatcher.java:464)
	at com.intellij.openapi.keymap.impl.IdeKeyEventDispatcher.dispatchKeyEvent(IdeKeyEventDispatcher.java:229)
	at com.intellij.ide.IdeEventQueue.dispatchKeyEvent(IdeEventQueue.java:804)
	at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:740)
	at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$6(IdeEventQueue.java:439)
	at com.intellij.openapi.progress.impl.CoreProgressManager.computePrioritized(CoreProgressManager.java:791)
	at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$7(IdeEventQueue.java:438)
	at com.intellij.openapi.application.TransactionGuardImpl.performActivity(TransactionGuardImpl.java:113)
	at com.intellij.ide.IdeEventQueue.performActivity(IdeEventQueue.java:604)
	at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$8(IdeEventQueue.java:436)
	at com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:881)
	at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:484)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:207)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
	at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:92)