This alert randomly popped up while using IntelliJ - the plugin version I have is 0.0.4. It's possible it was generated shortly after I right-clicked on a project file and chose "Make Executable":
java.lang.Throwable: Assertion failed
at com.intellij.openapi.diagnostic.Logger.assertTrue(Logger.java:197)
at com.intellij.openapi.diagnostic.Logger.assertTrue(Logger.java:206)
at org.jetbrains.ide.BuiltInServerManagerImpl.waitForStart(BuiltInServerManagerImpl.kt:107)
at org.jetbrains.git4idea.ssh.GitXmlRpcHandlerService.getXmlRcpPort(GitXmlRpcHandlerService.java:68)
at git4idea.commands.GitHandlerAuthenticationManager.prepareHttpAuth(GitHandlerAuthenticationManager.java:93)
at git4idea.commands.GitHandlerAuthenticationManager.lambda$prepare$0(GitHandlerAuthenticationManager.java:60)
at git4idea.GitUtil.tryRunOrClose(GitUtil.java:1040)
at git4idea.commands.GitHandlerAuthenticationManager.prepare(GitHandlerAuthenticationManager.java:59)
at git4idea.commands.GitImplBase.run(GitImplBase.java:169)
at git4idea.commands.GitImplBase.runCommand(GitImplBase.java:71)
at com.github.monosoul.git.updateindex.extended.support.CommandInvoker.invoke(CommandInvoker.kt:26)
at com.github.monosoul.git.updateindex.extended.ExtendedUpdateIndexAction.invokeCommand(ExtendedUpdateIndexAction.kt:28)
at com.github.monosoul.git.updateindex.extended.ExtendedUpdateIndexAction.actionPerformed(ExtendedUpdateIndexAction.kt:24)
at com.intellij.openapi.actionSystem.ex.ActionUtil.lambda$performActionDumbAware$5(ActionUtil.java:273)
at com.intellij.util.SlowOperations.lambda$allowSlowOperations$0(SlowOperations.java:77)
at com.intellij.util.SlowOperations.allowSlowOperations(SlowOperations.java:64)
at com.intellij.util.SlowOperations.allowSlowOperations(SlowOperations.java:76)
at com.intellij.openapi.actionSystem.ex.ActionUtil.performActionDumbAware(ActionUtil.java:273)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem$ActionTransmitter.lambda$actionPerformed$0(ActionMenuItem.java:310)
at com.intellij.openapi.wm.impl.FocusManagerImpl.runOnOwnContext(FocusManagerImpl.java:286)
at com.intellij.openapi.wm.impl.IdeFocusManagerImpl.runOnOwnContext(IdeFocusManagerImpl.java:77)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem$ActionTransmitter.actionPerformed(ActionMenuItem.java:299)
at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1967)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem.lambda$fireActionPerformed$0(ActionMenuItem.java:110)
at com.intellij.openapi.application.TransactionGuardImpl.performUserActivity(TransactionGuardImpl.java:95)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem.fireActionPerformed(ActionMenuItem.java:110)
at com.intellij.ui.plaf.beg.BegMenuItemUI.doClick(BegMenuItemUI.java:515)
at com.intellij.ui.plaf.beg.BegMenuItemUI$MyMouseInputHandler.mouseReleased(BegMenuItemUI.java:545)
at java.desktop/java.awt.Component.processMouseEvent(Component.java:6652)
at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3345)
at java.desktop/java.awt.Component.processEvent(Component.java:6417)
at java.desktop/java.awt.Container.processEvent(Container.java:2263)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5027)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4859)
at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4918)
at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4547)
at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4488)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307)
at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2784)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4859)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:778)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:727)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:751)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:749)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:748)
at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:969)
at com.intellij.ide.IdeEventQueue.dispatchMouseEvent(IdeEventQueue.java:906)
at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:836)
at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$8(IdeEventQueue.java:449)
at com.intellij.openapi.progress.impl.CoreProgressManager.computePrioritized(CoreProgressManager.java:808)
at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$9(IdeEventQueue.java:448)
at com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:781)
at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:502)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)