NullPointerException: Cannot read field "width" because "this.componentInnards" is null

Created by: benfry

Seen in 4.0, but not clear if this is downstream problems caused by https://github.com/processing/processing4/issues/530 or if it's an error triggered by changing between themes.

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException: Cannot read field "width" because "this.componentInnards" is null
at java.desktop/javax.swing.plaf.basic.BasicProgressBarUI.updateSizes(BasicProgressBarUI.java:542)
at java.desktop/javax.swing.plaf.basic.BasicProgressBarUI.getBox(BasicProgressBarUI.java:499)
at java.desktop/javax.swing.plaf.basic.BasicProgressBarUI.paintIndeterminate(BasicProgressBarUI.java:656)
at java.desktop/javax.swing.plaf.basic.BasicProgressBarUI.paint(BasicProgressBarUI.java:464)
at java.desktop/javax.swing.plaf.ComponentUI.update(ComponentUI.java:161)
at java.desktop/javax.swing.JComponent.paintComponent(JComponent.java:842)
at java.desktop/javax.swing.JComponent.paint(JComponent.java:1119)
at java.desktop/javax.swing.JComponent.paintToOffscreen(JComponent.java:5311)
at java.desktop/javax.swing.RepaintManager$PaintManager.paintDoubleBufferedImpl(RepaintManager.java:1657)
at java.desktop/javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1632)
at java.desktop/javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1570)
at java.desktop/javax.swing.RepaintManager.paint(RepaintManager.java:1337)
at java.desktop/javax.swing.JComponent._paintImmediately(JComponent.java:5259)
at java.desktop/javax.swing.JComponent.paintImmediately(JComponent.java:5069)
at java.desktop/javax.swing.RepaintManager$4.run(RepaintManager.java:879)
at java.desktop/javax.swing.RepaintManager$4.run(RepaintManager.java:862)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.desktop/javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:862)
at java.desktop/javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:835)
at java.desktop/javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:784)
at java.desktop/javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1898)
at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:318)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:771)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:722)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:716)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:741)
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)

Bắt đầu bằng cách tái hiện lỗi trong Processing 4 khi thay đổi theme, sau đó lần theo đường dẫn vẽ thanh tiến trình được hiển thị trong stack trace của BasicProgressBarUI. So sánh hành vi này với vấn đề downstream có thể có trong processing4#530; hoàn thành có nghĩa là việc thay đổi theme không còn tạo ra NullPointerException này.