NPE when editing certain python files and code folding is enabled

[Piotr Skowronek]

Description
NPE when editing certain python files and code folding is enabled

Steps to Reproduce
Specific steps to reproduce the behavior:

1. Replace sample file RSyntaxTextAreaDemo/src/main/resources/org/fife/ui/rsyntaxtextarea/demo/PythonExample.txt with the one that contains this python file:
   wontopen.zip

2. Run demo app ./gradlew run

3. Enable Code folding

4. Switch to Python example

Expected behavior
No NPE is being thrown

Actual behavior
NPE is thrown

Stacktrace

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
        at org.fife.ui.rsyntaxtextarea.folding.PythonFoldParser.getFolds(PythonFoldParser.java:87)
        at org.fife.ui.rsyntaxtextarea.folding.DefaultFoldManager.reparse(DefaultFoldManager.java:445)
        at org.fife.ui.rsyntaxtextarea.folding.DefaultFoldManager$Listener.propertyChange(DefaultFoldManager.java:546)
        at java.desktop/java.beans.PropertyChangeSupport.fire(PropertyChangeSupport.java:341)
        at java.desktop/java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:334)
        at java.desktop/java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:266)
        at java.desktop/java.awt.Component.firePropertyChange(Component.java:8732)
        at org.fife.ui.rsyntaxtextarea.RSyntaxTextArea.setSyntaxEditingStyle(RSyntaxTextArea.java:3044)
        at org.fife.ui.rsyntaxtextarea.demo.DemoRootPane$ChangeSyntaxStyleAction.actionPerformed(DemoRootPane.java:370)
        at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1967)
        at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2308)
        at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)
        at java.desktop/javax.swing.JToggleButton$ToggleButtonModel.setPressed(JToggleButton.java:401)
        at java.desktop/javax.swing.AbstractButton.doClick(AbstractButton.java:369)
        at java.desktop/javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1020)
        at java.desktop/com.apple.laf.AquaMenuItemUI.doClick(AquaMenuItemUI.java:157)
        at java.desktop/javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1064)
        at java.desktop/java.awt.Component.processMouseEvent(Component.java:6636)
        at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)
        at java.desktop/java.awt.Component.processEvent(Component.java:6401)
        at java.desktop/java.awt.Container.processEvent(Container.java:2263)
        at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5012)
        at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)
        at java.desktop/java.awt.Component.dispatchEvent(Component.java:4844)
        at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4919)
        at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4548)
        at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4489)
        at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307)
        at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2764)
        at java.desktop/java.awt.Component.dispatchEvent(Component.java:4844)
        at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
        at java.base/java.security.ProtectionDomain$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:745)
        at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
        at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
        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)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
        at org.fife.ui.rsyntaxtextarea.folding.PythonFoldParser.getFolds(PythonFoldParser.java:87)
        at org.fife.ui.rsyntaxtextarea.folding.DefaultFoldManager.reparse(DefaultFoldManager.java:445)
        at org.fife.ui.rsyntaxtextarea.folding.DefaultFoldManager$1.parse(DefaultFoldManager.java:477)
        at org.fife.ui.rsyntaxtextarea.ParserManager.actionPerformed(ParserManager.java:163)
        at java.desktop/javax.swing.Timer.fireActionPerformed(Timer.java:317)
        at java.desktop/javax.swing.Timer$DoPostEvent.run(Timer.java:249)
        at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:316)
        at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:770)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
        at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:740)
        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)

Java version
Java(TM) SE Runtime Environment (build 14.0.2+12-46), macOS 10.15.7

Additional context
It breaks muC Editor/Viewer as described here: mucommander/mucommander#983

[bobbylight]

Fixed by #508 (4a08790)