NPE in clipboard copy

I get an NPE when pressing Ctrl+C, but only if the selection includes a line separator and ends at the beginning of a line.

This is a regression. Used 0.7-M3 before where it worked. So I checked out various commits to find out the commit that broke it. It is commit a2aa8813e48e91e9eef461c20d28c5eac8724592. It works when I checkout the previous commit.

To reproduce, run this little app and press Ctrl+C:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.stage.Stage;
import org.fxmisc.flowless.VirtualizedScrollPane;
import org.fxmisc.richtext.CodeArea;

public class ClipboardCopyNPE extends Application {
    @Override
    public void start(Stage primaryStage) throws Exception {
        CodeArea area = new CodeArea("abc\ndef\nghi");
        VirtualizedScrollPane<CodeArea> vsPane = new VirtualizedScrollPane<>(area);

        area.selectRange(2, 4);
        
        Scene scene = new Scene(vsPane, 400, 400);
        primaryStage.setScene(scene);
        primaryStage.show();
    }
}

The NPE is:

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
	at org.fxmisc.richtext.model.SuperCodec$1.encodeSuper(SuperCodec.java:33)
	at org.fxmisc.richtext.model.SuperCodec$1.encodeSuper(SuperCodec.java:1)
	at org.fxmisc.richtext.model.SuperCodec.encode(SuperCodec.java:15)
	at org.fxmisc.richtext.model.StyledText$2.encode(StyledText.java:94)
	at org.fxmisc.richtext.model.StyledText$2.encode(StyledText.java:1)
	at org.fxmisc.richtext.model.SuperCodec$1.encodeSuper(SuperCodec.java:35)
	at org.fxmisc.richtext.model.SuperCodec$1.encodeSuper(SuperCodec.java:1)
	at org.fxmisc.richtext.model.SuperCodec.encode(SuperCodec.java:15)
	at org.fxmisc.richtext.model.ReadOnlyStyledDocument$3.encode(ReadOnlyStyledDocument.java:139)
	at org.fxmisc.richtext.model.ReadOnlyStyledDocument$3.encode(ReadOnlyStyledDocument.java:1)
	at org.fxmisc.richtext.model.SuperCodec$1.encodeSuper(SuperCodec.java:35)
	at org.fxmisc.richtext.model.SuperCodec$1.encodeSuper(SuperCodec.java:1)
	at org.fxmisc.richtext.model.SuperCodec.encode(SuperCodec.java:15)
	at org.fxmisc.richtext.model.ReadOnlyStyledDocument$2.encode(ReadOnlyStyledDocument.java:116)
	at org.fxmisc.richtext.model.ReadOnlyStyledDocument$2.encode(ReadOnlyStyledDocument.java:1)
	at org.fxmisc.richtext.ClipboardActions.lambda$0(ClipboardActions.java:67)
	at java.util.Optional.ifPresent(Optional.java:159)
	at org.fxmisc.richtext.ClipboardActions.copy(ClipboardActions.java:60)
	at org.fxmisc.richtext.GenericStyledAreaBehavior.lambda$28(GenericStyledAreaBehavior.java:149)
	at org.fxmisc.wellbehaved.event.template.InputMapTemplate.lambda$consume$32(InputMapTemplate.java:107)
	at org.fxmisc.wellbehaved.event.template.PatternActionTemplate.lambda$null$44(InputMapTemplate.java:242)
	at java.util.Optional.map(Optional.java:215)
	at org.fxmisc.wellbehaved.event.template.PatternActionTemplate.lambda$getInputHandlerTemplateMap$45(InputMapTemplate.java:242)
	at org.fxmisc.wellbehaved.event.template.InputHandlerTemplateMap.lambda$sequence$39(InputHandlerTemplateMap.java:25)
	at org.fxmisc.wellbehaved.event.template.InputMapTemplate$1.lambda$null$30(InputMapTemplate.java:92)
	at org.fxmisc.wellbehaved.event.template.InputHandlerTemplateMap.lambda$sequence$39(InputHandlerTemplateMap.java:24)
	at org.fxmisc.wellbehaved.event.template.InputMapTemplate$HandlerTemplateConsumer$1.lambda$accept$29(InputMapTemplate.java:36)
	at org.fxmisc.wellbehaved.event.InputHandler.handle(InputHandler.java:15)
	at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
	at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
	at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
	at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
	at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
	at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
	at javafx.event.Event.fireEvent(Event.java:198)
	at javafx.scene.Scene$KeyHandler.process(Scene.java:3964)
	at javafx.scene.Scene$KeyHandler.access$1800(Scene.java:3910)
	at javafx.scene.Scene.impl_processKeyEvent(Scene.java:2040)
	at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2501)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:217)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:149)
	at java.security.AccessController.doPrivileged(Native Method)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$353(GlassViewEventHandler.java:248)
	at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:247)
	at com.sun.glass.ui.View.handleKeyEvent(View.java:546)
	at com.sun.glass.ui.View.notifyKey(View.java:966)
	at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
	at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
	at java.lang.Thread.run(Thread.java:748)

[JordanMartinez]

Mm… I implemented that class in #553 as a way to make it easier for others to implement custom objects in the area. However, I later realized in #550 (which was created before #553 but merged after it) that such an approach wouldn’t work because sometimes a segment is reduced to an empty one, but isn’t the singleton used in that class. (This is also partly why I proposed #567: once a style is separated from a segment, one can use an empty segment as a singleton because its style isn’t a part of that segment.). That’s not difficult to fix, but I won’t be able to get to it until tomorrow.

[JordanMartinez]

Closed by #578