[Eclipse] Index out of bounds while drawing ghost text

[joaodinissf]

Describe the bug
In certain cases, Tabby makes calls to org.eclipse.swt.custom.StyledText.getLocationAtOffset(int) in which the offset argument is greater than getCharCount(). This causes an java.lang.IllegalArgumentException: Index out of bounds exception to be thrown here.

This exception may occasionally cause ghost text to be improperly rendered.

I have observed this exception occur as a result of these two function calls, at lines 331 and 416 of InlineCompletionRenderer.java:

• tabby/clients/eclipse/plugin/src/com/tabbyml/tabby4eclipse/inlineCompletion/InlineCompletionRenderer.java

  Line 331 in 096dd20

  Point location = widget.getLocationAtOffset(offset);

• tabby/clients/eclipse/plugin/src/com/tabbyml/tabby4eclipse/inlineCompletion/InlineCompletionRenderer.java

  Line 416 in 096dd20

  Point location = widget.getLocationAtOffset(offset);

Information about your version
Tabby for Eclipse: v0.0.2.26

Information about your GPU
N/A

Additional context

Instructions to reproduce this bug

1. Launch the Eclipse IDE with the Tabby, create an empty project
2. Create a file with a few lines of text (see, for example, the video attached below)
3. Place the cursor at an empty line at the very end of the file
4. Press the BACKSPACE and/or ENTER keys a few times in quick succession: this will trigger a re-drawing of the ghost text in such a way that this bug occurs

Video showing the bug

indexOoB.mp4

Sample stack trace 1

java.lang.IllegalArgumentException: Index out of bounds
	at org.eclipse.swt.SWT.error(SWT.java:4903)
	at org.eclipse.swt.SWT.error(SWT.java:4837)
	at org.eclipse.swt.SWT.error(SWT.java:4808)
	at org.eclipse.swt.custom.StyledText.getLocationAtOffset(StyledText.java:4015)
	at com.tabbyml.tabby4eclipse.inlineCompletion.InlineCompletionRenderer$InlineCompletionItemPainter.lambda$5(InlineCompletionRenderer.java:331)
	at com.tabbyml.tabby4eclipse.inlineCompletion.InlineCompletionRenderer$InlineCompletionItemPainter.lambda$2(Unknown Source)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
	at com.tabbyml.tabby4eclipse.inlineCompletion.InlineCompletionRenderer$InlineCompletionItemPainter.paintControl(Unknown Source)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:247)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:91)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4285)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1160)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1184)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1169)
	at org.eclipse.swt.widgets.Composite.WM_PAINT(Composite.java:1540)
	at org.eclipse.swt.widgets.Control.windowProc(Control.java:4769)
	at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:340)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:5050)
	at org.eclipse.swt.internal.win32.OS.DispatchMessage(Native Method)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3671)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1151)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:339)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1042)
	at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:152)
	at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:639)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:339)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:546)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:173)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:152)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:208)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:143)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:109)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:439)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:271)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:668)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:605)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1481)
	at org.eclipse.equinox.launcher.Main.main(Main.java:1454)

Sample stack trace 2

java.lang.IllegalArgumentException: Index out of bounds
	at org.eclipse.swt.SWT.error(SWT.java:4903)
	at org.eclipse.swt.SWT.error(SWT.java:4837)
	at org.eclipse.swt.SWT.error(SWT.java:4808)
	at org.eclipse.swt.custom.StyledText.getLocationAtOffset(StyledText.java:4016)
	at com.tabbyml.tabby4eclipse.inlineCompletion.InlineCompletionRenderer$InlineCompletionItemPainter.lambda$7(InlineCompletionRenderer.java:416)
	at com.tabbyml.tabby4eclipse.inlineCompletion.InlineCompletionRenderer$InlineCompletionItemPainter.lambda$2(InlineCompletionRenderer.java:129)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	at com.tabbyml.tabby4eclipse.inlineCompletion.InlineCompletionRenderer$InlineCompletionItemPainter.paintControl(InlineCompletionRenderer.java:128)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:247)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:91)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4326)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1174)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1198)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1183)
	at org.eclipse.swt.widgets.Composite.WM_PAINT(Composite.java:1544)
	at org.eclipse.swt.widgets.Control.windowProc(Control.java:4784)
	at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:342)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:5091)
	at org.eclipse.swt.internal.win32.OS.DispatchMessage(Native Method)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3710)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1151)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:339)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1042)
	at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:153)
	at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:639)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:339)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:546)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:173)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:152)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:208)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:143)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:109)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:439)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:271)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:668)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:605)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1481)
	at org.eclipse.equinox.launcher.Main.main(Main.java:1454)