[Bug 500475] Guard 'doubleClickSelection' with 'doubleClickEnabled'.

The field 'doubleClickSelection' might be accessed only in case
'doubleClickEnabled' is true. Otherwise it will be null and NPE is the
result. In case 'doubleClickEnabled = false" 'selectionAnchor' will
already have the correct value.

Added snippet to reproduce bug.

Change-Id: Id5743435fd231dc03df8376122495a51b9bcb662
Signed-off-by: Arne Deutsch <arne@idedeluxe.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/org.eclipse.swt.tests/BugSnippets/Bug500475_StyledText_NPE_on_selection_drag.java b/tests/org.eclipse.swt.tests/BugSnippets/Bug500475_StyledText_NPE_on_selection_drag.java
new file mode 100644
index 0000000000..11d329b52e
--- /dev/null
+++ b/tests/org.eclipse.swt.tests/BugSnippets/Bug500475_StyledText_NPE_on_selection_drag.java
@@ -0,0 +1,34 @@
+
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.custom.StyledText;
+import org.eclipse.swt.layout.FillLayout;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Shell;
+
+/**
+ * Description: StyledText NPE on selection drag.
+ * Steps to reproduce: Double click in the text but do not release the mouse button after second click. Drag around
+ *     the text such that scrolling of the text widget does happen.
+ * Expected results: No exceptions should be raised.
+ * Actual results: Application dies because of NPE.
+ */
+public class Bug500475_StyledText_NPE_on_selection_drag {
+
+	public static void main(String[] args) {
+		Display display = new Display();
+		final Shell shell = new Shell(display);
+		shell.setSize(200, 200);
+		shell.setLayout(new FillLayout());
+
+		StyledText text = new StyledText(shell, SWT.BORDER);
+		text.setDoubleClickEnabled(false); // exception does happen only if this flag is 'false'
+		text.setText("This is some dummy text. We need enough text to have the scroll bars appear.");
+
+		shell.open();
+		while (!shell.isDisposed()) {
+			if (!display.readAndDispatch())
+				display.sleep();
+		}
+		display.dispose();
+	}
+}