#45 StringIndexOutOfBoundsException when pressing Escape

[Iulian Dragos]

On Windows (using the Scala interpreter):

* type one char (or more) on an empty command line
* go left one char with cursor keys
* press escape

Stack trace:
Exception in thread "Thread-1" java.lang.StringIndexOutOfBoundsException:
String index out of range: -1
at java.lang.AbstractStringBuilder.deleteCharAt(AbstractStringBuilder.java:770)
at java.lang.StringBuffer.deleteCharAt(StringBuffer.java:382)
at jline.ConsoleReader.killLine(ConsoleReader.java:742)
at jline.ConsoleReader.readLine(ConsoleReader.java:569)
at jline.ConsoleReader.readLine(ConsoleReader.java:416)
at scala.tools.nsc.interpreter.JLineReader.readLine(JLineReader.scala:24)
at scala.tools.nsc.InterpreterLoop$$anonfun$1.apply(InterpreterLoop.scala:135)
..

[Charles Oliver Nutter]

I could not reproduce this in JRuby's console (jirb) on OS X. Do not have Windows handy right now.

[Vitaliy Garnashevich]

Here is a test for Windows, to detect this bug:

--- ConsoleReaderTest.java Fri Mar 9 17:04:54 2007
+++ ConsoleReaderTest.java Wed Jul 14 14:56:10 2010
@@ -134,6 +134,19 @@
assertWindowsKeyBehavior("oops", characters);
}

+ public void testClearLineWhenNotAtEndOnWindowsTerminal() throws Exception {
+ // test only works on Windows
+ if (!(Terminal.getTerminal() instanceof WindowsTerminal))
+ return;
+
+ char[] characters = new char[] { '1', '2', '3',
+ WindowsTerminal.SPECIAL_KEY_INDICATOR,
+ WindowsTerminal.LEFT_ARROW_KEY,
+ WindowsTerminal.SPECIAL_KEY_INDICATOR,
+ WindowsTerminal.ESCAPE_KEY, '4', '5', '\r', '\n' };
+ assertWindowsKeyBehavior("45", characters);
+ }
+
private void assertWindowsKeyBehavior(String expected, char[] input)
throws Exception {
StringBuffer buffer = new StringBuffer();

[Vitaliy Garnashevich]

Here is a patch to fix this:

--- ConsoleReader.java Fri Feb 22 01:59:14 2008
+++ ConsoleReader.java Wed Jul 14 15:03:54 2010
@@ -599,7 +599,7 @@
break;

case CLEAR_LINE:
- moveInternal(-(buf.buffer.length()));
+ moveInternal(-buf.cursor);
killLine();
break;