Fix behaviour of ConsoleReader.setBuffer() if cursor is not at end of…

… line

If the cursor is not at the end of the line and the old and new
buffers have a common prefix then setBuffer will call backspace
with an incorrect argument and the buffer will be mangled.  This
patch fixes the bug.

Signed-off-by: Charles Oliver Nutter <headius@headius.com>

src/main/java/jline/ConsoleReader.java

@@ -1006,7 +1006,11 @@ private final void setBuffer(final String buffer) throws IOException {
             }
         }
 
-        int diff = buf.buffer.length() - sameIndex;
+        int diff = buf.cursor - sameIndex;
+        if (diff < 0) { // we can't backspace here so try from the end of the buffer
+                moveToEnd();
+                diff = buf.buffer.length() - sameIndex;
+        }
 
         backspace(diff); // go back for the differences
         killLine(); // clear to the end of the line

src/test/java/jline/TestHistory.java

@@ -29,6 +29,7 @@ public void testSingleHistory() throws Exception {
         assertBuffer("", b);
 
         assertBuffer("test line 5", b = b.op(ConsoleReader.PREV_HISTORY));
+        assertBuffer("test line 5", b = b.op(ConsoleReader.PREV_CHAR));
         assertBuffer("test line 4", b = b.op(ConsoleReader.PREV_HISTORY));
         assertBuffer("test line 5", b = b.op(ConsoleReader.NEXT_HISTORY));
         assertBuffer("test line 4", b = b.op(ConsoleReader.PREV_HISTORY));