Expose conflicting files in CheckoutConflictException

Change-Id: I5b3b7b0633354d5ccf0c6c320c0df9c93fdf8eeb
Signed-off-by: Ned Twigg <ned.twigg@diffplug.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/DirCacheCheckoutTest.java

 			fail("didn't get the expected exception");
 		} catch (CheckoutConflictException e) {
 			assertConflict("foo");
+			assertEquals("foo", e.getConflictingFiles()[0]);
 			assertWorkDir(mkmap("foo", "bar", "other", "other"));
 			assertIndex(mk("other"));
 		}
 			assertWorkDir(mkmap("a", "a", "b/c", "b/c", "d", "d", "e/f",
 					"e/f", "e/g", "e/g3"));
 			assertConflict("e/g");
+			assertEquals("e/g", e.getConflictingFiles()[0]);
 		}
 	}
 

org.eclipse.jgit/src/org/eclipse/jgit/errors/CheckoutConflictException.java

 public class CheckoutConflictException extends IOException {
 	private static final long serialVersionUID = 1L;
 
+	private final String[] conflicting;
+
 	/**
 	 * Construct a CheckoutConflictException for the specified file
 	 *
 	 */
 	public CheckoutConflictException(String file) {
 		super(MessageFormat.format(JGitText.get().checkoutConflictWithFile, file));
+		conflicting = new String[] { file };
 	}
 
 	/**
 	 */
 	public CheckoutConflictException(String[] files) {
 		super(MessageFormat.format(JGitText.get().checkoutConflictWithFiles, buildList(files)));
+		conflicting = files;
+	}
+
+	/**
+	 * @return the relative paths of the conflicting files (relative to the
+	 *         working directory root).
+	 * @since 4.4
+	 */
+	public String[] getConflictingFiles() {
+		return conflicting;
 	}
 
 	private static String buildList(String[] files) {