VersionUtils.compare: fix bug with suffixes

When comparing e.g. "1" versus "a", the logic was stripping the "1" as
leading and ultimately comparing "" with "a". This comparison happened
to give the same result, because both "" and "1" compare less than "a",
but for other strings like "%" which comes before the digits, the
behavior differs.

Author: ctrueden

src/main/java/org/scijava/util/VersionUtils.java

@@ -146,15 +146,18 @@ private static String[] splitDots(final String s) {
 	/** Compares one token of a multi-token version string. */
 	private static int compareToken(final String t1, final String t2) {
 		final int i1 = digitIndex(t1), i2 = digitIndex(t2);
+		String suffix1 = t1, suffix2 = t2;
 		if (i1 > 0 && i2 > 0) {
 			// Versions start with digits; compare them numerically.
 			final long d1 = Long.parseLong(t1.substring(0, i1));
 			final long d2 = Long.parseLong(t2.substring(0, i2));
 			if (d1 < d2) return -1;
 			if (d1 > d2) return 1;
+			suffix1 = t1.substring(i1);
+			suffix2 = t2.substring(i2);
 		}
-		// Compare remaining characters lexicographically.
-		return t1.substring(i1).compareTo(t2.substring(i2));
+		// Compare lexicographically.
+		return suffix1.compareTo(suffix2);
 	}
 
 	/** Gets the subsequent index to all the given string's leading digits. */

src/test/java/org/scijava/util/VersionUtilsTest.java

@@ -88,6 +88,7 @@ public void testCompare() {
 
 		// Check weird stuff.
 		assertTrue(VersionUtils.compare("1", "a") < 0);
+		assertTrue(VersionUtils.compare("1", "%") > 0);
 		assertTrue(VersionUtils.compare("", "1") < 0);
 		assertTrue(VersionUtils.compare("1", "1.") < 0);
 		assertTrue(VersionUtils.compare("", ".") < 0);