Change LicenseHeaderStep to be more aggressive about finding the existing copyright years.

Author: nedtwigg

lib/src/main/java/com/diffplug/spotless/generic/LicenseHeaderStep.java

@@ -227,8 +227,9 @@ private String format(String raw) {
 						}
 						return beforeYear + newYear + afterYear + content;
 					} else {
+						String newYear = calculateYearBySearching(raw.substring(0, contentMatcher.start()));
 						// at worst, we just say that it was made today
-						return beforeYear + yearToday + afterYear + content;
+						return beforeYear + newYear + afterYear + content;
 					}
 				}
 			}

testlib/src/test/java/com/diffplug/spotless/generic/LicenseHeaderStepTest.java

@@ -39,9 +39,9 @@ public void parseExistingYear() throws Exception {
 				// has existing
 				.test(hasHeader("This is a fake license, 2007. ACME corp."), hasHeader("This is a fake license, 2007. ACME corp."))
 				// if prefix changes, the year will get set to today
-				.test(hasHeader("This is a license, 2007. ACME corp."), hasHeader("This is a fake license, " + currentYear() + ". ACME corp."))
+				.test(hasHeader("This is a license, 2007. ACME corp."), hasHeader("This is a fake license, 2007. ACME corp."))
 				// if suffix changes, the year will get set to today
-				.test(hasHeader("This is a fake license, 2007. Other corp."), hasHeader("This is a fake license, " + currentYear() + ". ACME corp."));
+				.test(hasHeader("This is a fake license, 2007. Other corp."), hasHeader("This is a fake license, 2007. ACME corp."));
 	}
 
 	@Test
@@ -58,7 +58,7 @@ public void should_apply_license_containing_YEAR_token() throws Throwable {
 				.testUnaffected(hasHeaderYear(currentYear()))
 				.testUnaffected(hasHeaderYear("2003"))
 				.testUnaffected(hasHeaderYear("1990-2015"))
-				.test(hasHeaderYear("Something before license.*/\n/* \n * " + HEADER_WITH_$YEAR, "2003"), hasHeaderYear(currentYear()))
+				.test(hasHeaderYear("Something before license.*/\n/* \n * " + HEADER_WITH_$YEAR, "2003"), hasHeaderYear("2003"))
 				.test(hasHeaderYear(HEADER_WITH_$YEAR + "\n **/\n/* Something after license.", "2003"), hasHeaderYear("2003"))
 				.test(hasHeaderYear("not a year"), hasHeaderYear(currentYear()));
 		// Check with variant