Fix license header bug for years in range (#840)

Author: nedtwigg

Diff for: CHANGES.md

@@ -10,6 +10,8 @@ This document is intended for Spotless developers.
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Fix license header bug for years in range ([#840](https://github.com/diffplug/spotless/pull/840)).
 
 ## [2.13.1] - 2021-04-10
 ### Changed

Diff for: lib/src/main/java/com/diffplug/spotless/generic/LicenseHeaderStep.java

@@ -151,6 +151,7 @@ private static class Runtime implements Serializable {
 		private final @Nullable String beforeYear;
 		private final @Nullable String afterYear;
 		private final boolean updateYearWithLatest;
+		private final boolean licenseHeaderWithRange;
 
 		/** The license that we'd like enforced. */
 		private Runtime(String licenseHeader, String delimiter, String yearSeparator, boolean updateYearWithLatest) {
@@ -166,18 +167,28 @@ private Runtime(String licenseHeader, String delimiter, String yearSeparator, bo
 
 			Optional<String> yearToken = getYearToken(licenseHeader);
 			if (yearToken.isPresent()) {
-				yearToday = String.valueOf(YearMonth.now().getYear());
+				this.yearToday = String.valueOf(YearMonth.now().getYear());
 				int yearTokenIndex = licenseHeader.indexOf(yearToken.get());
-				beforeYear = licenseHeader.substring(0, yearTokenIndex);
-				afterYear = licenseHeader.substring(yearTokenIndex + yearToken.get().length());
-				yearSepOrFull = yearSeparator;
+				this.beforeYear = licenseHeader.substring(0, yearTokenIndex);
+				this.afterYear = licenseHeader.substring(yearTokenIndex + yearToken.get().length());
+				this.yearSepOrFull = yearSeparator;
 				this.updateYearWithLatest = updateYearWithLatest;
+
+				boolean hasHeaderWithRange = false;
+				int yearPlusSep = 4 + yearSeparator.length();
+				if (beforeYear.endsWith(yearSeparator) && yearTokenIndex > yearPlusSep) {
+					// year from in range
+					String yearFrom = licenseHeader.substring(yearTokenIndex - yearPlusSep, yearTokenIndex).substring(0, 4);
+					hasHeaderWithRange = YYYY.matcher(yearFrom).matches();
+				}
+				this.licenseHeaderWithRange = hasHeaderWithRange;
 			} else {
-				yearToday = null;
-				beforeYear = null;
-				afterYear = null;
+				this.yearToday = null;
+				this.beforeYear = null;
+				this.afterYear = null;
 				this.yearSepOrFull = licenseHeader;
 				this.updateYearWithLatest = false;
+				this.licenseHeaderWithRange = false;
 			}
 		}
 
@@ -243,7 +254,11 @@ private String calculateYearExact(String parsedYear) {
 				return parsedYear;
 			} else if (YYYY.matcher(parsedYear).matches()) {
 				if (updateYearWithLatest) {
-					return parsedYear + yearSepOrFull + yearToday;
+					if (licenseHeaderWithRange) {
+						return yearToday;
+					} else {
+						return parsedYear + yearSepOrFull + yearToday;
+					}
 				} else {
 					// it's already good as a single year
 					return parsedYear;
@@ -266,7 +281,15 @@ private String calculateYearBySearching(String content) {
 				} else {
 					secondYear = null;
 				}
-				return secondYear == null ? firstYear : firstYear + yearSepOrFull + secondYear;
+				if (secondYear == null) {
+					return firstYear;
+				} else {
+					if (licenseHeaderWithRange) {
+						return secondYear;
+					} else {
+						return firstYear + yearSepOrFull + secondYear;
+					}
+				}
 			} else {
 				System.err.println("Can't parse copyright year '" + content + "', defaulting to " + yearToday);
 				// couldn't recognize the year format

Diff for: plugin-gradle/CHANGES.md

@@ -3,6 +3,8 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `3.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Fix license header bug for years in range ([#840](https://github.com/diffplug/spotless/pull/840)).
 
 ## [5.12.0] - 2021-04-10
 ### Added

Diff for: plugin-maven/CHANGES.md

@@ -3,6 +3,8 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Fix license header bug for years in range ([#840](https://github.com/diffplug/spotless/pull/840)).
 
 ## [2.10.0] - 2021-04-10
 ### Added

Diff for: testlib/src/test/java/com/diffplug/spotless/generic/LicenseHeaderStepTest.java

@@ -32,6 +32,7 @@ public class LicenseHeaderStepTest extends ResourceHarness {
 	private static final String FILE_NO_LICENSE = "license/FileWithoutLicenseHeader.test";
 	private static final String package_ = "package ";
 	private static final String HEADER_WITH_$YEAR = "This is a fake license, $YEAR. ACME corp.";
+	private static final String HEADER_WITH_RANGE_TO_$YEAR = "This is a fake license with range, 2009-$YEAR. ACME corp.";
 
 	@Test
 	public void parseExistingYear() throws Exception {
@@ -137,6 +138,10 @@ private String hasHeaderYear(String years) throws IOException {
 		return hasHeaderYear(HEADER_WITH_$YEAR, years);
 	}
 
+	private String hasHeaderWithRangeAndWithYearTo(String toYear) throws IOException {
+		return hasHeaderYear(HEADER_WITH_RANGE_TO_$YEAR, toYear);
+	}
+
 	private static String currentYear() {
 		return String.valueOf(YearMonth.now().getYear());
 	}
@@ -201,4 +206,10 @@ protected FormatterStep create() {
 			}
 		}.testEquals();
 	}
+
+	@Test
+	public void should_apply_license_containing_YEAR_token_in_range() throws Throwable {
+		FormatterStep step = LicenseHeaderStep.headerDelimiter(header(HEADER_WITH_RANGE_TO_$YEAR), package_).withYearMode(YearMode.UPDATE_TO_TODAY).build();
+		StepHarness.forStep(step).test(hasHeaderWithRangeAndWithYearTo("2015"), hasHeaderWithRangeAndWithYearTo(currentYear()));
+	}
 }