Support a file name field in license headers

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]
+### Added
+* You can now put the filename into a license header template with `$FILE`. ([#1605](https://github.com/diffplug/spotless/pull/1605) fixes [#1147](https://github.com/diffplug/spotless/issues/1147))
 ### Changes
 * We are now opting in to Gradle's new stable configuration cache. ([#1591](https://github.com/diffplug/spotless/pull/1591))
 

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

@@ -142,7 +142,7 @@ public FormatterStep build() {
 					throw new IllegalStateException(yearMode.toString());
 				}
 				return new Runtime(headerLazy.get(), delimiter, yearSeparator, updateYear, skipLinesMatching);
-			}, step -> step::format);
+			}, step -> FormatterFunc.needsFile(step::format));
 		}
 
 		if (contentPattern == null) {
@@ -214,6 +214,8 @@ private static class Runtime implements Serializable {
 		private final boolean updateYearWithLatest;
 		private final boolean licenseHeaderWithRange;
 
+		private static final Pattern FILENAME_PATTERN = Pattern.compile("\\$FILE");
+
 		/** The license that we'd like enforced. */
 		private Runtime(String licenseHeader, String delimiter, String yearSeparator, boolean updateYearWithLatest, @Nullable String skipLinesMatching) {
 			if (delimiter.contains("\n")) {
@@ -266,9 +268,9 @@ private static Optional<String> getYearToken(String licenseHeader) {
 		}
 
 		/** Formats the given string. */
-		private String format(String raw) {
+		private String format(String raw, File file) {
 			if (skipLinesMatching == null) {
-				return addOrUpdateLicenseHeader(raw);
+				return addOrUpdateLicenseHeader(raw, file);
 			} else {
 				String[] lines = raw.split("\n");
 				StringBuilder skippedLinesBuilder = new StringBuilder();
@@ -287,11 +289,11 @@ private String format(String raw) {
 						remainingLinesBuilder.append(line).append('\n');
 					}
 				}
-				return skippedLinesBuilder + addOrUpdateLicenseHeader(remainingLinesBuilder.toString());
+				return skippedLinesBuilder + addOrUpdateLicenseHeader(remainingLinesBuilder.toString(), file);
 			}
 		}
 
-		private String addOrUpdateLicenseHeader(String raw) {
+		private String addOrUpdateLicenseHeader(String raw, File file) {
 			Matcher contentMatcher = delimiterPattern.matcher(raw);
 			if (!contentMatcher.find()) {
 				throw new IllegalArgumentException("Unable to find delimiter regex " + delimiterPattern);
@@ -305,13 +307,14 @@ private String addOrUpdateLicenseHeader(String raw) {
 						return raw;
 					} else {
 						// otherwise we'll have to add the header
-						return yearSepOrFull + content;
+						return replaceFileName(yearSepOrFull, file) + content;
 					}
 				} else {
 					// the yes year case is a bit harder
 					int beforeYearIdx = raw.indexOf(beforeYear);
 					int afterYearIdx = raw.indexOf(afterYear, beforeYearIdx + beforeYear.length() + 1);
 
+					String header;
 					if (beforeYearIdx >= 0 && afterYearIdx >= 0 && afterYearIdx + afterYear.length() <= contentMatcher.start()) {
 						// and also ends with exactly the right header, so it's easy to parse the existing year
 						String existingYear = raw.substring(beforeYearIdx + beforeYear.length(), afterYearIdx);
@@ -323,12 +326,13 @@ private String addOrUpdateLicenseHeader(String raw) {
 								return raw;
 							}
 						}
-						return beforeYear + newYear + afterYear + content;
+						header = beforeYear + newYear + afterYear;
 					} else {
 						String newYear = calculateYearBySearching(raw.substring(0, contentMatcher.start()));
 						// at worst, we just say that it was made today
-						return beforeYear + newYear + afterYear + content;
+						header = beforeYear + newYear + afterYear;
 					}
+					return replaceFileName(header, file) + content;
 				}
 			}
 		}
@@ -421,6 +425,10 @@ private String setLicenseHeaderYearsFromGitHistory(String raw, File file) throws
 			return beforeYear + yearRange + afterYear + raw.substring(contentMatcher.start());
 		}
 
+		private String replaceFileName(String header, File file) {
+			return FILENAME_PATTERN.matcher(header).replaceAll(file.getName());
+		}
+
 		private static String parseYear(String cmd, File file) throws IOException {
 			String fullCmd = cmd + " -- " + file.getAbsolutePath();
 			ProcessBuilder builder = new ProcessBuilder().directory(file.getParentFile());

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]
+### Added
+* You can now put the filename into a license header template with `$FILE`. ([#1605](https://github.com/diffplug/spotless/pull/1605) fixes [#1147](https://github.com/diffplug/spotless/issues/1147))
 
 ## [6.16.0] - 2023-02-27
 ### Added

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]
+### Added
+* You can now put the filename into a license header template with `$FILE`. ([#1605](https://github.com/diffplug/spotless/pull/1605) fixes [#1147](https://github.com/diffplug/spotless/issues/1147))
 
 ## [2.34.0] - 2023-02-27
 ### Added

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

@@ -28,13 +28,16 @@
 import com.diffplug.spotless.ResourceHarness;
 import com.diffplug.spotless.SerializableEqualityTester;
 import com.diffplug.spotless.StepHarness;
+import com.diffplug.spotless.StepHarnessWithFile;
 import com.diffplug.spotless.generic.LicenseHeaderStep.YearMode;
 
 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-$YEAR. ACME corp.";
+	private static final String HEADER_WITH_$FILE = "This is a fake license, $FILE. ACME corp.";
+	private static final String HEADER_WITH_$YEAR_$FILE = "This is a fake license, $FILE, $YEAR. ACME corp.";
 
 	@Test
 	void parseExistingYear() throws Exception {
@@ -163,6 +166,16 @@ private String hasHeaderWithRangeAndWithYearTo(String toYear) throws IOException
 		return hasHeaderYear(HEADER_WITH_RANGE_TO_$YEAR, toYear);
 	}
 
+	private String hasHeaderFileName(String license, String fileName) throws IOException {
+		return header(license).replace("$FILE", fileName) + getTestResource(FILE_NO_LICENSE);
+	}
+
+	private String hasHeaderYearFileName(String license, String year, String fileName) throws IOException {
+		return header(license)
+				.replace("$YEAR", year)
+				.replace("$FILE", fileName) + getTestResource(FILE_NO_LICENSE);
+	}
+
 	private static String currentYear() {
 		return String.valueOf(YearMonth.now().getYear());
 	}
@@ -250,4 +263,21 @@ void should_preserve_year_for_license_with_address() throws Throwable {
 				hasHeader(licenceWithAddress().replace("$YEAR", "2015").replace("FooBar Inc. All", "FooBar Inc.  All")),
 				hasHeader(licenceWithAddress().replace("$YEAR", "2015")));
 	}
+
+	@Test
+	void should_apply_license_containing_filename_token() throws Exception {
+		FormatterStep step = LicenseHeaderStep.headerDelimiter(header(HEADER_WITH_$FILE), package_).build();
+		StepHarnessWithFile.forStep(this, step)
+				.test(new File("Test.java"), getTestResource(FILE_NO_LICENSE), hasHeaderFileName(HEADER_WITH_$FILE, "Test.java"));
+	}
+
+	@Test
+	void should_apply_license_containing_YEAR_filename_token() throws Exception {
+		FormatterStep step = LicenseHeaderStep.headerDelimiter(header(HEADER_WITH_$YEAR_$FILE), package_).build();
+		StepHarnessWithFile.forStep(this, step)
+				.test(
+						new File("Test.java"),
+						getTestResource(FILE_NO_LICENSE),
+						hasHeaderYearFileName(HEADER_WITH_$YEAR_$FILE, currentYear(), "Test.java"));
+	}
 }