Revert the change to console formatting in x.26.0 (#485).

CHANGES.md

@@ -7,6 +7,8 @@ You might be looking for:
 
 ### Version 1.27.0-SNAPSHOT - TBD (javadoc [lib](https://diffplug.github.io/spotless/javadoc/spotless-lib/snapshot/) [lib-extra](https://diffplug.github.io/spotless/javadoc/spotless-lib-extra/snapshot/), [snapshot repo](https://oss.sonatype.org/content/repositories/snapshots/com/diffplug/spotless/))
 
+* Revert the change in console display of errors from 1.26.0 ([#485](https://github.com/diffplug/spotless/pull/485)) because [of these problems](https://github.com/diffplug/spotless/pull/485#issuecomment-552925932).
+
 ### Version 1.26.0 - November 11th 2019 (javadoc [lib](https://diffplug.github.io/spotless/javadoc/spotless-lib/1.26.0/) [lib-extra](https://diffplug.github.io/spotless/javadoc/spotless-lib-extra/1.26.0/), artifact [lib]([jcenter](https://bintray.com/diffplug/opensource/spotless-lib), [lib-extra]([jcenter](https://bintray.com/diffplug/opensource/spotless-lib-extra)))
 
 * Fix project URLs in poms. ([#478](https://github.com/diffplug/spotless/pull/478))

README.md

@@ -92,7 +92,6 @@ Once someone has filled in one square of the formatter/build system matrix, it's
 - Thanks to [Simon Gamma](https://github.com/simschla) for [adding support for npm-based formatters](https://github.com/diffplug/spotless/pull/283), including `prettier` and `tsfmt`.
 - Thanks to [Frank Vennemeyer](https://github.com/fvgh) for [Groovy support via greclipse](https://github.com/diffplug/spotless/issues/13), [C++ support via CDT](https://github.com/diffplug/spotless/issues/232), [XML support via WTP](https://github.com/diffplug/spotless/pull/241) and a huge body of work with other eclipse-based formatters.
 - Thanks to [Konstantin Lutovich](https://github.com/lutovich) for [implementing the maven plugin](https://github.com/diffplug/spotless/pull/188).
-- Thanks to [Vladimir Sitnikov](https://github.com/vlsi) for [improving our format error messages](https://github.com/diffplug/spotless/pull/485).
 - Thanks to [Kevin Brooks](https://github.com/k-brooks) for [updating all eclipse-based formatters to 4.13](https://github.com/diffplug/spotless/pull/482).
 - Thanks to [Joan Goyeau](https://github.com/joan38) for [fixing scalafmt integration](https://github.com/diffplug/spotless/pull/260).
 - Thanks to [Nick Sutcliffe](https://github.com/nsutcliffe) for [fixing scalafmt post-2.0](https://github.com/diffplug/spotless/pull/416).

lib-extra/src/main/java/com/diffplug/spotless/extra/integration/DiffMessageFormatter.java

@@ -18,18 +18,19 @@
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
-import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.List;
 import java.util.ListIterator;
 import java.util.Objects;
 
+import org.eclipse.jgit.diff.DiffFormatter;
 import org.eclipse.jgit.diff.EditList;
-import org.eclipse.jgit.diff.HistogramDiff;
+import org.eclipse.jgit.diff.MyersDiff;
 import org.eclipse.jgit.diff.RawText;
 import org.eclipse.jgit.diff.RawTextComparator;
 
+import com.diffplug.common.base.CharMatcher;
 import com.diffplug.common.base.Errors;
 import com.diffplug.common.base.Preconditions;
 import com.diffplug.common.base.Splitter;
@@ -138,10 +139,7 @@ private void addFile(String arg) {
 
 		// then we'll print the rest that can fit
 		ListIterator<String> iter = lines.listIterator(Math.min(MIN_LINES_PER_FILE, lines.size()));
-		// lines.size() - iter.nextIndex() == 1 means "just one line left", and we just print the line
-		// instead of "1 more lines that didn't fit"
-		while (iter.hasNext() &&
-				(numLines < MAX_CHECK_MESSAGE_LINES || lines.size() - iter.nextIndex() == 1)) {
+		while (iter.hasNext() && numLines < MAX_CHECK_MESSAGE_LINES) {
 			addIntendedLine(DIFF_INDENT, iter.next());
 		}
 
@@ -170,30 +168,70 @@ private void addIntendedLine(String indent, String line) {
 	 * sequence (\n, \r, \r\n).
 	 */
 	private static String diff(Builder builder, File file) throws IOException {
-		Charset encoding = builder.formatter.getEncoding();
-		String raw = new String(Files.readAllBytes(file.toPath()), encoding);
+		String raw = new String(Files.readAllBytes(file.toPath()), builder.formatter.getEncoding());
 		String rawUnix = LineEnding.toUnix(raw);
 		String formattedUnix;
 		if (builder.isPaddedCell) {
 			formattedUnix = PaddedCell.check(builder.formatter, file, rawUnix).canonical();
 		} else {
 			formattedUnix = builder.formatter.compute(rawUnix, file);
 		}
-		String formatted = builder.formatter.computeLineEndings(formattedUnix, file);
-		return visualizeDiff(raw, formatted);
+
+		if (rawUnix.equals(formattedUnix)) {
+			// the formatting is fine, so it's a line-ending issue
+			String formatted = builder.formatter.computeLineEndings(formattedUnix, file);
+			return diffWhitespaceLineEndings(raw, formatted, false, true);
+		} else {
+			return diffWhitespaceLineEndings(rawUnix, formattedUnix, true, false);
+		}
 	}
 
-	private static String visualizeDiff(String raw, String formattedBytes) throws IOException {
-		RawText a = new RawText(raw.getBytes(StandardCharsets.UTF_8));
-		RawText b = new RawText(formattedBytes.getBytes(StandardCharsets.UTF_8));
-		EditList edits = new HistogramDiff().diff(RawTextComparator.DEFAULT, a, b);
+	/**
+	 * Returns a git-style diff between the two unix strings.
+	 *
+	 * Output has no trailing newlines.
+	 *
+	 * Boolean args determine whether whitespace or line endings will be visible.
+	 */
+	private static String diffWhitespaceLineEndings(String dirty, String clean, boolean whitespace, boolean lineEndings) throws IOException {
+		dirty = visibleWhitespaceLineEndings(dirty, whitespace, lineEndings);
+		clean = visibleWhitespaceLineEndings(clean, whitespace, lineEndings);
+
+		RawText a = new RawText(dirty.getBytes(StandardCharsets.UTF_8));
+		RawText b = new RawText(clean.getBytes(StandardCharsets.UTF_8));
+		EditList edits = new EditList();
+		edits.addAll(MyersDiff.INSTANCE.diff(RawTextComparator.DEFAULT, a, b));
+
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
-		// defaultCharset is here so the formatter could select "fancy" or "simple"
-		// characters for whitespace visualization based on the capabilities of the console
-		// For instance, if the app is running with file.encoding=ISO-8859-1, then
-		// the console can't encode fancy whitespace characters, and the formatter would
-		// resort to simple "\\r", "\\n", and so on
-		new WriteSpaceAwareDiffFormatter(out, Charset.defaultCharset()).format(edits, a, b);
-		return new String(out.toByteArray(), StandardCharsets.UTF_8);
+		try (DiffFormatter formatter = new DiffFormatter(out)) {
+			formatter.format(edits, a, b);
+		}
+		String formatted = out.toString(StandardCharsets.UTF_8.name());
+
+		// we don't need the diff to show this, since we display newlines ourselves
+		formatted = formatted.replace("\\ No newline at end of file\n", "");
+		return NEWLINE_MATCHER.trimTrailingFrom(formatted);
 	}
+
+	private static final CharMatcher NEWLINE_MATCHER = CharMatcher.is('\n');
+
+	/**
+	 * Makes the whitespace and/or the lineEndings visible.
+	 *
+	 * MyersDiff wants inputs with only unix line endings.  So this ensures that that is the case.
+	 */
+	private static String visibleWhitespaceLineEndings(String input, boolean whitespace, boolean lineEndings) {
+		if (whitespace) {
+			input = input.replace(' ', MIDDLE_DOT).replace("\t", "\\t");
+		}
+		if (lineEndings) {
+			input = input.replace("\n", "\\n\n").replace("\r", "\\r");
+		} else {
+			// we want only \n, so if we didn't replace them above, we'll replace them here.
+			input = input.replace("\r", "");
+		}
+		return input;
+	}
+
+	private static final char MIDDLE_DOT = '\u00b7';
 }

plugin-gradle/CHANGES.md

@@ -2,6 +2,8 @@
 
 ### Version 3.27.0-SNAPSHOT - TBD ([javadoc](https://diffplug.github.io/spotless/javadoc/snapshot/), [snapshot](https://oss.sonatype.org/content/repositories/snapshots/com/diffplug/spotless/spotless-plugin-gradle/))
 
+* Revert the change in console display of errors from 3.26.0 ([#485](https://github.com/diffplug/spotless/pull/485)) because [of these problems](https://github.com/diffplug/spotless/pull/485#issuecomment-552925932).
+
 ### Version 3.26.0 - November 11th 2019 ([javadoc](https://diffplug.github.io/spotless/javadoc/spotless-plugin-gradle/3.26.0/), [jcenter](https://bintray.com/diffplug/opensource/spotless-plugin-gradle/3.26.0))
 
 * Fix project URLs in poms. ([#478](https://github.com/diffplug/spotless/pull/478))