Integrate paddedcell into maven.

Author: nedtwigg

plugin-maven/CHANGES.md

@@ -5,6 +5,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 ## [Unreleased]
 ### Added
 * Support for google-java-format 1.8 (requires you to run build on Java 11) ([#562](https://github.com/diffplug/spotless/issues/562))
+* `mvn spotless:apply` is now guaranteed to be idempotent, even if some of the formatters are not.  See [`PADDEDCELL.md` for details](https://github.com/diffplug/spotless/blob/master/PADDEDCELL.md) if you're curious. ([#565](https://github.com/diffplug/spotless/pull/565))
 * Updated a bunch of dependencies, most notably jgit `5.5.0.201909110433-r` -> `5.7.0.202003110725-r`. ([#564](https://github.com/diffplug/spotless/pull/564))
 
 ## [1.30.0] - 2020-04-10

plugin-maven/src/main/java/com/diffplug/spotless/maven/SpotlessApplyMojo.java

@@ -24,6 +24,7 @@
 import org.apache.maven.plugins.annotations.Parameter;
 
 import com.diffplug.spotless.Formatter;
+import com.diffplug.spotless.PaddedCell;
 
 /**
  * Performs formatting of all source files according to configured formatters.
@@ -42,7 +43,10 @@ protected void process(List<File> files, Formatter formatter) throws MojoExecuti
 
 		for (File file : files) {
 			try {
-				formatter.applyTo(file);
+				PaddedCell.DirtyState dirtyState = PaddedCell.calculateDirtyState(formatter, file);
+				if (!dirtyState.isClean() && !dirtyState.didNotConverge()) {
+					dirtyState.writeCanonicalTo(file);
+				}
 			} catch (IOException e) {
 				throw new MojoExecutionException("Unable to format file " + file, e);
 			}

plugin-maven/src/main/java/com/diffplug/spotless/maven/SpotlessCheckMojo.java

@@ -26,6 +26,7 @@
 import org.apache.maven.plugins.annotations.Parameter;
 
 import com.diffplug.spotless.Formatter;
+import com.diffplug.spotless.PaddedCell;
 import com.diffplug.spotless.extra.integration.DiffMessageFormatter;
 
 /**
@@ -48,7 +49,8 @@ protected void process(List<File> files, Formatter formatter) throws MojoExecuti
 		List<File> problemFiles = new ArrayList<>();
 		for (File file : files) {
 			try {
-				if (!formatter.isClean(file)) {
+				PaddedCell.DirtyState dirtyState = PaddedCell.calculateDirtyState(formatter, file);
+				if (!dirtyState.isClean() && !dirtyState.didNotConverge()) {
 					problemFiles.add(file);
 				}
 			} catch (IOException e) {
@@ -59,7 +61,6 @@ protected void process(List<File> files, Formatter formatter) throws MojoExecuti
 		if (!problemFiles.isEmpty()) {
 			throw new MojoExecutionException(DiffMessageFormatter.builder()
 					.runToFix("Run 'mvn spotless:apply' to fix these violations.")
-					.isPaddedCell(false)
 					.formatter(formatter)
 					.problemFiles(problemFiles)
 					.getMessage());