add support for prettier-plugins to maven-builds and document in README

Author: simschla

plugin-maven/README.md

@@ -287,13 +287,21 @@ To use prettier, you first have to specify the files that you want it to apply t
       </includes>
 
       <prettier>
-        <!-- Specify either simple prettier version (1.19.0 is max supported,
-             which is also default) or whole devDependencies -->
+        <!-- Specify at most one of the following 3 configs: either 'prettierVersion' (2.0.5 is default), 'devDependencies' or 'devDependencyProperties'  -->
         <prettierVersion>1.19.0</prettierVersion>
         <devDependencies>
             <prettier>1.19.0</prettier>
         </devDependencies>
-
+        <devDependencyProperties>
+          <property>
+            <name>prettier</name>
+            <value>2.0.5</value>
+          </property>
+          <property>
+            <name>@prettier/plugin-php</name> <!-- this could not be written in the simpler to write 'devDependencies' element. -->
+            <value>0.14.2</value>
+          </property>
+        </devDependencyProperties>
         <!-- Specify config file and/or inline config -->
         <configFile>${basedir}/path/to/configfile</configFile>
         <config>
@@ -315,6 +323,62 @@ Supported config file variants are documented on [prettier.io](https://prettier.
 
 To apply prettier to more kinds of files, just add more formats.
 
+<a name="prettier-plugins"></a>
+### Using plugins for prettier
+
+Since spotless uses the actual npm prettier package behind the scenes, it is possible to use prettier with
+[plugins](https://prettier.io/docs/en/plugins.html#official-plugins) or [community-plugins](https://www.npmjs.com/search?q=prettier-plugin) in order to support even more file types.
+
+```xml
+<configuration>
+  <formats>
+    <!-- prettier with java-plugin -->
+    <format>
+      <includes>
+        <include>src/*/java/**/*.java</include>
+      </includes>
+
+      <prettier>
+        <devDependencies>
+            <prettier>2.0.5</prettier>
+            <prettier-plugin-java>0.8.0</prettier-plugin-java>
+        </devDependencies>
+        <config>
+            <tabWidth>4</tabWidth>
+            <parser>java</parser>
+        </config>
+      </prettier>
+    </format>
+
+    <!-- prettier with php-plugin -->
+    <format>
+      <includes>
+        <include>src/**/*.php</include>
+      </includes>
+
+      <prettier>
+        <!-- use the devDependencyProperties writing style when the property-names are not well-formed such as @prettier/plugin-php -->
+        <devDependencyProperties>
+          <property>
+            <name>prettier</name>
+            <value>2.0.5</value>
+          </property>
+          <property>
+            <name>@prettier/plugin-php</name>
+            <value>0.14.2</value>
+          </property>
+        </devDependencyProperties>
+        <config>
+            <tabWidth>3</tabWidth>
+            <parser>php</parser>
+        </config>
+      </prettier>
+    </format>
+
+  </formats>
+</configuration>
+```
+
 ### Prerequisite: prettier requires a working NodeJS version
 
 Prettier, like tsfmt, is based on NodeJS, so to use it, a working NodeJS installation (especially npm) is required on the host running spotless.
@@ -326,9 +390,7 @@ Spotless will try to auto-discover an npm installation. If that is not working f
   ...
 ```
 
-Spotless uses npm to install necessary packages locally. It runs prettier using [J2V8](https://github.com/eclipsesource/J2V8) internally after that.
-Development for J2V8 for non android envs is stopped (for Windows since J2V8 4.6.0 and Unix 4.8.0), therefore Prettier is limited to <= v1.19.0 as newer versions
-use ES6 feature and that needs a newer J2V8 version.
+Spotless uses npm to install necessary packages and to run the prettier formatter after that.
 
 <a name="format"></a>
 

plugin-maven/src/main/java/com/diffplug/spotless/maven/generic/Prettier.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 DiffPlug
+ * Copyright 2016-2020 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,8 @@
 package com.diffplug.spotless.maven.generic;
 
 import java.io.File;
-import java.util.LinkedHashMap;
-import java.util.Map;
+import java.util.*;
+import java.util.stream.Collectors;
 
 import org.apache.maven.plugins.annotations.Parameter;
 
@@ -29,12 +29,17 @@
 
 public class Prettier implements FormatterStepFactory {
 
+	public static final String ERROR_MESSAGE_ONLY_ONE_CONFIG = "must specify exactly one prettierVersion, devDependencies or devDependencyProperties";
+
 	@Parameter
 	private String prettierVersion;
 
 	@Parameter
 	private Map<String, String> devDependencies;
 
+	@Parameter
+	private Properties devDependencyProperties;
+
 	@Parameter
 	private Map<String, String> config;
 
@@ -48,17 +53,17 @@ public class Prettier implements FormatterStepFactory {
 	public FormatterStep newFormatterStep(FormatterStepConfig stepConfig) {
 
 		// check if config is only setup in one way
-		if (this.prettierVersion != null && this.devDependencies != null) {
+		if (moreThanOneNonNull(this.prettierVersion, this.devDependencies, this.devDependencyProperties)) {
 			throw onlyOneConfig();
 		}
-
-		// set dev dependencies
 		if (devDependencies == null) {
-			if (prettierVersion == null || prettierVersion.isEmpty()) {
-				devDependencies = PrettierFormatterStep.defaultDevDependencies();
-			} else {
-				devDependencies = PrettierFormatterStep.defaultDevDependenciesWithPrettier(prettierVersion);
-			}
+			devDependencies = PrettierFormatterStep.defaultDevDependencies(); // fallback
+		}
+
+		if (prettierVersion != null && !prettierVersion.isEmpty()) {
+			this.devDependencies = PrettierFormatterStep.defaultDevDependenciesWithPrettier(prettierVersion);
+		} else if (devDependencyProperties != null) {
+			this.devDependencies = dependencyPropertiesAsMap();
 		}
 
 		File npm = npmExecutable != null ? stepConfig.getFileLocator().locateFile(npmExecutable) : null;
@@ -73,19 +78,20 @@ public FormatterStep newFormatterStep(FormatterStepConfig stepConfig) {
 
 		Map<String, Object> configInline;
 		if (config != null) {
-			configInline = new LinkedHashMap<>();
-			// try to parse string values as integers or booleans
-			for (Map.Entry<String, String> e : config.entrySet()) {
-				try {
-					configInline.put(e.getKey(), Integer.parseInt(e.getValue()));
-				} catch (NumberFormatException ignore) {
-					try {
-						configInline.put(e.getKey(), Boolean.parseBoolean(e.getValue()));
-					} catch (IllegalArgumentException ignore2) {
-						configInline.put(e.getKey(), e.getValue());
-					}
-				}
-			}
+			configInline = config.entrySet().stream()
+					.map(entry -> {
+						try {
+							Integer value = Integer.parseInt(entry.getValue());
+							return new AbstractMap.SimpleEntry<>(entry.getKey(), value);
+						} catch (NumberFormatException ignore) {
+							// ignored
+						}
+						if (Boolean.TRUE.toString().equalsIgnoreCase(entry.getValue()) || Boolean.FALSE.toString().equalsIgnoreCase(entry.getValue())) {
+							return new AbstractMap.SimpleEntry<>(entry.getKey(), Boolean.parseBoolean(entry.getValue()));
+						}
+						return entry;
+					})
+					.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (a, b) -> a, LinkedHashMap::new));
 		} else {
 			configInline = null;
 		}
@@ -96,7 +102,21 @@ public FormatterStep newFormatterStep(FormatterStepConfig stepConfig) {
 		return PrettierFormatterStep.create(devDependencies, stepConfig.getProvisioner(), buildDir, npm, prettierConfig);
 	}
 
+	private boolean moreThanOneNonNull(Object... objects) {
+		return Arrays.stream(objects)
+				.filter(Objects::nonNull)
+				.filter(o -> !(o instanceof String) || !((String) o).isEmpty()) // if it is a string, it should not be empty
+				.count() > 1;
+	}
+
+	private Map<String, String> dependencyPropertiesAsMap() {
+		return this.devDependencyProperties.stringPropertyNames()
+				.stream()
+				.map(name -> new AbstractMap.SimpleEntry<>(name, this.devDependencyProperties.getProperty(name)))
+				.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+	}
+
 	private static IllegalArgumentException onlyOneConfig() {
-		return new IllegalArgumentException("must specify exactly one configFile or config");
+		return new IllegalArgumentException(ERROR_MESSAGE_ONLY_ONE_CONFIG);
 	}
 }

plugin-maven/src/test/java/com/diffplug/spotless/maven/prettier/PrettierFormatStepTest.java

@@ -19,6 +19,7 @@
 
 import java.io.IOException;
 
+import com.diffplug.spotless.maven.generic.Prettier;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
 
@@ -93,6 +94,32 @@ public void unique_dependency_config() throws Exception {
 				"</prettier>");
 
 		MavenRunner.Result result = mavenRunner().withArguments("spotless:apply").runHasError();
-		assertThat(result.output()).contains("must specify exactly one configFile or config");
+		assertThat(result.output()).contains(Prettier.ERROR_MESSAGE_ONLY_ONE_CONFIG);
+	}
+
+	@Test
+	public void custom_plugin() throws Exception {
+		writePomWithFormatSteps(
+				"<includes><include>php-example.php</include></includes>",
+				"<prettier>",
+				"  <devDependencyProperties>",
+				"    <property>",
+				"      <name>prettier</name>",
+				"      <value>2.0.5</value>",
+				"    </property>",
+				"    <property>",
+				"      <name>@prettier/plugin-php</name>",
+				"      <value>0.14.2</value>",
+				"    </property>",
+				"  </devDependencyProperties>",
+				"  <config>",
+				"    <tabWidth>3</tabWidth>",
+				"    <parser>php</parser>",
+				"  </config>",
+				"</prettier>");
+
+		setFile("php-example.php").toResource("npm/prettier/plugins/php.dirty");
+		mavenRunner().withArguments("spotless:apply").runNoError();
+		assertFile("php-example.php").sameAsResource("npm/prettier/plugins/php.clean");
 	}
 }