New feature flag: com.palantir.baseline-format.palantir-java-format=t…

…rue (#936)

Users can opt-in to format their files using our fork of google-java-format (palantir-java-format)

README.md

@@ -319,17 +319,16 @@ spotless {
         importOrder ''
         trimTrailingWhitespace
         indentWithSpaces 4
-
-        // only enabled if you run `./gradlew format -Pcom.palantir.baseline-format.eclipse`
-        eclipse().configFile "$rootDir/.baseline/eclipse.xml"
     }
 }
 ```
 
-We chose the Eclipse formatter because it can be run from the command line and from both IDEs (IntelliJ using the [Eclipse Code Formatter](https://plugins.jetbrains.com/plugin/6546-eclipse-code-formatter) plugin).
+**Add `com.palantir.baseline-format.eclipse=true`** to your gradle.properties to format entire files with the Eclipse formatter. The Eclipse formatter can be run from IntelliJ using the [Eclipse Code Formatter](https://plugins.jetbrains.com/plugin/6546-eclipse-code-formatter) plugin.
 
 To iterate on the eclipse.xml formatter config, you can import it into an instance of Eclipse, edit it through the preferences UI and then export it, or you can manually tune individual values by referring to the master list of [DefaultCodeFormatterConstants](https://github.com/eclipse/eclipse.jdt.core/blob/6a8cee1126829229d648db4ae0e5a6b70a5d4f13/org.eclipse.jdt.core/formatter/org/eclipse/jdt/core/formatter/DefaultCodeFormatterConstants.java) and [DefaultCodeFormatterOptions](https://github.com/eclipse/eclipse.jdt.core/blob/6a8cee1126829229d648db4ae0e5a6b70a5d4f13/org.eclipse.jdt.core/formatter/org/eclipse/jdt/internal/formatter/DefaultCodeFormatterOptions.java#L41-L95). Running `./gradlew :gradle-baseline-java:test -Drecreate=true` should update all the checked-in snapshot test cases.
 
+**Add `com.palantir.baseline-format.palantir-java-format=true`** to your gradle.properties to run our experimental fork of google-java-format. The Palantir Java Formatter can be run from IntelliJ using the [palantir-java-format](https://plugins.jetbrains.com/plugin/13180-palantir-java-format) plugin.
+
 ## com.palantir.baseline-reproducibility
 
 This plugin is a shorthand for the following snippet, which opts-in to reproducible behaviour for all Gradle's Jar, Tar and Zip tasks. (Surprisingly, these tasks are not reproducible by default).

changelog/@unreleased/pr-936.v2.yml

@@ -0,0 +1,6 @@
+type: feature
+feature:
+  description: Users can opt-in to format their files using our fork of google-java-format
+    (palantir-java-format)
+  links:
+  - https://github.com/palantir/gradle-baseline/pull/936

gradle-baseline-java/build.gradle

@@ -15,6 +15,8 @@ dependencies {
     compile 'net.ltgt.gradle:gradle-errorprone-plugin'
     compile 'org.apache.maven.shared:maven-dependency-analyzer'
     compile 'org.github.ngbinh.scalastyle:gradle-scalastyle-plugin_2.11'
+    implementation 'com.palantir.javaformat:palantir-java-format'
+    implementation 'com.palantir.javaformat:gradle-palantir-java-format'
 
     testCompile gradleTestKit()
     testCompile 'com.github.stefanbirkner:system-rules'

gradle-baseline-java/src/main/groovy/com/palantir/baseline/plugins/Baseline.java

@@ -36,6 +36,11 @@ public void apply(Project project) {
 
         rootProject.getPluginManager().apply(BaselineConfig.class);
         rootProject.getPluginManager().apply(BaselineCircleCi.class);
+        if (BaselineFormat.palantirJavaFormatterEnabled(project)) {
+            // This plugin currently sets up IntelliJ but could set up eclipse too in the future, so it doesn't
+            // belong in BaselineIdea.
+            rootProject.getPluginManager().apply("com.palantir.java-format");
+        }
         rootProject.allprojects(proj -> {
             proj.getPluginManager().apply(BaselineCheckstyle.class);
             proj.getPluginManager().apply(BaselineScalastyle.class);

gradle-baseline-java/src/main/groovy/com/palantir/baseline/plugins/BaselineFormat.java

@@ -17,9 +17,20 @@
 package com.palantir.baseline.plugins;
 
 import com.diffplug.gradle.spotless.SpotlessExtension;
+import com.diffplug.spotless.FormatterFunc;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Range;
+import com.palantir.javaformat.java.FormatterService;
+import com.palantir.javaformat.java.JavaFormatterOptions;
+import com.palantir.javaformat.java.JavaFormatterOptions.Style;
+import com.palantir.javaformat.java.JavaOutput;
+import com.palantir.javaformat.java.Replacement;
 import java.io.File;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.ServiceLoader;
+import org.gradle.api.GradleException;
 import org.gradle.api.Project;
 import org.gradle.api.Task;
 import org.gradle.api.file.ConfigurableFileCollection;
@@ -32,6 +43,7 @@ class BaselineFormat extends AbstractBaselinePlugin {
 
     // TODO(dfox): remove this feature flag when we've refined the eclipse.xml sufficiently
     private static final String ECLIPSE_FORMATTING = "com.palantir.baseline-format.eclipse";
+    private static final String PJF_PROPERTY = "com.palantir.baseline-format.palantir-java-format";
     private static final String GENERATED_MARKER = File.separator + "generated";
 
     @Override
@@ -58,10 +70,20 @@ public void apply(Project project) {
                 // use empty string to specify one group for all non-static imports
                 java.importOrder("");
 
+                if (eclipseFormattingEnabled(project) && palantirJavaFormatterEnabled(project)) {
+                    throw new GradleException(
+                            "Can't use both eclipse and palantir-java-format at the same time, please delete one of "
+                                    + ECLIPSE_FORMATTING + " or " + PJF_PROPERTY + " from your gradle.properties");
+                }
+
                 if (eclipseFormattingEnabled(project)) {
                     java.eclipse().configFile(project.file(eclipseXml.toString()));
                 }
 
+                if (palantirJavaFormatterEnabled(project)) {
+                    java.customLazy("palantir-java-format", PalantirJavaFormatterFunc::new);
+                }
+
                 java.trimTrailingWhitespace();
             });
 
@@ -95,7 +117,25 @@ static boolean eclipseFormattingEnabled(Project project) {
         return project.hasProperty(ECLIPSE_FORMATTING);
     }
 
+    static boolean palantirJavaFormatterEnabled(Project project) {
+        return project.hasProperty(PJF_PROPERTY);
+    }
+
     static Path eclipseConfigFile(Project project) {
         return project.getRootDir().toPath().resolve(".baseline/spotless/eclipse.xml");
     }
+
+    private static class PalantirJavaFormatterFunc implements FormatterFunc {
+        private static final JavaFormatterOptions OPTIONS =
+                JavaFormatterOptions.builder().style(Style.PALANTIR).build();
+        private final FormatterService formatterService =
+                Iterables.getOnlyElement(ServiceLoader.load(FormatterService.class));
+
+        @Override
+        public String apply(String input) throws Exception {
+            ImmutableList<Replacement> replacements = formatterService.getFormatReplacements(
+                    OPTIONS, input, ImmutableList.of(Range.closedOpen(0, input.length())));
+            return JavaOutput.applyReplacements(input, replacements);
+        }
+    }
 }

gradle-baseline-java/src/test/groovy/com/palantir/baseline/BaselineFormatIntegrationTest.groovy

@@ -109,6 +109,30 @@ class BaselineFormatIntegrationTest extends AbstractPluginTest {
         assertThatFilesAreTheSame(testedDir, expectedDir)
     }
 
+    def 'palantir java format works'() {
+        def inputDir = new File("src/test/resources/com/palantir/baseline/formatter-in")
+        def expectedDir = new File("src/test/resources/com/palantir/baseline/palantirjavaformat-expected")
+
+        def testedDir = new File(projectDir, "src/main/java")
+        FileUtils.copyDirectory(inputDir, testedDir)
+
+        buildFile << """
+            plugins {
+                id 'java'
+                id 'com.palantir.baseline-format'
+            }
+        """.stripIndent()
+        file('gradle.properties') << "com.palantir.baseline-format.palantir-java-format=true\n"
+
+        when:
+        BuildResult result = with(':format').build()
+
+        then:
+        result.task(":format").outcome == TaskOutcome.SUCCESS
+        result.task(":spotlessApply").outcome == TaskOutcome.SUCCESS
+        assertThatFilesAreTheSame(testedDir, expectedDir)
+    }
+
     def 'eclipse formatter googlejavaformat test cases'() {
         def excludedFiles = [
                 "B19996259.java", // this causes an OOM
@@ -147,7 +171,7 @@ class BaselineFormatIntegrationTest extends AbstractPluginTest {
             def path = file.toPath()
             Path relativized = outputDir.toPath().relativize(path)
             Path expectedFile = expectedDir.toPath().resolve(relativized)
-            if (Boolean.valueOf(System.getProperty("recreate", "false"))) {
+            if (Boolean.getBoolean("recreate")) {
                 Files.createDirectories(expectedFile.getParent())
                 Files.deleteIfExists(expectedFile)
                 Files.copy(path, expectedFile)

gradle-baseline-java/src/test/resources/com/palantir/baseline/palantirjavaformat-expected/BlankLines.java

@@ -0,0 +1,18 @@
+package test;
+
+public class Test {
+    /**
+     * Docstring that looks like a list:
+     *
+     * <p>1. hey 2. there
+     *
+     * <p>with blank line.
+     */
+    Void test() {
+        /*
+        Normal comment
+
+        with blank line.
+        */
+    }
+}

gradle-baseline-java/src/test/resources/com/palantir/baseline/palantirjavaformat-expected/Correct.java

@@ -0,0 +1,11 @@
+package test;
+
+public class Test {
+    void test() {
+        int x = 1;
+        System.out.println("Hello");
+        Optional.of("hello").orElseGet(() -> {
+            return "Hello World";
+        });
+    }
+}

gradle-baseline-java/src/test/resources/com/palantir/baseline/palantirjavaformat-expected/Invalid.java

@@ -0,0 +1,11 @@
+package test;
+
+public class Test {
+    void test() {
+        int x = 1;
+        System.out.println("Hello");
+        Optional.of("hello").orElseGet(() -> {
+            return "Hello World";
+        });
+    }
+}

gradle-baseline-java/src/test/resources/com/palantir/baseline/palantirjavaformat-expected/Multicatch.java

@@ -0,0 +1,15 @@
+package test;
+
+class Multicatch {
+    void test() {
+        try {
+            // whatever
+        } catch (ClassNotFoundException
+                | ClassCastException
+                | NoSuchMethodException
+                | IllegalAccessException
+                | InvocationTargetException e) {
+            // ignore
+        }
+    }
+}

gradle-baseline-java/src/test/resources/com/palantir/baseline/palantirjavaformat-expected/MultilineStringConstant.java

@@ -0,0 +1,18 @@
+package test;
+
+class MultilineStringConstant {
+
+    // NON-NLS comments are required for i18n, it's important they are kept with their strings.
+    private static final String MULTIPLE_LINE_NON_NLS = "field_0,"
+            + //$NON-NLS-1$
+            "field_1,"
+            + //$NON-NLS-1$
+            "field_2,"
+            + //$NON-NLS-1$
+            "field_3,"
+            + //$NON-NLS-1$
+            "field_4"; //$NON-NLS-1$
+
+    private static final String MULTIPLE_LINE_NO_COMMENT =
+            "field_0," + "field_1," + "field_2," + "field_3," + "field_4";
+}

versions.props

@@ -7,6 +7,7 @@ com.google.errorprone:error_prone_test_helpers = 2.3.3
 com.google.guava:guava = 27.1-jre
 com.netflix.nebula:nebula-dependency-recommender = 9.0.0
 com.palantir.configurationresolver:gradle-configuration-resolver-plugin = 0.4.0
+com.palantir.javaformat:* = 0.2.0
 com.palantir.safe-logging:* = 1.11.0
 org.apache.maven.shared:maven-dependency-analyzer = 1.11.1
 org.github.ngbinh.scalastyle:gradle-scalastyle-plugin_2.11 = 1.0.1
@@ -30,3 +31,4 @@ com.palantir.tokens:auth-tokens = 3.6.1
 # dependency-upgrader:OFF
 # Updating to 0.8 would raise our minimum compatible version to 5.2
 net.ltgt.gradle:gradle-errorprone-plugin = 0.7.1
+