License derived from .baseline/copyright

README.md

@@ -224,9 +224,10 @@ as that file will be overridden on updates.
 
 ### Copyright Checks
 
-By default Baseline enforces Palantir copyright at the beginning of files. To change this, edit the template copyright
-in `.baseline/copyright/*.txt` and the RegexpHeader checkstyle configuration in `.baseline/checkstyle/checkstyle.xml`
+Baseline enforces Palantir copyright at the beginning of files when applying `com.palantir.baseline-format`. To change this, edit the template copyrights
+in `.baseline/copyright/*.txt`. The largest file (sorted lexicographically) will be used to generate a new copyright if one is missing, or none of the existing templates match.￿
 
+To automatically update all files with mismatching/missing copyrights, run `./gradlew format`.
 
 ## com.palantir.baseline-class-uniqueness
 When applied to a java project, this inspects all the jars in your `runtimeClasspath` configuration and records any conflicts to a `baseline-class-uniqueness.lock` file. For example:

changelog/@unreleased/pr-1217.v2.yml

@@ -0,0 +1,6 @@
+type: improvement
+improvement:
+  description: Enforcing copyright based on the first file (lexicographically) founds
+    in `.baseline/copyright`.
+  links:
+  - https://github.com/palantir/gradle-baseline/pull/1217

gradle-baseline-java-config/resources/checkstyle/checkstyle.xml

@@ -18,10 +18,6 @@
     <module name="NewlineAtEndOfFile"> <!-- Java Style Guide: Line ending: LF -->
         <property name="lineSeparator" value="lf"/>
     </module>
-    <module name="RegexpHeader">
-        <property name="header" value="^/\*$\n^ \* \(c\) Copyright \d{4} Palantir Technologies Inc\. All rights reserved\.$"/>
-        <property name="fileExtensions" value=".java,.ts"/>
-    </module>
     <module name="RegexpMultiline"> <!-- Development Practices: Writing good unit tests -->
         <property name="fileExtensions" value="java"/>
         <property name="format" value="@VisibleForTesting\s+(protected|public)"/>

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

@@ -17,9 +17,19 @@
 package com.palantir.baseline.plugins;
 
 import com.diffplug.gradle.spotless.SpotlessExtension;
+import com.diffplug.spotless.FormatterStep;
+import com.google.common.base.Splitter;
+import com.google.common.collect.Streams;
 import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.Comparator;
+import java.util.List;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 import org.gradle.api.GradleException;
 import org.gradle.api.Project;
 import org.gradle.api.Task;
@@ -41,6 +51,109 @@ class BaselineFormat extends AbstractBaselinePlugin {
     public void apply(Project project) {
         this.project = project;
 
+        project.getPluginManager().apply("com.diffplug.gradle.spotless");
+
+        SpotlessExtension spotlessExtension = project.getExtensions().getByType(SpotlessExtension.class);
+        // Keep spotless from eagerly configuring all other tasks.  We do the same thing as the enforceCheck
+        // property below by making the check task depend on spotlessCheck.
+        // See  https://github.com/diffplug/spotless/issues/444
+        spotlessExtension.setEnforceCheck(false);
+
+        // Allow disabling copyright for tests
+        if (!"false".equals(project.findProperty("com.palantir.baseline-format.copyright"))) {
+            configureCopyrightStep(project, spotlessExtension);
+        }
+
+        // necessary because SpotlessPlugin creates tasks in an afterEvaluate block
+        TaskProvider<Task> formatTask = project.getTasks().register("format", task -> {
+            task.setGroup("Formatting");
+        });
+        project.afterEvaluate(p -> {
+            formatTask.configure(t -> {
+                t.dependsOn("spotlessApply");
+            });
+
+            // re-enable spotless checking, but lazily so it doesn't eagerly configure everything else
+            project.getTasks().named(JavaBasePlugin.CHECK_TASK_NAME).configure(t -> {
+                t.dependsOn(project.getTasks().named("spotlessCheck"));
+            });
+
+            // The copyright step configures itself lazily to allow for baselineUpdateConfig to potentially create the
+            // right files. Therefore, also make sure that these will run in the right order.
+            project.getPluginManager().withPlugin("com.palantir.baseline-config", baselineConfig -> {
+                project.getTasks()
+                        .matching(t -> t.getName().startsWith("spotless"))
+                        .configureEach(t -> t.mustRunAfter("baselineUpdateConfig"));
+            });
+        });
+
+        project.getPluginManager().withPlugin("java", plugin -> {
+            configureSpotlessJava(project, spotlessExtension);
+        });
+    }
+
+    /**
+     * Necessary in order to not fail right away if the copyright folder doesn't exist yet, because it would be created
+     * by {@code baselineUpdateConfig}.
+     */
+    private FormatterStep createLazyLicenseHeaderStep(Project project) {
+        // Spotless will consider the license header to be the file prefix up to the first line starting with delimiter
+        String delimiter = "(?! \\*|/\\*| \\*/)";
+
+        return new LazyFormatterStep(MultiLicenseHeaderStep.name(), () -> {
+            List<String> headers = computeCopyrightHeaders(project);
+            return MultiLicenseHeaderStep.createFromHeaders(headers, delimiter);
+        });
+    }
+
+    private void configureCopyrightStep(Project project, SpotlessExtension spotlessExtension) {
+        project.getPluginManager().withPlugin("java", javaPlugin -> {
+            spotlessExtension.java(java -> java.addStep(createLazyLicenseHeaderStep(project)));
+        });
+
+        // This is tricky as configuring this naively yields the following error:
+        // > You must apply the groovy plugin before the spotless plugin if you are using the groovy extension.
+        project.getPluginManager().withPlugin("groovy", groovyPlugin -> {
+            spotlessExtension.groovy(groovy -> groovy.addStep(createLazyLicenseHeaderStep(project)));
+        });
+    }
+
+    /**
+     * Computes all the copyright headers based on the files inside baseline's {@code copyright} directory. This list
+     * is sorted lexicographically by the file names.
+     */
+    private List<String> computeCopyrightHeaders(Project project) {
+        File copyrightDir = project.getRootProject().file(getConfigDir() + "/copyright");
+        Stream<Path> files;
+        try {
+            files = Files.list(copyrightDir.toPath()).sorted(Comparator.comparing(Path::getFileName));
+        } catch (IOException e) {
+            throw new RuntimeException("Couldn't list copyright directory: " + copyrightDir);
+        }
+
+        return files.map(BaselineFormat::computeCopyrightComment).collect(Collectors.toList());
+    }
+
+    private static String computeCopyrightComment(Path copyrightFile) {
+        String copyrightContents;
+        try {
+            copyrightContents = new String(Files.readAllBytes(copyrightFile), StandardCharsets.UTF_8);
+        } catch (IOException e) {
+            throw new RuntimeException("Couldn't read copyright file " + copyrightFile, e);
+        }
+        // Spotless expects '$YEAR' but our current patterns use ${today.year}
+        String copyright = copyrightContents
+                .replaceAll(Pattern.quote("${today.year}"), "\\$YEAR")
+                .trim();
+        // Spotless expects the literal header so we have to add the Java comment guard and prefixes
+        return Streams.concat(
+                        Stream.of("/*"),
+                        Streams.stream(Splitter.on('\n').split(copyright)).map(line -> " " + ("* " + line).trim()),
+                        Stream.of(" */"))
+                .collect(Collectors.joining("\n"));
+    }
+
+    private static void configureSpotlessJava(Project project, SpotlessExtension spotlessExtension) {
         if (palantirJavaFormatterState(project) == FormatterState.ON) {
             project.getPlugins().apply(PJF_PLUGIN); // provides the formatDiff task
         }
@@ -56,58 +169,35 @@ public void apply(Project project) {
             });
         }
 
-        project.getPluginManager().withPlugin("java", plugin -> {
-            project.getPluginManager().apply("com.diffplug.gradle.spotless");
-            Path eclipseXml = eclipseConfigFile(project);
-
-            SpotlessExtension spotlessExtension = project.getExtensions().getByType(SpotlessExtension.class);
-            spotlessExtension.java(java -> {
-                // Configure a lazy FileCollection then pass it as the target
-                ConfigurableFileCollection allJavaFiles = project.files();
-                project.getConvention()
-                        .getPlugin(JavaPluginConvention.class)
-                        .getSourceSets()
-                        .all(sourceSet -> allJavaFiles.from(
-                                sourceSet.getAllJava().filter(file ->
-                                        !file.toString().contains(GENERATED_MARKER))));
-
-                java.target(allJavaFiles);
-                java.removeUnusedImports();
-                // use empty string to specify one group for all non-static imports
-                java.importOrder("");
-
-                if (eclipseFormattingEnabled(project)) {
-                    java.eclipse().configFile(project.file(eclipseXml.toString()));
-                }
-
-                java.trimTrailingWhitespace();
-            });
+        Path eclipseXml = eclipseConfigFile(project);
+        spotlessExtension.java(java -> {
+            // Configure a lazy FileCollection then pass it as the target
+            ConfigurableFileCollection allJavaFiles = project.files();
+            project.getConvention()
+                    .getPlugin(JavaPluginConvention.class)
+                    .getSourceSets()
+                    .all(sourceSet -> allJavaFiles.from(sourceSet.getAllJava().filter(file ->
+                            !file.toString().contains(GENERATED_MARKER))));
+
+            java.target(allJavaFiles);
+            java.removeUnusedImports();
+            // use empty string to specify one group for all non-static imports
+            java.importOrder("");
+
+            if (eclipseFormattingEnabled(project)) {
+                java.eclipse().configFile(project.file(eclipseXml.toString()));
+            }
+
+            java.trimTrailingWhitespace();
+        });
 
-            // Keep spotless from eagerly configuring all other tasks.  We do the same thing as the enforceCheck
-            // property below by making the check task depend on spotlessCheck.
-            // See  https://github.com/diffplug/spotless/issues/444
-            spotlessExtension.setEnforceCheck(false);
+        project.afterEvaluate(p -> {
+            Task spotlessJava = project.getTasks().getByName("spotlessJava");
+            if (eclipseFormattingEnabled(project) && !Files.exists(eclipseXml)) {
+                spotlessJava.dependsOn(":baselineUpdateConfig");
+            }
 
-            // necessary because SpotlessPlugin creates tasks in an afterEvaluate block
-            TaskProvider<Task> formatTask = project.getTasks().register("format", task -> {
-                task.setGroup("Formatting");
-            });
-            project.afterEvaluate(p -> {
-                Task spotlessJava = project.getTasks().getByName("spotlessJava");
-                Task spotlessApply = project.getTasks().getByName("spotlessApply");
-                if (eclipseFormattingEnabled(project) && !Files.exists(eclipseXml)) {
-                    spotlessJava.dependsOn(":baselineUpdateConfig");
-                }
-                formatTask.configure(t -> {
-                    t.dependsOn(spotlessApply);
-                });
-                project.getTasks().withType(JavaCompile.class).configureEach(spotlessJava::mustRunAfter);
-
-                // re-enable spotless checking, but lazily so it doesn't eagerly configure everything else
-                project.getTasks().named(JavaBasePlugin.CHECK_TASK_NAME).configure(t -> {
-                    t.dependsOn(project.getTasks().named("spotlessCheck"));
-                });
-            });
+            project.getTasks().withType(JavaCompile.class).configureEach(spotlessJava::mustRunAfter);
         });
     }
 

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

@@ -0,0 +1,59 @@
+/*
+ * (c) Copyright 2020 Palantir Technologies Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.palantir.baseline.plugins;
+
+import com.diffplug.spotless.FormatterStep;
+import com.google.common.base.Suppliers;
+import java.io.File;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.util.function.Supplier;
+import javax.annotation.Nullable;
+
+/** A lazy {@link FormatterStep} that instantiates its delegate only when methods are called. */
+class LazyFormatterStep implements FormatterStep {
+    private final String name;
+    private transient Supplier<FormatterStep> delegate;
+
+    LazyFormatterStep(String name, Supplier<FormatterStep> delegate) {
+        this.name = name;
+        this.delegate = Suppliers.memoize(delegate::get);
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Nullable
+    @Override
+    public String format(String rawUnix, File file) throws Exception {
+        return delegate.get().format(rawUnix, file);
+    }
+
+    public final void writeObject(ObjectOutputStream output) throws IOException {
+        output.defaultWriteObject();
+        output.writeObject(delegate.get());
+    }
+
+    public void readObject(ObjectInputStream input) throws IOException, ClassNotFoundException {
+        input.defaultReadObject();
+        FormatterStep serialized = (FormatterStep) input.readObject();
+        delegate = () -> serialized;
+    }
+}