Detekt: Add baseline feature and rewrite the internals.

.editorconfig

@@ -0,0 +1,2 @@
+[*.{kt,kts}]
+indent_size=2

build.gradle

@@ -1,5 +1,5 @@
 buildscript {
-  ext.kotlinVersion = '1.2.41'
+  ext.kotlinVersion = '1.2.50'
 
   repositories {
     mavenCentral()
@@ -8,8 +8,10 @@ buildscript {
   }
 
   dependencies {
+    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
     classpath 'com.gradle.publish:plugin-publish-plugin:0.9.10'
-    classpath 'com.github.ben-manes:gradle-versions-plugin:0.17.0'
+    classpath 'com.github.ben-manes:gradle-versions-plugin:0.19.0'
+    classpath 'com.vanniktech:gradle-code-quality-tools-plugin:0.10.0'
     classpath 'com.vanniktech:gradle-android-junit-jacoco-plugin:0.11.0'
     classpath 'com.vanniktech:gradle-maven-publish-plugin:0.2.0'
   }
@@ -18,11 +20,43 @@ buildscript {
 apply plugin: 'groovy'
 apply plugin: 'java-library'
 apply plugin: 'java-gradle-plugin'
+apply plugin: 'kotlin'
 apply plugin: 'com.github.ben-manes.versions'
-apply plugin: 'com.gradle.plugin-publish'
+apply plugin: 'com.vanniktech.code.quality.tools'
 apply plugin: 'com.vanniktech.android.junit.jacoco'
+apply plugin: 'com.gradle.plugin-publish'
 apply plugin: "com.vanniktech.maven.publish"
 
+// Workaround for having both Groovy + Kotlin.
+compileGroovy {
+  dependsOn tasks.getByPath('compileKotlin')
+  classpath += files(compileKotlin.destinationDir)
+}
+
+codeQualityTools {
+  ktlint {
+    toolVersion = '0.23.1'
+  }
+  detekt {
+    toolVersion = '1.0.0.RC7'
+  }
+  findbugs {
+    enabled = false
+  }
+  pmd {
+    enabled = false
+  }
+  checkstyle {
+    enabled = false
+  }
+  cpd {
+    enabled = false
+  }
+  errorProne {
+    enabled = false
+  }
+}
+
 gradlePlugin {
   plugins {
     codeQualityToolsPlugin {
@@ -38,6 +72,16 @@ repositories {
   gradlePluginPortal()
 }
 
+configurations {
+  fixtureClasspath
+}
+
+// Append any extra dependencies to the test fixtures via a custom configuration classpath. This
+// allows us to apply additional plugins in a fixture while still leveraging dependency resolution
+// and de-duplication semantics.
+def metadata = tasks.getByName('pluginUnderTestMetadata')
+metadata.setPluginClasspath(metadata.getPluginClasspath() + configurations.fixtureClasspath)
+
 dependencies {
   api gradleApi()
   api localGroovy()
@@ -48,7 +92,10 @@ dependencies {
 
   testImplementation 'com.android.tools.build:gradle:3.1.2'
   testImplementation 'junit:junit:4.12'
+  testImplementation 'org.assertj:assertj-core:3.10.0'
   testImplementation "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
+
+  fixtureClasspath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
 }
 
 sourceCompatibility = JavaVersion.VERSION_1_7
@@ -67,7 +114,7 @@ pluginBundle {
   }
 }
 
-task wrapper(type: Wrapper) {
+wrapper {
   gradleVersion = '4.8'
   distributionType = Wrapper.DistributionType.ALL
 }

code_quality_tools/detekt.yml

@@ -0,0 +1,19 @@
+failFast: true
+
+potential-bugs:
+  UnsafeCast:
+    active: false # We know what we're doing.
+  LateinitUsage:
+    active: false # We know what we're doing.
+
+style:
+  TopLevelPropertyNaming:
+    active: false
+  MaxLineLength:
+    active: false
+
+comments:
+  UndocumentedPublicClass:
+    active: false
+  UndocumentedPublicFunction:
+    active: false

src/main/groovy/com/vanniktech/code/quality/tools/CodeQualityToolsPlugin.groovy

@@ -18,7 +18,7 @@ class CodeQualityToolsPlugin implements Plugin<Project> {
     rootProject.codeQualityTools.extensions.create('pmd', CodeQualityToolsPluginExtension.Pmd)
     rootProject.codeQualityTools.extensions.create('lint', CodeQualityToolsPluginExtension.Lint)
     rootProject.codeQualityTools.extensions.create('ktlint', CodeQualityToolsPluginExtension.Ktlint)
-    rootProject.codeQualityTools.extensions.create('detekt', CodeQualityToolsPluginExtension.Detekt)
+    rootProject.codeQualityTools.extensions.create('detekt', DetektExtension)
     rootProject.codeQualityTools.extensions.create('cpd', CodeQualityToolsPluginExtension.Cpd)
     rootProject.codeQualityTools.extensions.create('errorProne', CodeQualityToolsPluginExtension.ErrorProne)
 
@@ -326,33 +326,22 @@ class CodeQualityToolsPlugin implements Plugin<Project> {
     def isDetektSupported = isKotlinProject(project)
 
     if (isNotIgnored && isEnabled && isDetektSupported) {
-      project.configurations {
-        detektCheck
+      def task = project.tasks.create("detektCheck", DetektCheckTask)
+      task.version = extension.detekt.toolVersion
+      task.group = GROUP_VERIFICATION
+      task.description = "Runs detekt."
+      task.outputDirectory = new File(project.buildDir, "reports/detekt/")
+      task.configFile = rootProject.file(extension.detekt.config)
+      task.inputs.files(project.fileTree(dir: ".", include: "**/*.kt"))
+
+      task.inputs.property("baseline-file-exists", false)
+
+      if (extension.detekt.baselineFileName != null) {
+        def file = project.file(extension.detekt.baselineFileName)
+        task.baselineFilePath = file.toString()
+        task.inputs.property("baseline-file-exists", file.exists())
       }
 
-      project.dependencies {
-        detektCheck "io.gitlab.arturbosch.detekt:detekt-cli:${extension.detekt.toolVersion}"
-      }
-
-      def output = new File(project.buildDir, "reports/detekt/")
-
-      project.task('detektCheck', type: JavaExec) {
-        def configFile = rootProject.file(extension.detekt.config)
-        inputs.files(project.fileTree(dir: "src", include: "**/*.kt"), configFile)
-        outputs.dir(output.toString())
-        group = GROUP_VERIFICATION
-        description = 'Runs detekt.'
-        main = 'io.gitlab.arturbosch.detekt.cli.Main'
-        classpath = project.configurations.detektCheck
-        args = [
-            "--config", configFile,
-            "--input", project.file("."),
-            "--output", output
-        ]
-      }
-
-      project.check.dependsOn 'detektCheck'
-
       return true
     }
 

src/main/groovy/com/vanniktech/code/quality/tools/CodeQualityToolsPluginExtension.groovy

@@ -203,20 +203,6 @@ class CodeQualityToolsPluginExtension {
     String toolVersion = '0.14.0'
   }
 
-  static class Detekt {
-    /**
-     * ability to enable or disable only detekt for every subproject that is not ignored
-     * @since 0.6.0
-     */
-    boolean enabled = true
-
-    /** @since 0.6.0 */
-    String toolVersion = '1.0.0.RC6'
-
-    /** @since 0.6.0 */
-    String config = 'code_quality_tools/detekt.yml'
-  }
-
   static class Cpd {
     /**
      * ability to enable or disable only cpd for every subproject that is not ignored

src/main/kotlin/com/vanniktech/code/quality/tools/DetektCheckTask.kt

@@ -0,0 +1,59 @@
+package com.vanniktech.code.quality.tools
+
+import org.gradle.api.DefaultTask
+import org.gradle.api.GradleException
+import org.gradle.api.file.FileCollection
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.InputFile
+import org.gradle.api.tasks.Optional
+import org.gradle.api.tasks.OutputDirectory
+import org.gradle.api.tasks.TaskAction
+import org.gradle.api.tasks.TaskExecutionException
+import java.io.File
+
+open class DetektCheckTask : DefaultTask() {
+  @Input lateinit var version: String
+
+  // Ideally this would be an optional input file - https://github.com/gradle/gradle/issues/2016
+  @Input @Optional var baselineFilePath: String? = null
+  @InputFile lateinit var configFile: File
+
+  @OutputDirectory lateinit var outputDirectory: File
+
+  @TaskAction fun run() {
+    val configuration = project.configurations.create("detekt")
+
+    project.dependencies.add("detekt", "io.gitlab.arturbosch.detekt:detekt-cli:$version")
+
+    baselineFilePath?.let { file ->
+      if (!File(file).exists()) {
+        executeDetekt(configuration, shouldCreateBaseLine = true)
+        throw TaskExecutionException(this, GradleException("Aborting build since new baseline file was created"))
+      }
+    }
+
+    executeDetekt(configuration)
+
+    project.tasks.getByName("check").dependsOn("detektCheck")
+  }
+
+  private fun executeDetekt(configuration: FileCollection, shouldCreateBaseLine: Boolean = false) {
+    project.javaexec { task ->
+      task.main = "io.gitlab.arturbosch.detekt.cli.Main"
+      task.classpath = configuration
+      task.args(
+          "--config", configFile,
+          "--input", project.file("."),
+          "--output", outputDirectory
+      )
+
+      if (shouldCreateBaseLine) {
+        task.args("--create-baseline")
+      }
+
+      baselineFilePath?.let {
+        task.args("--baseline", it)
+      }
+    }
+  }
+}

src/main/kotlin/com/vanniktech/code/quality/tools/DetektExtension.kt

@@ -0,0 +1,24 @@
+package com.vanniktech.code.quality.tools
+
+open class DetektExtension {
+  /**
+   * Ability to enable or disable only detekt for every subproject that is not ignored.
+   * @since 0.6.0
+   */
+  var enabled: Boolean = true
+
+  /** @since 0.6.0 */
+  var toolVersion: String = "1.0.0.RC6"
+
+  /** @since 0.6.0 */
+  var config: String = "code_quality_tools/detekt.yml"
+
+  /**
+   * Optional baseline file. If one is present it will be used in the detektCheck task.
+   * If this name is specified however the file is not present it will be generated.
+   * This mirrors the baseline mechanism from Android Lint.
+   *
+   * @since 0.11.0
+   */
+  var baselineFileName: String? = null
+}

src/test/groovy/com/vanniktech/code/quality/tools/CodeQualityToolsPluginExtensionForTests.groovy

@@ -7,7 +7,7 @@ package com.vanniktech.code.quality.tools
   CodeQualityToolsPluginExtension.Pmd pmd = new CodeQualityToolsPluginExtension.Pmd()
   CodeQualityToolsPluginExtension.Lint lint = new CodeQualityToolsPluginExtension.Lint()
   CodeQualityToolsPluginExtension.Ktlint ktlint = new CodeQualityToolsPluginExtension.Ktlint()
-  CodeQualityToolsPluginExtension.Detekt detekt = new CodeQualityToolsPluginExtension.Detekt()
+  DetektExtension detekt = new DetektExtension()
   CodeQualityToolsPluginExtension.Cpd cpd = new CodeQualityToolsPluginExtension.Cpd()
   CodeQualityToolsPluginExtension.ErrorProne errorProne = new CodeQualityToolsPluginExtension.ErrorProne()
 }