Make Gradle task to check if dependencies are sorted cacheable

sort-dependencies-gradle-plugin/src/main/kotlin/com/squareup/sort/BaseSortDependenciesTask.kt

@@ -0,0 +1,30 @@
+package com.squareup.sort
+
+import org.gradle.api.DefaultTask
+import org.gradle.api.file.ConfigurableFileCollection
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.Classpath
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.InputFiles
+import org.gradle.api.tasks.Optional
+import org.gradle.api.tasks.options.Option
+
+abstract class BaseSortDependenciesTask : DefaultTask() {
+
+  @get:Classpath
+  @get:InputFiles
+  abstract val sortProgram: ConfigurableFileCollection
+
+  /** The app version limits what options we can pass it. */
+  @get:Input
+  abstract val version: Property<String>
+
+  @get:Optional
+  @get:Option(option = "verbose", description = "Enables verbose logging.")
+  @get:Input
+  abstract val verbose: Property<Boolean>
+
+  @get:Optional
+  @get:Input
+  abstract val insertBlankLines: Property<Boolean>
+}

sort-dependencies-gradle-plugin/src/main/kotlin/com/squareup/sort/CheckSortDependenciesTask.kt

@@ -0,0 +1,83 @@
+package com.squareup.sort
+
+import com.squareup.sort.internal.VersionNumber
+import org.gradle.api.file.DirectoryProperty
+import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.plugins.JavaBasePlugin
+import org.gradle.api.tasks.*
+import org.gradle.process.ExecOperations
+import java.io.File
+import java.nio.file.Path
+import java.nio.file.Paths
+import javax.inject.Inject
+
+@CacheableTask
+abstract class CheckSortDependenciesTask @Inject constructor(
+  private val execOps: ExecOperations
+) : BaseSortDependenciesTask() {
+
+  init {
+    group = JavaBasePlugin.VERIFICATION_GROUP
+    description = "Checks if the dependencies block in a Gradle build script is sorted"
+  }
+
+  @get:InputFile
+  @get:PathSensitive(PathSensitivity.RELATIVE)
+  abstract val buildScript: RegularFileProperty
+
+  @get:OutputDirectory
+  abstract val outputDirectory: DirectoryProperty
+
+  @TaskAction
+  fun action() {
+    val buildScript = buildScript.get().asFile.absolutePath
+    val verbose = verbose.getOrElse(false)
+
+    logger.info("Checking if '$buildScript' is sorted.")
+
+    val version = VersionNumber.parse(version.get().removeSuffix("-SNAPSHOT"))
+
+    val result = execOps.exec { execSpec ->
+      execSpec.setIgnoreExitValue(true)
+      execSpec.commandLine = listOf(
+        "java",
+        "-cp", sortProgram.asPath,
+        "com.squareup.sort.MainKt",
+        buildScript,
+        "--mode", "check"
+      )
+
+      // Not really intended to be user-specified
+      if (version > VersionNumber.parse("0.8")) {
+        execSpec.args("--context", "gradle")
+      }
+
+      if (verbose) {
+        if (version < VersionNumber.parse("0.3")) {
+          logger.warn("--verbose specified by version < 0.3. Ignoring flag.")
+        } else {
+          execSpec.args("--verbose")
+        }
+      }
+    }
+
+    val resultText = when (result.exitValue) {
+      0 -> "Dependencies are correctly sorted."
+      2 -> "Dependencies are not correctly sorted."
+      3 -> "There were parse errors."
+      else -> "The exit code ${result.exitValue} is not known."
+    }
+
+    outputDirectory.asFile.get().mkdirs()
+    val outputPath : Path = Paths.get(outputDirectory.asFile.get().absolutePath, "result.txt")
+    File(outputPath.toUri()).writeText(resultText)
+
+    if (result.exitValue == 2) {
+      throw VerificationException("Dependencies are not correctly sorted.")
+    } else if (result.exitValue == 3) {
+      throw RuntimeException("There were parse errors.")
+    } else if (result.exitValue > 0) {
+      throw RuntimeException("The command failed with exit code ${result.exitValue}.")
+    }
+  }
+}

sort-dependencies-gradle-plugin/src/main/kotlin/com/squareup/sort/SortDependenciesPlugin.kt

@@ -3,6 +3,7 @@ package com.squareup.sort
 import org.gradle.api.Plugin
 import org.gradle.api.Project
 import org.gradle.api.artifacts.Configuration
+import org.gradle.api.file.ProjectLayout
 import org.gradle.language.base.plugins.LifecycleBasePlugin
 
 @Suppress("unused")
@@ -27,10 +28,10 @@ class SortDependenciesPlugin : Plugin<Project> {
     }
 
     tasks.register("sortDependencies", SortDependenciesTask::class.java) { t ->
-      t.configure("sort", target, sortApp, extension)
+      t.configure(target, sortApp, extension)
     }
-    val checkTask = tasks.register("checkSortDependencies", SortDependenciesTask::class.java) { t ->
-      t.configure("check", target, sortApp, extension)
+    val checkTask = tasks.register("checkSortDependencies", CheckSortDependenciesTask::class.java) { t ->
+      t.configure(target, sortApp, layout, extension)
     }
 
     afterEvaluate {
@@ -46,15 +47,26 @@ class SortDependenciesPlugin : Plugin<Project> {
   }
 
   private fun SortDependenciesTask.configure(
-    mode: String,
     project: Project,
     sortApp: Configuration,
     extension: SortDependenciesExtension,
   ) {
     buildScript.set(project.buildFile)
     sortProgram.setFrom(sortApp)
     version.set(extension.version)
-    this.mode.set(mode)
+    insertBlankLines.set(extension.insertBlankLines)
+  }
+
+  private fun CheckSortDependenciesTask.configure(
+    project: Project,
+    sortApp: Configuration,
+    layout: ProjectLayout,
+    extension: SortDependenciesExtension,
+  ) {
+    buildScript.set(project.buildFile)
+    sortProgram.setFrom(sortApp)
+    version.set(extension.version)
+    outputDirectory.set(layout.buildDirectory.dir("generated/sort-dependencies"))
     insertBlankLines.set(extension.insertBlankLines)
   }
 }

sort-dependencies-gradle-plugin/src/main/kotlin/com/squareup/sort/SortDependenciesTask.kt

@@ -1,25 +1,15 @@
 package com.squareup.sort
 
 import com.squareup.sort.internal.VersionNumber
-import org.gradle.api.DefaultTask
-import org.gradle.api.InvalidUserDataException
-import org.gradle.api.file.ConfigurableFileCollection
 import org.gradle.api.file.RegularFileProperty
 import org.gradle.api.plugins.JavaBasePlugin
-import org.gradle.api.provider.Property
-import org.gradle.api.tasks.Classpath
-import org.gradle.api.tasks.Input
-import org.gradle.api.tasks.InputFiles
-import org.gradle.api.tasks.Internal
-import org.gradle.api.tasks.Optional
-import org.gradle.api.tasks.TaskAction
-import org.gradle.api.tasks.options.Option
+import org.gradle.api.tasks.*
 import org.gradle.process.ExecOperations
 import javax.inject.Inject
 
 abstract class SortDependenciesTask @Inject constructor(
   private val execOps: ExecOperations
-) : DefaultTask() {
+) : BaseSortDependenciesTask() {
 
   init {
     group = JavaBasePlugin.VERIFICATION_GROUP
@@ -34,37 +24,12 @@ abstract class SortDependenciesTask @Inject constructor(
   @get:Internal
   abstract val buildScript: RegularFileProperty
 
-  @get:Classpath
-  @get:InputFiles
-  abstract val sortProgram: ConfigurableFileCollection
-
-  /** The app version limits what options we can pass it. */
-  @get:Input
-  abstract val version: Property<String>
-
-  @get:Input
-  abstract val mode: Property<String>
-
-  @get:Optional
-  @get:Option(option = "verbose", description = "Enables verbose logging.")
-  @get:Input
-  abstract val verbose: Property<Boolean>
-
-  @get:Optional
-  @get:Input
-  abstract val insertBlankLines: Property<Boolean>
-
   @TaskAction fun action() {
     val buildScript = buildScript.get().asFile.absolutePath
-    val mode = mode.getOrElse("sort")
     val verbose = verbose.getOrElse(false)
     val insertBlankLines = insertBlankLines.getOrElse(true)
 
-    if (mode != "check" && mode != "sort") {
-      throw InvalidUserDataException("Mode must be 'sort' or 'check'. Was '$mode'.")
-    }
-
-    logger.info("Sorting '$buildScript' using mode '$mode'.")
+    logger.info("Sorting '$buildScript'.")
 
     val version = VersionNumber.parse(version.get().removeSuffix("-SNAPSHOT"))
 
@@ -74,7 +39,8 @@ abstract class SortDependenciesTask @Inject constructor(
         classpath = sortProgram
         args = buildList {
           add(buildScript)
-          option("--mode", mode)
+          add("--mode")
+          add("sort")
 
           // Not really intended to be user-specified
           if (version > VersionNumber.parse("0.8")) {