Add configuration property to to select the gradle worker isolation strategy

README.md

@@ -43,9 +43,11 @@ Please note that `ktfmt-gradle` relies on `ktfmt` hence the minimum supported JD
 
 Please also note the following requirements:
 
-* **Kotlin 1.4+**. In order to reformat Kotlin 1.4 code, you need run on **Gradle to 6.8+** (This is due to Gradle 6.7 embedding Kotlin 1.3.x - See [#12660](https://github.com/gradle/gradle/issues/12660)).
+* **Kotlin 1.4+**. In order to reformat Kotlin 1.4 code, you need run on **Gradle to 6.8+** (This is due to Gradle 6.7
+  embedding Kotlin 1.3.x - See [#12660](https://github.com/gradle/gradle/issues/12660)).
 
-* **Android**. `ktfmt-gradle` relies on features from **Android Gradle Plugin 4.1+**. So make sure you bump AGP before applying this plugin.
+* **Android**. `ktfmt-gradle` relies on features from **Android Gradle Plugin 4.1+**. So make sure you bump AGP before
+  applying this plugin.
 
 ### Task
 
@@ -91,10 +93,10 @@ To enable different styles you can simply:
 ktfmt {
     // Dropbox style - 4 space indentation
     dropboxStyle()
-    
+
     // Google style - 2 space indentation
     googleStyle()
-    
+
     // KotlinLang style - 4 space indentation - From kotlinlang.org/docs/coding-conventions.html
     kotlinLangStyle()
 }
@@ -115,11 +117,24 @@ ktfmt {
 }
 ```
 
+The Ktfmt formatter can be invoked from gradle with different dependency isolation strategies. By default, there is no
+isolation between ktfmt and other build dependencies. This should be sufficient for most projects. When you encounter
+errors related to dependency conflicts, you can try to invoke ktfmt in a separate process with its own classpath.
+
+```kotlin
+import com.ncorti.ktfmt.gradle.GradleWorkerIsolationStrategy
+
+ktfmt {
+    gradleWorkerIsolationStrategy.set(GradleWorkerIsolationStrategy.NO_ISOLATION)
+}
+```
+
 ## Using with a pre-commit hook 🎣
 
 You can leverage the `--include-only` to let ktfmt-gradle run only on a specific subset of files.
 
-To this you can register a simple task of type `KtfmtCheckTask` or `KtfmtFormatTask` in your `build.gradle.kts` as follows:
+To this you can register a simple task of type `KtfmtCheckTask` or `KtfmtFormatTask` in your `build.gradle.kts` as
+follows:
 
 ```kotlin
 import com.ncorti.ktfmt.gradle.tasks.*

example/build.gradle.kts

@@ -1,3 +1,5 @@
+import com.ncorti.ktfmt.gradle.GradleWorkerIsolationStrategy
+
 plugins {
     kotlin("jvm")
     id("com.ncorti.ktfmt.gradle")
@@ -7,6 +9,7 @@ plugins {
 
 ktfmt {
     kotlinLangStyle()
+    gradleWorkerIsolationStrategy.set(GradleWorkerIsolationStrategy.NO_ISOLATION)
 }
 
 dependencies {

plugin-build/plugin/src/main/java/com/ncorti/ktfmt/gradle/GradleWorkerIsolationStrategy.kt

@@ -0,0 +1,21 @@
+package com.ncorti.ktfmt.gradle
+
+import com.ncorti.ktfmt.gradle.GradleWorkerIsolationStrategy.*
+import org.gradle.api.file.ConfigurableFileCollection
+import org.gradle.workers.WorkQueue
+import org.gradle.workers.WorkerExecutor
+
+enum class GradleWorkerIsolationStrategy {
+    NO_ISOLATION,
+    PROCESS_ISOLATION
+}
+
+fun WorkerExecutor.getWorkQueue(
+    isolationStrategy: GradleWorkerIsolationStrategy,
+    classPath: ConfigurableFileCollection
+): WorkQueue {
+    return when (isolationStrategy) {
+        NO_ISOLATION -> this.noIsolation()
+        PROCESS_ISOLATION -> this.processIsolation { it.classpath.from(classPath) }
+    }
+}

plugin-build/plugin/src/main/java/com/ncorti/ktfmt/gradle/KtfmtExtension.kt

@@ -14,6 +14,7 @@ abstract class KtfmtExtension {
         continuationIndent.convention(DEFAULT_CONTINUATION_INDENT)
         removeUnusedImports.convention(DEFAULT_REMOVE_UNUSED_IMPORTS)
         debuggingPrintOpsAfterFormatting.convention(DEFAULT_DEBUGGING_PRINT_OPTS)
+        gradleWorkerIsolationStrategy.convention(DEFAULT_GRADLE_WORKER_ISOLATION_STRATEGY)
     }
 
     internal var ktfmtStyle = FACEBOOK
@@ -54,6 +55,9 @@ abstract class KtfmtExtension {
      */
     abstract val debuggingPrintOpsAfterFormatting: Property<Boolean>
 
+    /** Defines the isolation strategy between the ktfmt classpath and the project classpath. */
+    abstract val gradleWorkerIsolationStrategy: Property<GradleWorkerIsolationStrategy>
+
     /** Enables --dropbox-style (equivalent to set blockIndent to 4 and continuationIndent to 4). */
     @Suppress("MagicNumber")
     fun dropboxStyle() {
@@ -97,5 +101,7 @@ abstract class KtfmtExtension {
         internal const val DEFAULT_CONTINUATION_INDENT: Int = 4
         internal const val DEFAULT_REMOVE_UNUSED_IMPORTS: Boolean = true
         internal const val DEFAULT_DEBUGGING_PRINT_OPTS: Boolean = false
+        internal val DEFAULT_GRADLE_WORKER_ISOLATION_STRATEGY: GradleWorkerIsolationStrategy =
+            GradleWorkerIsolationStrategy.NO_ISOLATION
     }
 }

plugin-build/plugin/src/main/java/com/ncorti/ktfmt/gradle/KtfmtPlugin.kt

@@ -52,6 +52,7 @@ abstract class KtfmtPlugin : Plugin<Project> {
 
             project.tasks.withType(KtfmtBaseTask::class.java).configureEach {
                 it.ktfmtClasspath.from(ktFmt)
+                it.isolationStrategy.set(ktfmtExtension.gradleWorkerIsolationStrategy)
             }
 
             topLevelFormat = createTopLevelFormatTask(project)

plugin-build/plugin/src/main/java/com/ncorti/ktfmt/gradle/tasks/KtfmtBaseTask.kt

@@ -1,8 +1,6 @@
 package com.ncorti.ktfmt.gradle.tasks
 
-import com.ncorti.ktfmt.gradle.FormattingOptionsBean
-import com.ncorti.ktfmt.gradle.KtfmtExtension
-import com.ncorti.ktfmt.gradle.KtfmtPlugin
+import com.ncorti.ktfmt.gradle.*
 import com.ncorti.ktfmt.gradle.tasks.worker.KtfmtWorkAction
 import com.ncorti.ktfmt.gradle.tasks.worker.Result
 import com.ncorti.ktfmt.gradle.util.d
@@ -56,6 +54,8 @@ internal constructor(
     @get:Input
     abstract val includeOnly: Property<String>
 
+    @get:Input abstract val isolationStrategy: Property<GradleWorkerIsolationStrategy>
+
     @get:PathSensitive(PathSensitivity.RELATIVE)
     @get:InputFiles
     @get:IgnoreEmptyDirectories
@@ -64,8 +64,8 @@ internal constructor(
 
     @TaskAction
     internal fun taskAction() {
-        val workQueue =
-            workerExecutor.classLoaderIsolation { spec -> spec.classpath.from(ktfmtClasspath) }
+        val workQueue = workerExecutor.getWorkQueue(isolationStrategy.get(), ktfmtClasspath)
+
         execute(workQueue)
     }
 

plugin-build/plugin/src/test/java/com/ncorti/ktfmt/gradle/tasks/KtfmtCheckTaskIntegrationTest.kt

@@ -9,6 +9,8 @@ import org.intellij.lang.annotations.Language
 import org.junit.jupiter.api.BeforeEach
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.io.TempDir
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
 
 internal class KtfmtCheckTaskIntegrationTest {
 
@@ -157,6 +159,45 @@ internal class KtfmtCheckTaskIntegrationTest {
         assertThat(result.output).contains("Reusing configuration cache.")
     }
 
+    @ParameterizedTest
+    @ValueSource(ints = [10, 15, 30, 50, 100, 1000])
+    fun `check task can check the formatting of multiple files using with default no-isolation strategy`(
+        n: Int
+    ) {
+        repeat(n) { index ->
+            createTempFile(content = "val answer${index} = 42\n", fileName = "TestFile$index.kt")
+        }
+        val result =
+            GradleRunner.create()
+                .withProjectDir(tempDir)
+                .withPluginClasspath()
+                .withArguments("ktfmtCheckMain", "--info")
+                .forwardOutput()
+                .build()
+
+        assertThat(result.task(":ktfmtCheckMain")?.outcome).isEqualTo(SUCCESS)
+    }
+
+    @ParameterizedTest
+    @ValueSource(ints = [10, 15, 30, 50, 100, 1000])
+    fun `check task can check the formatting of multiple files using process isolation strategy`(
+        n: Int
+    ) {
+        configureProcessIsolationStrategy()
+        repeat(n) { index ->
+            createTempFile(content = "val answer${index} = 42\n", fileName = "TestFile$index.kt")
+        }
+        val result =
+            GradleRunner.create()
+                .withProjectDir(tempDir)
+                .withPluginClasspath()
+                .withArguments("ktfmtCheckMain", "--info")
+                .forwardOutput()
+                .build()
+
+        assertThat(result.task(":ktfmtCheckMain")?.outcome).isEqualTo(SUCCESS)
+    }
+
     @Test
     fun `check task validates all the file with a failure`() {
         createTempFile(content = "val answer = `\n", fileName = "File1.kt")
@@ -196,6 +237,11 @@ internal class KtfmtCheckTaskIntegrationTest {
         assertThat(result.output).contains("Valid formatting for:")
     }
 
+    private fun configureProcessIsolationStrategy() {
+        File("src/test/resources/jvmProjectProcessIsolation")
+            .copyRecursively(tempDir, overwrite = true)
+    }
+
     private fun createTempFile(
         @Language("kotlin") content: String,
         fileName: String = "TestFile.kt",

plugin-build/plugin/src/test/java/com/ncorti/ktfmt/gradle/tasks/KtfmtFormatTaskIntegrationTest.kt

@@ -10,6 +10,8 @@ import org.intellij.lang.annotations.Language
 import org.junit.jupiter.api.BeforeEach
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.io.TempDir
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
 
 internal class KtfmtFormatTaskIntegrationTest {
 
@@ -182,6 +184,43 @@ internal class KtfmtFormatTaskIntegrationTest {
         assertThat(result.output).contains("Reusing configuration cache.")
     }
 
+    @ParameterizedTest
+    @ValueSource(ints = [10, 15, 30, 50, 100, 1000])
+    fun `format task can format multiple files using with default no-isolation workerQueue`(
+        n: Int
+    ) {
+        repeat(n) { index ->
+            createTempFile(content = "val answer${index}=42\n", fileName = "TestFile$index.kt")
+        }
+        val result =
+            GradleRunner.create()
+                .withProjectDir(tempDir)
+                .withPluginClasspath()
+                .withArguments("ktfmtFormatMain", "--info")
+                .forwardOutput()
+                .build()
+
+        assertThat(result.task(":ktfmtFormatMain")?.outcome).isEqualTo(SUCCESS)
+    }
+
+    @ParameterizedTest
+    @ValueSource(ints = [10, 15, 30, 50, 100, 1000])
+    fun `format task can format multiple files using process isolation strategy`(n: Int) {
+        configureProcessIsolationStrategy()
+        repeat(n) { index ->
+            createTempFile(content = "val answer${index}=42\n", fileName = "TestFile$index.kt")
+        }
+        val result =
+            GradleRunner.create()
+                .withProjectDir(tempDir)
+                .withPluginClasspath()
+                .withArguments("ktfmtFormatMain", "--info")
+                .forwardOutput()
+                .build()
+
+        assertThat(result.task(":ktfmtFormatMain")?.outcome).isEqualTo(SUCCESS)
+    }
+
     @Test
     fun `format task reformats all the file even with a failure`() {
         val file1 = createTempFile(content = "val answer = `", fileName = "File1.kt")
@@ -242,6 +281,11 @@ internal class KtfmtFormatTaskIntegrationTest {
         assertThat(result.output).contains("[ktfmt] Successfully reformatted 1 files with Ktfmt")
     }
 
+    private fun configureProcessIsolationStrategy() {
+        File("src/test/resources/jvmProjectProcessIsolation")
+            .copyRecursively(tempDir, overwrite = true)
+    }
+
     private fun createTempFile(
         @Language("kotlin") content: String,
         fileName: String = "TestFile.kt",

plugin-build/plugin/src/test/resources/jvmProjectProcessIsolation/build.gradle.kts

@@ -0,0 +1,13 @@
+import com.ncorti.ktfmt.gradle.GradleWorkerIsolationStrategy
+
+plugins {
+    kotlin("jvm") version "1.7.20"
+    id("com.ncorti.ktfmt.gradle")
+}
+
+repositories { mavenCentral() }
+
+ktfmt {
+    kotlinLangStyle()
+    gradleWorkerIsolationStrategy.set(GradleWorkerIsolationStrategy.NO_ISOLATION)
+}

plugin-build/plugin/src/test/resources/jvmProjectProcessIsolation/settings.gradle.kts

@@ -0,0 +1,3 @@
+package jvmProjectProcessIsolation
+
+rootProject.name = ("test-fixtures")