Extract Skippy to separate, standalone JVM project + CLI (#717)

This allows us to invoke skippy completely independently from Gradle
(IFF we have a serialized graph and list of affected android test
projects cached/pre-computed).

This works by extracting skippy's core to a separate skippy artifact, as
well as a shared common utils artifact for shared APIs.

This implements a CLI along the way, based on the existing gradle task.
It works mostly the same way, but just via Clikt instead.

Opportunistically, I also split out the graph generation and android
test project path aggregation to separate ancestor tasks, which would
allow us to more granularly compute these before-hand and keep them
cached.

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gradle/libs.versions.toml

@@ -52,6 +52,7 @@ agpAlpha = { module = "com.android.tools.build:gradle", version.ref = "agpAlpha"
 autoService-annotations = "com.google.auto.service:auto-service-annotations:1.1.1"
 autoService-ksp = "dev.zacsweers.autoservice:auto-service-ksp:1.1.0"
 bugsnag = "com.bugsnag:bugsnag:3.7.1"
+clikt = "com.github.ajalt.clikt:clikt:4.2.2"
 commonsText = "org.apache.commons:commons-text:1.11.0"
 coroutines-bom = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-bom", version.ref = "coroutines" }
 coroutines-core = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-core" }

settings.gradle.kts

@@ -182,6 +182,8 @@ include(
   ":agp-handlers:agp-handler-82",
   ":agp-handlers:agp-handler-83",
   ":agp-handlers:agp-handler-api",
+  ":skippy",
+  ":sgp-common",
   ":skate-plugin",
   ":skate-plugin:artifactory-authenticator",
   ":slack-plugin",

sgp-common/build.gradle.kts

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2024 Slack Technologies, LLC
+ *
+ * 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
+ *
+ *    https://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.
+ */
+plugins {
+  kotlin("jvm")
+  alias(libs.plugins.mavenPublish)
+}
+
+dependencies {
+  api(platform(libs.coroutines.bom))
+  api(libs.okio)
+
+  implementation(libs.coroutines.core)
+}

sgp-common/gradle.properties

@@ -0,0 +1,3 @@
+POM_ARTIFACT_ID=sgp-common
+POM_NAME=SGP (Common)
+POM_DESCRIPTION=SGP (Common)

slack-plugin/src/main/kotlin/slack/gradle/util/Collections.kt → sgp-common/src/main/kotlin/com/slack/sgp/common/Collections.kt

@@ -13,20 +13,18 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package slack.gradle.util
+package com.slack.sgp.common
 
-import slack.gradle.avoidance.ComputeAffectedProjectsTask
-
-internal fun <T, R> Collection<T>.mapToSet(transform: (T) -> R): Set<R> {
+public fun <T, R> Collection<T>.mapToSet(transform: (T) -> R): Set<R> {
   return mapTo(mutableSetOf(), transform)
 }
 
-internal fun <T, R> Collection<T>.flatMapToSet(transform: (T) -> Iterable<R>): Set<R> {
+public fun <T, R> Collection<T>.flatMapToSet(transform: (T) -> Iterable<R>): Set<R> {
   return flatMapTo(mutableSetOf(), transform)
 }
 
 /**
- * Flips a map. In the context of [ComputeAffectedProjectsTask], we use this to flip a map of
+ * Flips a map. In the context of `ComputeAffectedProjectsTask`, we use this to flip a map of
  * projects to their dependencies to a map of projects to the projects that depend on them. We use
  * this to find all affected projects given a seed of changed projects.
  *
@@ -39,7 +37,7 @@ internal fun <T, R> Collection<T>.flatMapToSet(transform: (T) -> Iterable<R>): S
  *  {b:[a], c:[a], d:[b, c]}
  *  ```
  */
-internal fun Map<String, Set<String>>.flip(): Map<String, Set<String>> {
+public fun Map<String, Set<String>>.flip(): Map<String, Set<String>> {
   val flipped = mutableMapOf<String, MutableSet<String>>()
   for ((project, dependenciesSet) in this) {
     for (dependency in dependenciesSet) {

slack-plugin/src/main/kotlin/slack/gradle/util/ParallelIterables.kt → sgp-common/src/main/kotlin/com/slack/sgp/common/ParallelIterables.kt

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package slack.gradle.util
+package com.slack.sgp.common
 
 import kotlinx.coroutines.CoroutineStart
 import kotlinx.coroutines.async
@@ -25,7 +25,7 @@ import kotlinx.coroutines.sync.Semaphore
 /**
  * Applies a given [mapper] function in parallel over this [Iterable] with a given [parallelism].
  */
-internal suspend inline fun <A, B> Iterable<A>.parallelMap(
+public suspend inline fun <A, B> Iterable<A>.parallelMap(
   parallelism: Int,
   start: CoroutineStart = CoroutineStart.DEFAULT,
   crossinline mapper: suspend (A) -> B
@@ -48,7 +48,7 @@ internal suspend inline fun <A, B> Iterable<A>.parallelMap(
  * Applies a given [mapper] function in parallel over this [Iterable] with a given [parallelism],
  * filtering out null [B]s.
  */
-internal suspend inline fun <A, B> Iterable<A>.parallelMapNotNull(
+public suspend inline fun <A, B> Iterable<A>.parallelMapNotNull(
   parallelism: Int,
   start: CoroutineStart = CoroutineStart.DEFAULT,
   crossinline mapper: suspend (A) -> B?
@@ -72,7 +72,7 @@ internal suspend inline fun <A, B> Iterable<A>.parallelMapNotNull(
  * Iterates this [Iterable] with a given [parallelism], passing the value for each emission to the
  * given [action].
  */
-internal suspend inline fun <A> Iterable<A>.parallelForEach(
+public suspend inline fun <A> Iterable<A>.parallelForEach(
   parallelism: Int,
   start: CoroutineStart = CoroutineStart.DEFAULT,
   crossinline action: suspend (A) -> Unit

slack-plugin/src/main/kotlin/slack/gradle/util/Paths.kt → sgp-common/src/main/kotlin/com/slack/sgp/common/Paths.kt

@@ -13,17 +13,17 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package slack.gradle.util
+package com.slack.sgp.common
 
 import okio.FileSystem
 import okio.Path
 
-internal fun Path.prepareForGradleOutput(fs: FileSystem) = apply {
+public fun Path.prepareForGradleOutput(fs: FileSystem): Path = apply {
   if (fs.exists(this)) fs.delete(this)
   parent?.let(fs::createDirectories)
 }
 
-internal fun Path.readLines(fs: FileSystem): List<String> {
+public fun Path.readLines(fs: FileSystem): List<String> {
   return fs.read(this) {
     val lines = mutableListOf<String>()
     while (!exhausted()) {
@@ -33,7 +33,7 @@ internal fun Path.readLines(fs: FileSystem): List<String> {
   }
 }
 
-internal fun Path.writeLines(lines: Iterable<String>, fs: FileSystem) {
+public fun Path.writeLines(lines: Iterable<String>, fs: FileSystem) {
   fs.write(this) {
     lines.forEach { line ->
       writeUtf8(line)
@@ -42,6 +42,6 @@ internal fun Path.writeLines(lines: Iterable<String>, fs: FileSystem) {
   }
 }
 
-internal fun Path.writeText(text: String, fs: FileSystem) {
+public fun Path.writeText(text: String, fs: FileSystem) {
   fs.write(this) { writeUtf8(text) }
 }

slack-plugin/src/main/kotlin/slack/gradle/util/SgpLogger.kt → sgp-common/src/main/kotlin/com/slack/sgp/common/SgpLogger.kt

@@ -13,34 +13,32 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package slack.gradle.util
-
-import org.gradle.api.logging.Logger
+package com.slack.sgp.common
 
 /** A simple logging abstraction for use in SGP. */
-internal interface SgpLogger {
-  fun debug(message: String)
+public interface SgpLogger {
+  public fun debug(message: String)
 
-  fun info(message: String)
+  public fun info(message: String)
 
-  fun lifecycle(message: String)
+  public fun lifecycle(message: String)
 
-  fun warn(message: String)
+  public fun warn(message: String)
 
-  fun warn(message: String, error: Throwable)
+  public fun warn(message: String, error: Throwable)
 
-  fun error(message: String)
+  public fun error(message: String)
 
-  fun error(message: String, error: Throwable)
+  public fun error(message: String, error: Throwable)
 
-  companion object {
-    fun gradle(logger: Logger): SgpLogger = GradleSgpLogger(logger)
+  public companion object {
 
-    fun noop(): SgpLogger = NoopSgpLogger
+    public fun noop(): SgpLogger = NoopSgpLogger
 
-    fun system(): SgpLogger = SystemSgpLogger
+    public fun system(): SgpLogger = SystemSgpLogger
 
-    fun prefix(prefix: String, delegate: SgpLogger): SgpLogger = PrefixSgpLogger(prefix, delegate)
+    public fun prefix(prefix: String, delegate: SgpLogger): SgpLogger =
+      PrefixSgpLogger(prefix, delegate)
   }
 }
 
@@ -129,34 +127,3 @@ private object SystemSgpLogger : SgpLogger {
     error.printStackTrace(System.err)
   }
 }
-
-/** A Gradle [Logger]-based [SgpLogger]. */
-private class GradleSgpLogger(private val delegate: Logger) : SgpLogger {
-  override fun debug(message: String) {
-    delegate.debug(message)
-  }
-
-  override fun info(message: String) {
-    delegate.info(message)
-  }
-
-  override fun lifecycle(message: String) {
-    delegate.lifecycle(message)
-  }
-
-  override fun warn(message: String) {
-    delegate.warn(message)
-  }
-
-  override fun warn(message: String, error: Throwable) {
-    delegate.warn(message, error)
-  }
-
-  override fun error(message: String) {
-    delegate.error(message)
-  }
-
-  override fun error(message: String, error: Throwable) {
-    delegate.error(message, error)
-  }
-}

skippy/build.gradle.kts

@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2024 Slack Technologies, LLC
+ *
+ * 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
+ *
+ *    https://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.
+ */
+plugins {
+  kotlin("jvm")
+  alias(libs.plugins.moshix)
+  alias(libs.plugins.mavenPublish)
+}
+
+dependencies {
+  api(platform(libs.coroutines.bom))
+
+  implementation(libs.clikt)
+  implementation(libs.coroutines.core)
+  implementation(libs.gradlePlugins.graphAssert) { because("To use in Gradle graphing APIs.") }
+  implementation(libs.kotlinCliUtil)
+  implementation(libs.moshi)
+  implementation(libs.okio)
+  implementation(projects.sgpCommon)
+
+  testImplementation(platform(libs.coroutines.bom))
+  testImplementation(libs.coroutines.test)
+  testImplementation(libs.junit)
+  testImplementation(libs.okio.fakefilesystem)
+  testImplementation(libs.truth)
+}

skippy/gradle.properties

@@ -0,0 +1,3 @@
+POM_ARTIFACT_ID=sgp-skippy
+POM_NAME=SGP (Skippy)
+POM_DESCRIPTION=SGP (Skippy)

slack-plugin/src/main/kotlin/slack/gradle/avoidance/AffectedProjectsComputer.kt → skippy/src/main/kotlin/com/slack/skippy/AffectedProjectsComputer.kt

@@ -13,13 +13,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package slack.gradle.avoidance
+package com.slack.skippy
 
+import com.slack.sgp.common.SgpLogger
+import com.slack.skippy.SkippyConfig.Companion.GLOBAL_TOOL
 import kotlin.time.measureTimedValue
 import okio.FileSystem
 import okio.Path
-import slack.gradle.avoidance.SkippyConfig.Companion.GLOBAL_TOOL
-import slack.gradle.util.SgpLogger
 
 /**
  * This is a program compute the set of Gradle projects that are affected by a set of changed files
@@ -79,7 +79,7 @@ import slack.gradle.util.SgpLogger
  * @property debug Debugging flag. If enabled, extra diagnostics and logging is performed.
  * @property logger A logger to use for logging.
  */
-internal class AffectedProjectsComputer(
+public class AffectedProjectsComputer(
   private val rootDirPath: Path,
   private val dependencyMetadata: DependencyMetadata,
   private val changedFilePaths: List<Path>,
@@ -90,7 +90,7 @@ internal class AffectedProjectsComputer(
   private val fileSystem: FileSystem = FileSystem.SYSTEM,
   private val logger: SgpLogger = SgpLogger.noop(),
 ) {
-  fun compute(): AffectedProjectsResult? {
+  public fun compute(): AffectedProjectsResult? {
     return logTimedValue("full computation of ${config.tool}") { computeImpl() }
   }
 
@@ -285,7 +285,7 @@ internal class AffectedProjectsComputer(
     }
   }
 
-  companion object {
+  internal companion object {
     /** Returns a filtered list of [filePaths] that match the given [includePatterns]. */
     fun filterIncludes(filePaths: List<Path>, includePatterns: Collection<String>) =
       filePaths.filter { includePatterns.any { pattern -> pattern.toPathMatcher().matches(it) } }

slack-plugin/src/main/kotlin/slack/gradle/avoidance/AffectedProjectsDefaults.kt → skippy/src/main/kotlin/com/slack/skippy/AffectedProjectsDefaults.kt

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package slack.gradle.avoidance
+package com.slack.skippy
 
 import java.util.Collections.unmodifiableSet
 

slack-plugin/src/main/kotlin/slack/gradle/avoidance/AffectedProjectsResult.kt → skippy/src/main/kotlin/com/slack/skippy/AffectedProjectsResult.kt

@@ -13,11 +13,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package slack.gradle.avoidance
+package com.slack.skippy
 
 import java.util.SortedSet
 
-internal data class AffectedProjectsResult(
+public data class AffectedProjectsResult(
   val affectedProjects: SortedSet<String>,
   val focusProjects: SortedSet<String>,
   val affectedAndroidTestProjects: SortedSet<String>,