Gradle Kotlin Versioning ❤ Composing Builds > BuildSrc 筆記

自從為了就是自動補全(auto-completion)的功能，我們開始使用 BuildSrc ，讓其他 gradle project 自動帶入識別 BuildSrc 底下的定義們：

buildSrc/src/main/java/Ext.kt

object Version {
    const val kotlinxCoroutines = "1.5.0"
    const val junit = "4.12"
    const val truth = "1.1.3"
    const val mockitoKotlin = "3.2.0"
    const val robolectric = "4.5.1"
}
object Depends {
    const val kotlinxCoroutinesCore = "org.jetbrains.kotlinx:kotlinx-coroutines-core:${Version.kotlinxCoroutines}"
    const val kotlinxCoroutinesCoreTest = "org.jetbrains.kotlinx:kotlinx-coroutines-test:${Version.kotlinxCoroutines}"
    const val junit = "junit:junit:${Version.junit}"
    const val truth = "com.google.truth:truth:${Version.truth}"
    const val mockitoKotlin = "org.mockito.kotlin:mockito-kotlin:${Version.mockitoKotlin}"
    const val robolectric = "org.robolectric:robolectric:${Version.robolectric}"
}

Gradle 文件提到：

A change in buildSrc causes the whole project to become out-of-date. Thus, when making small incremental changes, the --no-rebuild command-line option is often helpful to get faster feedback. Remember to run a full build regularly or at least when you’re done, though.

BuildSrc 一旦修改，整個 project 都會重新建構。

那如果我們把 BuildSrc Ext.kt 轉成獨立 Gradle Plugin Module，那麼每個變動只會重新建構該 Module ，這樣效能比較好。

我們有個最簡單的 Local Gradle Plugin 模式：Composing Builds：

Composing builds

第 1 步，將 buildSrc/ 更名成 version-gradle/ (版號 Gradle Plugin 的意思)，Ext.kt 改成 version.gradle.VersionGradle.kt ：

+ package version.gradle

+ import org.gradle.api.Plugin
+ import org.gradle.api.Project

+ class VersionGradle : Plugin<Project> {
+     override fun apply(project: Project) {
+     }
+ }

  object Version {
      // ...
  }

  object Depends {
      // ...
  }

第 2 步，/settings.gradle.kts 增加一行：

  rootProject.name = "aws-ktx"
+ includeBuild("version-gradle")

第 3 步，version-gradle/build.gradle.kts ：

plugins {
    `kotlin-dsl`
    `java-gradle-plugin`
}

repositories {
    mavenCentral()
}

gradlePlugin {
    plugins {
        create("version.gradle") {
            id = "version.gradle"
            implementationClass = "version.gradle.VersionGradle"
        }
    }
}

最後第 4 步，讓所有 modules 都認得 version.gradle plugin：

/build.gradle.kts

buildscript {
    // ...
}
+ plugins {
+     id("version.gradle")
+ }

所有 modules 都加：

*-other-modules/build.gradle.kts

+ import version.gradle.*
  // ...
  dependencies {
      // ...
      testImplementation(Depends.junit)
      testImplementation(Depends.truth)

That’s it.

版號統一管理方案，目前已知有：

1. Ext 方案 (無法自動補全)：buildscript { ext.xxxx = "" }
2. build.gradle.kts + buildSrc 方案
3. builld.gradle.kts + composing builds 方案 (效能較好，獨立 module 刷新)

可參考實際運作的專案：

GitHub - yongjhih/aws-ktx

References

How to use Composite builds as a replacement of buildSrc in Gradle

Developing Custom Gradle Plugins

• https://juejin.cn/post/6844904176250519565