Minecraft模组开发Gradle运行配置报TrialMod项目不存在错误解决

问题现象 #

• 参照基于Gradle的Forge模组开发教程操作，教程给出的空模组启动路径为：Run > Run Configuration > Java Application > run client
• 进入运行配置页面后，无任何预置配置项；手动新建运行配置时弹出错误提示：Launch configuration Trial references non-existing project TrialMod.
• 界面后台可看到项目实际存在，相关截图：
  • 配置菜单截图
  • 报错信息截图
• 当前使用的build.gradle配置内容：

// For those who want the bleeding edge
buildscript {
    repositories {
        jcenter()
        maven {
            name = "forge"
            url = "http://files.minecraftforge.net/maven"
        }
    }
    dependencies {
        classpath 'net.minecraftforge.gradle:ForgeGradle:2.1-SNAPSHOT'
    }
}
apply plugin: 'net.minecraftforge.gradle.forge'

/*
// for people who want stable - not yet functional for MC 1.8.8 - we require the forgegradle 2.1 snapshot
plugins {
    id "net.minecraftforge.gradle.forge" version "2.0.2"
}
*/
version = "2.0"
group= "com.oopermass.trialmod" // http://maven.apache.org/guides/mini/guide-naming-conventions.html
archivesBaseName = "trialmod"

minecraft {
    version = "1.8.9-11.15.1.2318-1.8.9"
    runDir = "run"
    
    // the mappings can be changed at any time, and must be in the following format.
    // snapshot_YYYYMMDD   snapshot are built nightly.
    // stable_#            stables are built at the discretion of the MCP team.
    // Use non-default mappings at your own risk. they may not allways work.
    // simply re-run your setup task after changing the mappings to update your workspace.
    mappings = "stable_20"
    // makeObfSourceJar = false // an Srg named sources jar is made by default. uncomment this to disable.
}

dependencies {
    // you may put jars on which you depend on in ./libs
    // or you may define them like so..
    //compile "some.group:artifact:version:classifier"
    //compile "some.group:artifact:version"
      
    // real examples
    //compile 'com.mod-buildcraft:buildcraft:6.0.8:dev'  // adds buildcraft to the dev env
    //compile 'com.googlecode.efficient-matrix-library:ejml:0.24' // adds ejml to the dev env

    // the 'provided' configuration is for optional dependencies that exist at compile-time but might not at runtime.
    //provided 'com.mod-buildcraft:buildcraft:6.0.8:dev'

    // the deobf configurations:  'deobfCompile' and 'deobfProvided' are the same as the normal compile and provided,
    // except that these dependencies get remapped to your current MCP mappings
    //deobfCompile 'com.mod-buildcraft:buildcraft:6.0.8:dev'
    //deobfProvided 'com.mod-buildcraft:buildcraft:6.0.8:dev'

    // for more info...
    // http://www.gradle.org/docs/current/userguide/artifact_dependencies_tutorial.html
    // http://www.gradle.org/docs/current/userguide/dependency_management.html

}

processResources
{
    // this will ensure that this task is redone when the versions change.
    inputs.property "version", project.version
    inputs.property "mcversion", project.minecraft.version

    // replace stuff in mcmod.info, nothing else
    from(sourceSets.main.resources.srcDirs) {
        include 'mcmod.info'
                
        // replace version and mcversion
        expand 'version':project.version, 'mcversion':project.minecraft.version
    }
        
    // copy everything else, thats not the mcmod.info
    from(sourceSets.main.resources.srcDirs) {
        exclude 'mcmod.info'
    }
}

故障原因 #

该问题和build.gradle配置内容无关，核心原因是导入项目后没有执行ForgeGradle的工作区初始化任务，IDE既没有自动生成预置的客户端/服务端运行配置，也没有完成项目结构的正确关联，手动新建配置时填写的项目名和Gradle实际识别的项目名不匹配，就会触发“引用不存在项目”的报错。

修复步骤 #

按顺序执行以下操作即可解决：

1. 关闭所有运行配置弹窗，回到IDE主界面，打开内置终端，确认终端当前路径为项目根目录（和build.gradle文件同层级）
2. 依次执行Gradle任务：
   • 执行清理命令：gradlew clean
   • 根据你使用的IDE执行对应的工作区初始化命令：
     • 使用IDEA开发：gradlew setupDecompWorkspace idea
     • 使用Eclipse开发：gradlew setupDecompWorkspace eclipse
       注意：该步骤需要联网下载Minecraft、Forge的依赖与反编译资源，耗时根据网络情况从数分钟到数十分钟不等，不要中途中断执行
3. 任务全部执行完成后，刷新Gradle项目：
   • IDEA用户点击右侧Gradle面板的刷新按钮，重新加载所有项目依赖
   • Eclipse用户右键项目，选择Gradle > Refresh Gradle Project
4. 不要手动新建运行配置，重新打开Run > Run Configuration页面，Java Application分类下会自动生成run client、run server两个预置配置，直接选中run client即可正常启动测试客户端。

常见踩坑提示：如果完成上述操作后仍看不到自动生成的运行配置，检查项目导入方式是否正确：必须将build.gradle所在的根目录作为Gradle项目导入，不要将内层src文件夹或其他子目录单独作为项目导入，否则IDE无法识别正确的项目结构，运行配置也无法关联到对应项目。

内容的提问来源于stack exchange，提问作者CubeTastick N