Check for offline mode before initializing submodules

paperweight-core/src/main/kotlin/io/papermc/paperweight/core/PaperweightCore.kt

@@ -35,12 +35,17 @@ import io.papermc.paperweight.util.constants.*
 import java.io.File
 import org.gradle.api.Plugin
 import org.gradle.api.Project
+import org.gradle.api.logging.Logging
 import org.gradle.api.tasks.Delete
 import org.gradle.api.tasks.TaskProvider
 import org.gradle.api.tasks.bundling.Zip
 import org.gradle.kotlin.dsl.*
 
 class PaperweightCore : Plugin<Project> {
+    companion object {
+        private val logger = Logging.getLogger(PaperweightCore::class.java)
+    }
+
     override fun apply(target: Project) {
         checkJavaVersion()
         Git.checkForGit()
@@ -58,7 +63,7 @@ class PaperweightCore : Plugin<Project> {
 
         // Make sure the submodules are initialized, since there are files there
         // which are required for configuration
-        target.layout.initSubmodules()
+        target.layout.maybeInitSubmodules(target.offlineMode(), logger)
 
         target.configurations.create(PARAM_MAPPINGS_CONFIG)
         target.configurations.create(REMAPPER_CONFIG)

paperweight-core/src/main/kotlin/io/papermc/paperweight/core/taskcontainers/GeneralTasks.kt

@@ -40,7 +40,9 @@ open class GeneralTasks(
 ) : InitialTasks(project) {
 
     // Configuration won't necessarily always run, so do it as the first task when it's needed as well
-    val initSubmodules by tasks.registering<InitSubmodules>()
+    val initSubmodules by tasks.registering<InitSubmodules> {
+        offlineMode.set(project.offlineMode())
+    }
 
     val buildDataInfo: Provider<BuildDataInfo> = project.contents(extension.craftBukkit.buildDataInfo) {
         gson.fromJson(it)

paperweight-lib/src/main/kotlin/io/papermc/paperweight/tasks/InitSubmodules.kt

@@ -26,17 +26,27 @@ import io.papermc.paperweight.util.*
 import javax.inject.Inject
 import org.gradle.api.DefaultTask
 import org.gradle.api.file.ProjectLayout
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.Input
 import org.gradle.api.tasks.TaskAction
 import org.gradle.api.tasks.UntrackedTask
 
+@Suppress("LeakingThis")
 @UntrackedTask(because = "Git tracks the state")
 abstract class InitSubmodules : DefaultTask() {
 
     @get:Inject
     abstract val layout: ProjectLayout
 
+    @get:Input
+    abstract val offlineMode: Property<Boolean>
+
+    init {
+        offlineMode.convention(false)
+    }
+
     @TaskAction
     fun run() {
-        layout.initSubmodules()
+        layout.maybeInitSubmodules(offlineMode.get(), logger)
     }
 }

paperweight-lib/src/main/kotlin/io/papermc/paperweight/util/utils.kt

@@ -60,6 +60,7 @@ import org.gradle.api.file.RegularFile
 import org.gradle.api.file.RegularFileProperty
 import org.gradle.api.invocation.Gradle
 import org.gradle.api.logging.LogLevel
+import org.gradle.api.logging.Logger
 import org.gradle.api.plugins.JavaPluginExtension
 import org.gradle.api.provider.Property
 import org.gradle.api.provider.Provider
@@ -94,11 +95,23 @@ val ProjectLayout.cache: Path
     get() = projectDirectory.dir(".gradle/$CACHE_PATH").path
 
 fun ProjectLayout.cacheDir(path: String) = projectDirectory.dir(".gradle/$CACHE_PATH").dir(path)
+
+fun ProjectLayout.maybeInitSubmodules(offline: Boolean, logger: Logger) {
+    if (offline) {
+        Git.checkForGit()
+        logger.lifecycle("Offline mode enabled, not initializing submodules. This may cause problems if submodules are not already initialized.")
+    } else {
+        initSubmodules()
+    }
+}
+
 fun ProjectLayout.initSubmodules() {
     Git.checkForGit()
     Git(projectDirectory.path)("submodule", "update", "--init").executeOut()
 }
 
+fun Project.offlineMode(): Boolean = gradle.startParameter.isOffline
+
 fun <T : FileSystemLocation> Provider<out T>.fileExists(project: Project): Provider<out T?> {
     return flatMap { project.provider { it.takeIf { f -> f.path.exists() } } }
 }