Test plugin dependencies and casting the existing instance.

foundation-bifrost/build.gradle.kts

@@ -1,3 +1,5 @@
 dependencies {
   implementation("net.dv8tion:JDA:5.0.0-alpha.2")
+
+  compileOnly(project(":foundation-core"))
 }

foundation-bifrost/src/main/kotlin/cloud/kubelet/foundation/bifrost/FoundationBifrostPlugin.kt

@@ -1,9 +1,13 @@
 package cloud.kubelet.foundation.bifrost
 
+import cloud.kubelet.foundation.core.FoundationCorePlugin
 import org.bukkit.plugin.java.JavaPlugin
 
 class FoundationBifrostPlugin : JavaPlugin() {
   override fun onEnable() {
     slF4JLogger.info("Enabling!")
+
+    val foundation = server.pluginManager.getPlugin("Foundation") as FoundationCorePlugin
+    slF4JLogger.info("Plugin data path: ${foundation.pluginDataPath}")
   }
 }

foundation-core/src/main/kotlin/cloud/kubelet/foundation/core/FoundationCorePlugin.kt

@@ -7,14 +7,30 @@ import org.bukkit.command.CommandExecutor
 import org.bukkit.event.EventHandler
 import org.bukkit.event.Listener
 import org.bukkit.plugin.java.JavaPlugin
+import java.nio.file.Path
 
 class FoundationCorePlugin : JavaPlugin(), Listener {
+  private lateinit var _pluginDataPath: Path
+
+  var pluginDataPath: Path
+    /**
+     * Data path of the core plugin.
+     * Can be used as a sanity check of sorts for dependencies to be sure the plugin is loaded.
+     */
+    get() {
+      if (!::_pluginDataPath.isInitialized) {
+        throw Exception("FoundationCore is not loaded!")
+      }
+      return _pluginDataPath
+    }
+    private set(value) { _pluginDataPath = value }
+
   override fun onEnable() {
-    val dataPath = dataFolder.toPath()
-    val backupPath = dataPath.resolve(BACKUPS_DIRECTORY)
+    pluginDataPath = dataFolder.toPath()
+    val backupPath = pluginDataPath.resolve(BACKUPS_DIRECTORY)
 
     // Create Foundation plugin directories.
-    dataPath.toFile().mkdir()
+    pluginDataPath.toFile().mkdir()
     backupPath.toFile().mkdir()
 
     // Register this as an event listener.