Move project path validation to core library

Author: tomwyr

src/main/kotlin/com/tomwyr/command/Command.kt

@@ -36,9 +36,8 @@ class GenerateTreeCommand(
 
         private fun getProjectPath(rootPath: String, relativePath: String?): String {
             val fileName = "project.godot"
-            val path = Paths.get(rootPath, relativePath ?: "", fileName).toString()
-            if (!File(path).exists()) throw InvalidGodotProject()
-            return path
+            val path = Paths.get(rootPath, relativePath ?: "", fileName)
+            return path.toString()
         }
 
         private fun getOutputPath(rootPath: String, packageName: String?): String {

src/main/kotlin/com/tomwyr/common/Errors.kt

@@ -4,18 +4,16 @@ import kotlinx.serialization.Serializable
 
 sealed class GodotKotlinTreeError : Exception() {
     override fun getLocalizedMessage(): String = when (this) {
-        is InvalidGodotProject -> "The project in which GodotNodeTree annotation was used isn't a valid Godot project directory"
         is GeneratorError -> error.localizedMessage
     }
 }
 
-class InvalidGodotProject : GodotKotlinTreeError()
-
 class GeneratorError(val error: GodotNodeTreeError) : GodotKotlinTreeError()
 
 @Serializable
 sealed class GodotNodeTreeError : Exception() {
     override fun getLocalizedMessage(): String = when (this) {
+        is InvalidGodotProject -> "Godot project could not be found at path `$projectPath`."
         is ScanningScenesFailed -> "Unable to scan scene files for project at `$projectPath`."
         is ReadingSceneFailed -> "Unable to read contens of scene at `$scenePath`."
         is UnexpectedNodeParameters -> "A node with unexpected set of parameters encountered: $nodeParams."
@@ -24,6 +22,9 @@ sealed class GodotNodeTreeError : Exception() {
     }
 }
 
+@Serializable
+class InvalidGodotProject(val projectPath: String) : GodotNodeTreeError()
+
 @Serializable
 class ScanningScenesFailed(val projectPath: String) : GodotNodeTreeError()