Reserve names starting with a dollar sign, closes rojo-rbx#191.

CHANGELOG.md

@@ -8,6 +8,7 @@
 * Added support for live-syncing `CollectionService` tags.
 * Added a warning when building binary place files, since they're still experimental and have bugs.
 * Added a warning when trying to use Rojo 0.5.x with a Rojo 0.4.x-only project.
+* Added a warning when a Rojo project contains keys that start with `$`, which are reserved names. ([#191](https://github.com/LPGhatguy/rojo/issues/191))
 * Added an icon to the plugin's toolbar button
 * Changed the plugin to use a docking widget for all UI.
 * Changed the plugin to ignore unknown properties when live-syncing.

server/src/project.rs

@@ -20,7 +20,7 @@ pub static COMPAT_PROJECT_FILENAME: &'static str = "roblox-project.json";
 /// want to do things like transforming paths to be absolute before handing them
 /// off to the rest of Rojo, we use this intermediate struct.
 #[derive(Debug, Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
+#[serde(deny_unknown_fields, rename_all = "camelCase")]
 struct SourceProject {
     name: String,
     tree: SourceProjectNode,
@@ -274,6 +274,17 @@ pub struct ProjectNode {
 }
 
 impl ProjectNode {
+    fn validate_reserved_names(&self) {
+        for (name, child) in &self.children {
+            if name.starts_with('$') {
+                warn!("Keys starting with '$' are reserved by Rojo to ensure forward compatibility.");
+                warn!("This project uses the key '{}', which should be renamed.", name);
+            }
+
+            child.validate_reserved_names();
+        }
+    }
+
     fn to_source_node(&self, project_file_location: &Path) -> SourceProjectNode {
         let children = self.children.iter()
             .map(|(key, value)| (key.clone(), value.to_source_node(project_file_location)))
@@ -513,6 +524,8 @@ impl Project {
             warn!(".project.json extension. This helps Rojo differentiate project files from");
             warn!("other JSON files!");
         }
+
+        self.tree.validate_reserved_names();
     }
 
     /// Issues a warning if no Rojo 0.5.x project is found, but there's a legacy

test-projects/legacy-0.5.x-reserved-names/default.project.json

@@ -0,0 +1,9 @@
+{
+  "name": "legacy-0.5.x-reserved-names",
+  "tree": {
+    "$className": "Folder",
+    "$warn-about-me": {
+      "$className": "Folder"
+    }
+  }
+}