Fix parent scope resolution (#464)

vegafusion-core/src/planning/projection_pushdown.rs

@@ -220,7 +220,8 @@ impl GetDatasetsColumnUsage for MarkSpec {
             // the subset datasets are used.
             if let Some(facet) = self.from.as_ref().and_then(|from| from.facet.clone()) {
                 let facet_data_var = Variable::new_data(&facet.data);
-                if let Ok(resolved) = task_scope.resolve_scope(&facet_data_var, usage_scope) {
+                let parent_scope = &usage_scope[0..usage_scope.len() - 1];
+                if let Ok(resolved) = task_scope.resolve_scope(&facet_data_var, parent_scope) {
                     let scoped_facet_data_var = (resolved.var, resolved.scope);
                     usage = usage.with_unknown_usage(&scoped_facet_data_var);
                 }

vegafusion-runtime/tests/specs/custom/gh_463.comm_plan.json

@@ -0,0 +1,35 @@
+{
+  "server_to_client": [
+    {
+      "name": "data_0",
+      "namespace": "data",
+      "scope": []
+    },
+    {
+      "name": "data_0_color_domain_Major Genre",
+      "namespace": "data",
+      "scope": []
+    },
+    {
+      "name": "data_3",
+      "namespace": "data",
+      "scope": []
+    },
+    {
+      "name": "data_3_x_domain_MPAA Rating",
+      "namespace": "data",
+      "scope": []
+    },
+    {
+      "name": "facet_domain",
+      "namespace": "data",
+      "scope": []
+    },
+    {
+      "name": "facet_domain_row",
+      "namespace": "data",
+      "scope": []
+    }
+  ],
+  "client_to_server": []
+}