Handle point selections in projection pushdown

vegafusion-core/src/planning/projection_pushdown.rs

@@ -748,6 +748,10 @@ impl ChartVisitor for CollectVlSelectionTestFieldsVisitor {
         //   ]
         // }
         //
+        // or, for point selections
+        //
+        //   "value": [{"field": "year_date", "type": "E"}]
+        //
         // With a corresponding dataset named "{name}_store". If we fine this pair, then use the
         // "field" entries in {name}_tuple_fields as column usage fields.
         if signal.name.ends_with("_tuple_fields") {
@@ -765,9 +769,7 @@ impl ChartVisitor for CollectVlSelectionTestFieldsVisitor {
                     if let Ok(table) = VegaFusionTable::from_json(value) {
                         // Check that we have "field", "channel", and "type" columns
                         let schema = &table.schema;
-                        if schema.field_with_name("channel").is_ok()
-                            && schema.field_with_name("type").is_ok()
-                        {
+                        if schema.field_with_name("type").is_ok() {
                             if let Ok(field_index) = schema.index_of("field") {
                                 if let Ok(batch) = table.to_record_batch() {
                                     let field_array = batch.column(field_index);

vegafusion-core/src/spec/transform/project.rs

@@ -57,7 +57,7 @@ impl TransformSpecTrait for ProjectTransformSpec {
         self.fields
             .iter()
             .filter_map(|project_field| {
-                if input_local_datetime_columns.contains(project_field) {
+                if input_local_datetime_columns.contains(&unescape_field(project_field)) {
                     Some(project_field.clone())
                 } else {
                     None

vegafusion-runtime/tests/specs/custom/gh_456.comm_plan.json

@@ -0,0 +1,30 @@
+{
+  "server_to_client": [
+    {
+      "name": "column_domain",
+      "namespace": "data",
+      "scope": []
+    },
+    {
+      "name": "data_0_color_domain_symbol",
+      "namespace": "data",
+      "scope": []
+    },
+    {
+      "name": "data_0_facet_facet0",
+      "namespace": "data",
+      "scope": []
+    },
+    {
+      "name": "data_3_x_domain_symbol",
+      "namespace": "data",
+      "scope": []
+    },
+    {
+      "name": "data_3_y_domain_sum_price",
+      "namespace": "data",
+      "scope": []
+    }
+  ],
+  "client_to_server": []
+}