Add expression_name to QP cols results

frontend/src/metabase-lib/lib/queries/StructuredQuery.js

@@ -738,8 +738,8 @@ export default class StructuredQuery extends AtomicQuery {
       return ["fk->", column.fk_field_id, column.id];
     } else if (column.id != null) {
       return ["field-id", column.id];
-    } else if (column["expression-name"] != null) {
-      return ["expression", column["expression-name"]];
+    } else if (column.expression_name != null) {
+      return ["expression", column.expression_name];
     } else if (column.source === "aggregation") {
       // FIXME: aggregations > 0?
       return ["aggregation", 0];

frontend/src/metabase/lib/dataset.js

@@ -53,8 +53,8 @@ export function fieldRefForColumn(column: Column): ?ConcreteField {
     } else {
       return ["field-id", column.id];
     }
-  } else if (column["expression-name"] != null) {
-    return ["expression", column["expression-name"]];
+  } else if (column.expression_name != null) {
+    return ["expression", column.expression_name];
   } else {
     return null;
   }

frontend/src/metabase/meta/types/Dataset.js

@@ -24,7 +24,7 @@ export type Column = {
   unit?: DatetimeUnit,
   binning_info?: BinningInfo,
   fk_field_id?: FieldId,
-  "expression-name"?: any,
+  expression_name?: any,
   settings?: ColumnSettings,
 };
 

src/metabase/query_processor/middleware/annotate.clj

@@ -90,10 +90,12 @@
      :display_name (humanization/name->human-readable-name field-name)}
 
     [:expression expression-name]
-    {:name         expression-name
-     :display_name expression-name
-     :base_type    :type/Float
-     :special_type :type/Number}
+    {:name            expression-name
+     :display_name    expression-name
+     :base_type       :type/Float
+     :special_type    :type/Number
+     ;; provided so the FE can add easily add sorts and the like when someone clicks a column header
+     :expression_name expression-name}
 
     [:field-id id]
     (dissoc (qp.store/field id) :database_type)

test/metabase/query_processor/middleware/annotate_test.clj

@@ -2,11 +2,11 @@
   (:require [expectations :refer [expect]]
             [metabase.models.field :refer [Field]]
             [metabase.query-processor
-             [interface :as i]
-             [store :as qp.store]]
+             [interface :as qp.i]
+             [store :as qp.store]
+             [test-util :as qp.test-util]]
             [metabase.query-processor.middleware.annotate :as annotate]
-            [metabase.test.data :as data]
-            [metabase.query-processor.interface :as qp.i])
+            [metabase.test.data :as data])
   (:import metabase.driver.h2.H2Driver))
 
 ;;; +----------------------------------------------------------------------------------------------------------------+
@@ -239,3 +239,23 @@
       :type     :query
       :query    {:source-table (data/id :venues)
                  :aggregation  [[:count] [:sum] [:count] [:named [:count] "count_2"]]}})))
+
+;; make sure expressions come back with the right set of keys, including `:expression_name` (#8854)
+(expect
+  {:name            "discount_price"
+   :display_name    "discount_price"
+   :base_type       :type/Float
+   :special_type    :type/Number
+   :expression_name "discount_price"
+   :source          :fields}
+  (-> (qp.test-util/with-everything-store
+        ((annotate/add-column-info (constantly {}))
+         {:database (data/id)
+          :type     :query
+          :query    (data/$ids [venues {:wrap-field-ids? true}]
+                      {:source-table $$table
+                       :expressions  {"discount_price" [:* 0.9 [:field-id $price]]}
+                       :fields       [$name [:expression "discount_price"]]
+                       :limit        10})}))
+      :cols
+      second))