Merge pull request #514 from metabase/qp_cleanup_2000

A bit of cleanup in the QP.

src/metabase/driver/query_processor.clj

@@ -18,15 +18,10 @@
          expand
          get-special-column-info
          preprocess-cumulative-sum
-         preprocess-structured
-         remove-empty-clauses)
+         preprocess-structured)
 
 ;; # CONSTANTS
 
-(def ^:const empty-response
-  "An empty response dictionary to return when there's no query to run."
-  {:rows [], :columns [], :cols []})
-
 (def ^:const max-result-rows
   "Maximum number of rows the QP should ever return."
   10000)
@@ -71,7 +66,6 @@
                             ;; Functions that take place before expansion
                             ;; These functions expect just the :query subdictionary (TODO -- these need to be changed to use to expanded query at some point
                             (update-in query [:query] #(->> %
-                                                            remove-empty-clauses
                                                             add-implicit-breakout-order-by
                                                             add-implicit-limit
                                                             add-implicit-fields))
@@ -86,27 +80,6 @@
 
 ;; ## PREPROCESSOR FNS
 
-;; ### REMOVE-EMPTY-CLAUSES
-(def ^:private ^:const clause->empty-forms
-  "Clause values that should be considered empty and removed during preprocessing."
-  {:breakout #{[nil]}
-   :filter   #{[nil nil]}})
-
-(defn remove-empty-clauses
-  "Remove all QP clauses whose value is:
-   1.  is `nil`
-   2.  is an empty sequence (e.g. `[]`)
-   3.  matches a form in `clause->empty-forms`"
-  [query]
-  (->> query
-       (map (fn [[clause clause-value]]
-              (when (and clause-value
-                         (or (not (sequential? clause-value))
-                             (seq clause-value)))
-                (when-not (contains? (clause->empty-forms clause) clause-value)
-                  [clause clause-value]))))
-       (into {})))
-
 
 ;; ### ADD-IMPLICIT-BREAKOUT-ORDER-BY
 

src/metabase/driver/query_processor/expand.clj

@@ -79,6 +79,12 @@
 
 ;; ## -------------------- Expansion - Impl --------------------
 
+(defn- non-empty-clause? [clause]
+  (and clause
+       (or (not (sequential? clause))
+           (and (seq clause)
+                (every? identity clause)))))
+
 (defn- parse [query-dict]
   (update-in query-dict [:query] #(-<> (assoc %
                                               :aggregation (parse-aggregation (:aggregation %))
@@ -88,7 +94,7 @@
                                               :order_by    (parse-order-by    (:order_by %)))
                                        (set/rename-keys <> {:order_by     :order-by
                                                             :source_table :source-table})
-                                       (m/filter-vals identity <>))))
+                                       (m/filter-vals non-empty-clause? <>))))
 
 (def ^:private ^:dynamic *field-ids*
   "Bound to an atom containing a set when a parsing function is ran"
@@ -210,10 +216,7 @@
   "Convenience for writing a parser function, i.e. one that pattern-matches against a lone argument."
   [fn-name & match-forms]
   `(defn ~(vary-meta fn-name assoc :private true) [form#]
-     (when (and form#
-                (or (not (sequential? form#))
-                    (and (seq form#)
-                         (every? identity form#))))
+     (when (non-empty-clause? form#)
        (match form#
          ~@match-forms))))