get-else throws if nil is used for default value

alexei-matveev · Jan 24, 2016 · 4d27be6 · 4d27be6
1 parent a98dc77
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# WIP
+
+- `get-else` throws if `nil` is used for default value
+
 # 0.15.0
 
 - Better error messages for upsert conflicts

diff --git a/src/datascript/query.cljc b/src/datascript/query.cljc
@@ -120,6 +120,8 @@
 
 (defn- -get-else
   [db e a else-val]
+  (when (nil? else-val)
+    (raise "get-else: nil default value is not supported" {:error :query/where}))
   (if-let [datom (first (db/-search db [e a]))]
     (:v datom)
     else-val))

diff --git a/test/datascript/test/query_fns.cljc b/test/datascript/test/query_fns.cljc
@@ -30,7 +30,12 @@
       (is (= (d/q '[:find ?e ?age ?height
                     :where [?e :age ?age]
                            [(get-else $ ?e :height 300) ?height]] db)
-             #{[1 15 300] [2 22 240] [3 37 300]})))
+             #{[1 15 300] [2 22 240] [3 37 300]}))
+
+      (is (thrown-with-msg? ExceptionInfo #"get-else: nil default value is not supported"
+            (d/q '[:find ?e ?height
+                    :where [?e :age]
+                           [(get-else $ ?e :height nil) ?height]] db))))
 
     (testing "get-some"
       (is (= (d/q '[:find ?e ?a ?v