Throw on referencing undefined rule (closes #319)

CHANGELOG.md

@@ -3,6 +3,7 @@
 - Support return maps (:keys/:syms/:strs) in query #322 #345
 - Throw when init-db is used with anything but datoms #276
 - Throw on using unindexed attribute in :avet index access #344
+- Throw on referencing undefined rule #319
 
 # 0.18.13
 

src/datascript/query.cljc

@@ -4,7 +4,7 @@
    [clojure.set :as set]
    [clojure.string :as str]
    [clojure.walk :as walk]
-   [datascript.db :as db #?(:cljs :refer-macros :clj :refer) [raise]]
+   [datascript.db :as db #?(:cljs :refer-macros :clj :refer) [raise cond+]]
    [me.tonsky.persistent-sorted-set.arrays :as da]
    [datascript.lru]
    [datascript.impl.entity :as de]
@@ -562,11 +562,29 @@
 ;;; RULES
 
 (defn rule? [context clause]
-  (and (sequential? clause)
-       (contains? (:rules context)
-                  (if (source? (first clause))
-                    (second clause)
-                    (first clause)))))
+  (cond+
+    (not (sequential? clause))
+    false
+
+    :let [head (if (source? (first clause))
+                  (second clause)
+                  (first clause))]
+
+    (not (symbol? head))
+    false
+
+    (free-var? head)
+    false
+
+    (contains? #{'_ 'or 'or-join 'and 'not 'not-join} head)
+    false
+
+    (not (contains? (:rules context) head))
+    (raise "Unknown rule '" head " in " clause
+      {:error :query/where
+       :form  clause})
+
+    :else true))
 
 (def rule-seqid (atom 0))
 

test/datascript/test/query_rules.cljc

@@ -160,7 +160,13 @@
                      [?y ?a]
                      [(>= ?a 18)]]])
            #{["Oleg"]})))
-  )
+
+  (testing "Rule name validation #319"
+    (is (thrown-msg? "Unknown rule 'wat in (wat ?x)"
+          (d/q '[:find  ?x
+                 :in    $ %
+                 :where (wat ?x)]
+            [] [])))))
 
 ;; https://github.com/tonsky/datascript/issues/218
 (deftest test-false-arguments
@@ -169,10 +175,11 @@
                  [:db/add 2 :attr false]])
         rules '[[(is ?id ?val)
                  [?id :attr ?val]]]]
-    (is (= (d/q '[:find ?id :in $ %
-                  :where (is ?id true)]
-                db rules)
-           #{[1]}))
-    (is (= (d/q '[:find ?id :in $ %
-                  :where (is ?id false)] db rules)
-           #{[2]}))))
+    (is (= #{[1]}
+          (d/q '[:find ?id :in $ %
+                 :where (is ?id true)]
+            db rules)))
+    (is (= #{[2]}
+          (d/q '[:find ?id :in $ %
+                 :where (is ?id false)]
+            db rules)))))