Fixed not-join not working properly with empty relations (closes #481)

Author: tonsky

CHANGELOG.md

@@ -1,6 +1,7 @@
 # WIP
 
 - Patch es6 iterators not having Symbol.iterator function #479 #249 via @kasbah
+- Fixed not-join not working properly with empty relations #481
 
 # 1.7.3 - Jul 22, 2024
 

deps.edn

@@ -20,11 +20,15 @@
   {:override-deps
    {org.clojure/clojure {:mvn/version "1.11.1"}}}
 
+  :1.12
+  {:override-deps
+   {org.clojure/clojure {:mvn/version "1.12.0"}}}
+
   :dev
   {:extra-paths ["dev" "test"]
    :jvm-opts    ["-ea" "-Ddatascript.debug" "-Dclojure.main.report=stderr"]
    :extra-deps
-   {io.github.tonsky/duti      {:git/sha "fc833a87a8687b67e66281e216eeee1ad6048168"}
+   {io.github.tonsky/duti      {:git/sha "e36d65296a4f9758664309ec35b00887e88c405a"}
     metosin/jsonista           {:mvn/version "0.3.3"}
     cheshire/cheshire          {:mvn/version "5.10.0"}
     com.cognitect/transit-clj  {:mvn/version "1.0.324"}
@@ -37,9 +41,8 @@
               "-Djdk.attach.allowAttachSelf"
               "-XX:+DebugNonSafepoints"]
    :extra-deps
-   {metosin/jsonista    {:mvn/version "0.3.3"}
-    criterium/criterium {:mvn/version "0.4.6"}
-    com.clojure-goes-fast/clj-async-profiler {:mvn/version "1.0.0"}}}
+   {metosin/jsonista {:mvn/version "0.3.3"}
+    io.github.tonsky/duti {:git/sha "e36d65296a4f9758664309ec35b00887e88c405a"}}}
 
   :datomic
   {:extra-paths ["bench_datomic" "test_datomic"]

dev/user.clj

@@ -1,6 +1,6 @@
 (ns user
   (:require
-    [duti.core :as duti]))
+   [duti.core :as duti]))
 
 (duti/set-dirs "src" "bench" "test" #_"bench_datomic" #_"test_datomic")
 

script/repl.sh

@@ -2,4 +2,4 @@
 set -o errexit -o nounset -o pipefail
 cd "`dirname $0`/.."
 
-clojure -A:1.11.1:dev:bench -M -m user
+clojure -M:1.12:dev:bench:datomic -m user

src/datascript/query.cljc

@@ -41,6 +41,14 @@
 ;; or [(Datom. 2 "Oleg" 1 55) ...]
 (defrecord Relation [attrs tuples])
 
+#?(:clj
+   (defmethod print-method Relation [r, ^java.io.Writer w]
+     (.write w "#Relation{:attrs ")
+     (.write w (pr-str (:attrs r)))
+     (.write w ", :tuples [")
+     (.write w (str/join " " (map seq (:tuples r))))
+     (.write w "]}")))
+
 
 ;; Utilities
 
@@ -804,15 +812,25 @@
                                   *lookup-attrs*)]
          (update context :rels collapse-rels relation))))))
 
+(defn short-circuit-empty-rel [context]
+  (if (some #(empty? (:tuples %)) (:rels context))
+    (assoc context
+      :rels
+      [(Relation.
+         (zipmap (mapcat #(keys (:attrs %)) (:rels context)) (range))
+         [])])
+    context))
+
 (defn resolve-clause [context clause]
   (if (->> (:rels context) (some (comp empty? :tuples)))
     context ; The result is empty; short-circuit processing
-    (if (rule? context clause)
-      (if (source? (first clause))
-        (binding [*implicit-source* (get (:sources context) (first clause))]
-          (resolve-clause context (next clause)))
-        (update context :rels collapse-rels (solve-rule context clause)))
-      (-resolve-clause context clause))))
+    (short-circuit-empty-rel
+      (if (rule? context clause)
+        (if (source? (first clause))
+          (binding [*implicit-source* (get (:sources context) (first clause))]
+            (resolve-clause context (next clause)))
+          (update context :rels collapse-rels (solve-rule context clause)))
+        (-resolve-clause context clause)))))
 
 (defn -q [context clauses]
   (binding [*implicit-source* (get (:sources context) '$)]

test/datascript/test/query_not.cljc

@@ -48,7 +48,8 @@
 
     ;; exclude empty set
     [[?e :name]
-     (not [?e :name "Ivan"]
+     (not
+       [?e :name "Ivan"]
        [?e :name "Oleg"])]
     #{1 2 3 4 5 6}
 
@@ -65,8 +66,7 @@
     #{2 4 6}))
 
 (deftest test-not-join
-  (are [q res] (= (d/q (concat '[:find ?e ?a :where] (quote q)) @*test-db)
-                 res)
+  (are [q res] (= res (d/q (concat '[:find ?e ?a :where] (quote q)) @*test-db))
     [[?e :name]
      [?e :age  ?a]
      (not-join [?e]
@@ -80,7 +80,14 @@
        [?e :name "Oleg"]
        [?e :age  ?a]
        [?e :age  10])]
-    #{[1 10] [5 10]}))
+    #{[1 10] [5 10]}
+    
+    ;; issue-481
+    [[?e :age ?a]
+     (not-join [?a]
+       [?e :name "Petr"]
+       [?e :age ?a])]
+    #{[1 10] [2 20] [3 10] [4 20] [5 10] [6 20]}))
 
 (deftest test-default-source
   (let [db1 (d/db-with (d/empty-db)