From 9ae1fd56f630c71358e233fc89d83fb5766405bd Mon Sep 17 00:00:00 2001
From: Nikita Prokopov <niki@tonsky.me>
Date: Tue, 18 Jun 2024 22:07:35 +0200
Subject: [PATCH] Allow lookup-refs inside tuples used for lookup-refs (closes
 #452)

---
 CHANGELOG.md                     |  1 +
 src/datascript/db.cljc           | 37 ++++++++++++++++++++++++++------
 test/datascript/test/tuples.cljc | 31 ++++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 21b67bb4..9b6dd444 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 - Correctly restore `:max-tx` from storage
 - Fixed tempid/upsert resolution when multiple tempids are added first #472
 - Allow upsert by implicit tuple when only tuple components are specified #473
+- Allow lookup-refs inside tuples used for lookup-refs #452
 
 # 1.6.5 - May 3, 2024
 
diff --git a/src/datascript/db.cljc b/src/datascript/db.cljc
index 14829296..dbf218b8 100644
--- a/src/datascript/db.cljc
+++ b/src/datascript/db.cljc
@@ -1238,6 +1238,14 @@
     (raise "Bad attribute type: " attr ", expected keyword or string"
       {:error :transact/syntax, :attribute attr})))
 
+(defn resolve-tuple-refs [db a vs]
+  (mapv
+    (fn [a v]
+      (if (and (ref? db a) (sequential? v)) ;; lookup-ref
+        (entid-strict db v)
+        v))
+    (-> db -schema (get a) :db/tupleAttrs) vs))
+
 (defn+ ^number entid [db eid]
   {:pre [(db? db)]}
   (cond
@@ -1250,15 +1258,22 @@
     (let [[attr value] eid]
       (cond
         (not= (count eid) 2)
-          (raise "Lookup ref should contain 2 elements: " eid
-            {:error :lookup-ref/syntax, :entity-id eid})
+        (raise "Lookup ref should contain 2 elements: " eid
+          {:error :lookup-ref/syntax, :entity-id eid})
+        
         (not (is-attr? db attr :db/unique))
-          (raise "Lookup ref attribute should be marked as :db/unique: " eid
-            {:error :lookup-ref/unique, :entity-id eid})
+        (raise "Lookup ref attribute should be marked as :db/unique: " eid
+          {:error :lookup-ref/unique, :entity-id eid})
+        
+        (tuple? db attr)
+        (let [value' (resolve-tuple-refs db attr value)]
+          (-> (-datoms db :avet attr value' nil nil) first :e))
+        
         (nil? value)
-          nil
+        nil
+        
         :else
-          (-> (-datoms db :avet attr value nil nil) first :e)))
+        (-> (-datoms db :avet attr value nil nil) first :e)))
     
     #?@(:cljs [(array? eid) (recur db (array-seq eid))])
     
@@ -1838,6 +1853,13 @@
                                (allocate-eid v resolved)
                                (update ::value-tempids assoc resolved v))]
                 (recur report' es)))
+            
+            (and
+              (or (= op :db/add) (= op :db/retract))
+              (not (::internal (meta entity)))
+              (tuple? db a)
+              (not= v (resolve-tuple-refs db a v)))
+            (recur report (cons [op e a (resolve-tuple-refs db a v)] entities))
 
             (tempid? e)
             (let [upserted-eid  (when (is-attr? db a :db.unique/identity)
@@ -1861,7 +1883,8 @@
                 (raise "Conflicting upsert: " e " resolves to " upserted-eid " via " entity
                   {:error :transact/upsert})))
             
-            (and (not (::internal (meta entity)))
+            (and
+              (not (::internal (meta entity)))
               (tuple? db a))
             ;; allow transacting in tuples if they fully match already existing values
             (let [tuple-attrs (get-in db [:schema a :db/tupleAttrs])]
diff --git a/test/datascript/test/tuples.cljc b/test/datascript/test/tuples.cljc
index e47f4ee8..13fa6153 100644
--- a/test/datascript/test/tuples.cljc
+++ b/test/datascript/test/tuples.cljc
@@ -293,6 +293,37 @@
             :c     "c"}
           (d/pull (d/db conn) '[*] [:a+b ["a" "b"]])))))
 
+;; https://github.com/tonsky/datascript/issues/452
+(deftest lookup-refs-in-tuple
+  (let [schema {:ref      {:db/valueType :db.type/ref}
+                :name     {:db/unique :db.unique/identity}
+                :ref+name {:db/valueType :db.type/tuple
+                           :db/tupleAttrs [:ref :name]
+                           :db/unique :db.unique/identity}}
+        db     (-> (d/empty-db schema)
+                 (d/db-with
+                   [{:db/id -1 :name "Ivan"}
+                    {:db/id -2 :name "Oleg"}
+                    {:db/id -3 :name "Petr" :ref -1}
+                    {:db/id -4 :name "Yuri" :ref -2}]))]
+    (let [db' (d/db-with db [{:ref+name [1 "Petr"], :age 32}])]
+      (is (= {:age 32} (d/pull db' [:age] 3))))
+    
+    (let [db' (d/db-with db [{:ref+name [[:name "Ivan"] "Petr"], :age 32}])]
+      (is (= {:age 32} (d/pull db' [:age] 3))))
+    
+    (let [db' (d/db-with db [[:db/add -1 :ref+name [1 "Petr"]]
+                             [:db/add -1 :age 32]])]
+      (is (= {:age 32} (d/pull db' [:age] 3))))
+    
+    (let [db' (d/db-with db [[:db/add -1 :ref+name [[:name "Ivan"] "Petr"]]
+                             [:db/add -1 :age 32]])]
+      (is (= {:age 32} (d/pull db' [:age] 3))))
+    
+    (is (= 1 (:db/id (d/entity db [:name "Ivan"]))))
+    (is (= 3 (:db/id (d/entity db [:ref+name [1 "Petr"]]))))
+    (is (= 3 (:db/id (d/entity db [:ref+name [[:name "Ivan"] "Petr"]]))))))
+
 (deftest test-validation
   (let [db  (d/empty-db {:a+b {:db/tupleAttrs [:a :b]}})
         db1 (d/db-with db [[:db/add 1 :a "a"]])]