implement smart join tree comparator and loop detector

Author: KSDaemon

packages/cubejs-schema-compiler/src/adapter/BaseQuery.js

@@ -441,12 +441,47 @@ export class BaseQuery {
       };
 
       let prevJoins = this.join;
+      let prevJoinMembersJoinHints = joinMembersJoinHints;
       let newJoin = this.joinGraph.buildJoin(constructJH());
 
-      while (newJoin?.joins.length > 0 && !R.equals(prevJoins, newJoin)) {
+      const isOrderPreserved = (base, updated) => {
+        const common = base.filter(value => updated.includes(value));
+        const bFiltered = updated.filter(value => common.includes(value));
+
+        return common.every((x, i) => x === bFiltered[i]);
+      };
+
+      const isJoinTreesEqual = (a, b) => {
+        if (!a || !b || a.root !== b.root || a.joins.length !== b.joins.length) {
+          return false;
+        }
+
+        // We don't care about the order of joins on the same level, so
+        // we can compare them as sets.
+        const aJoinsSet = new Set(a.joins.map(j => `${j.originalFrom}->${j.originalTo}`));
+        const bJoinsSet = new Set(b.joins.map(j => `${j.originalFrom}->${j.originalTo}`));
+
+        if (aJoinsSet.size !== bJoinsSet.size) {
+          return false;
+        }
+
+        for (const val of aJoinsSet) {
+          if (!bJoinsSet.has(val)) {
+            return false;
+          }
+        }
+
+        return true;
+      };
+
+      while (newJoin?.joins.length > 0 && !isJoinTreesEqual(prevJoins, newJoin)) {
         prevJoins = newJoin;
         joinMembersJoinHints = this.collectJoinHintsFromMembers(this.joinMembersFromJoin(newJoin));
+        if (!isOrderPreserved(prevJoinMembersJoinHints, joinMembersJoinHints)) {
+          throw new UserError(`Can not construct joins for the query, potential loop detected: ${prevJoinMembersJoinHints.join('->')} vs ${joinMembersJoinHints.join('->')}`);
+        }
         newJoin = this.joinGraph.buildJoin(constructJH());
+        prevJoinMembersJoinHints = joinMembersJoinHints;
       }
 
       this.collectedJoinHints = R.uniq(constructJH());