fixed issue #8108 (#8111)

CHANGELOG

@@ -1,6 +1,8 @@
 v3.4.3 (XXXX-XX-XX)
 -------------------
 
+* fixed issue #8108: AQL variable - not working query since upgrade to 3.4 release
+
 * fixed possible segfault when using COLLECT with a LIMIT and an offset
 
 * fixed COLLECT forgetting top-level variables after 1000 rows

arangod/Aql/Expression.h

@@ -200,14 +200,14 @@ class Expression {
   }
 
   void clearVariable(Variable const* variable) { _variables.erase(variable); }
+  
+  /// @brief reset internal attributes after variables in the expression were changed
+  void invalidateAfterReplacements();
 
  private:
   /// @brief free the internal data structures
   void freeInternals() noexcept;
 
-  /// @brief reset internal attributes after variables in the expression were changed
-  void invalidateAfterReplacements();
-
   /// @brief find a value in an array
   bool findInArray(AqlValue const&, AqlValue const&, transaction::Methods*,
                    AstNode const*) const;

arangod/Aql/OptimizerRules.cpp

@@ -2386,6 +2386,9 @@ void arangodb::aql::simplifyConditionsRule(Optimizer* opt,
         nn->expression()->replaceNode(simplified);
         modified = true;
       }
+      if (modified) {
+        nn->expression()->invalidateAfterReplacements();
+      }
     }
   }
 

tests/js/server/aql/aql-optimizer-rule-simplify-conditions.js

@@ -152,6 +152,14 @@ function optimizerRuleTestSuite () {
       });
     },
 
+    testIssue8108 : function () {
+      let query = "FOR i IN 1..10 LET x = { y : i } COLLECT z = x.y._id INTO out RETURN 1";
+      let result = AQL_EXECUTE(query).json;
+      // the main thing here is that the query can be executed successfully and 
+      // does not throw a runtime error "variable not found"
+      assertEqual([ 1 ], result);
+    },
+
   };
 }