Fix for #294 (#297)

* only test

* fix

* xx

* xx

Author: david-garcia-garcia

src/System.Linq.Dynamic.Core/DynamicExpressionParser.cs

@@ -68,7 +68,7 @@ public static LambdaExpression ParseLambda([CanBeNull] ParsingConfig parsingConf
 
             if (parsingConfig != null && parsingConfig.RenameParameterExpression && parameters.Length == 1)
             {
-                var renamer = new ParameterExpressionRenamer(parser.ItName);
+                var renamer = new ParameterExpressionRenamer(parser.LastLambdaItName);
                 parsedExpression = renamer.Rename(parsedExpression, out ParameterExpression newParameterExpression);
 
                 return Expression.Lambda(parsedExpression, new[] { newParameterExpression });

src/System.Linq.Dynamic.Core/Parser/ExpressionParser.cs

@@ -46,6 +46,15 @@ public class ExpressionParser
         /// </summary>
         public string ItName { get; private set; } = KeywordsHelper.KEYWORD_IT;
 
+        /// <summary>
+        /// There was a problem when an expression contained multiple lambdas where
+        /// the ItName was not cleared and freed for the next lambda. This variable
+        /// store the ItName of the last parsed lambda. Not used internally by
+        /// ExpressionParser, but used to preserve compatiblity of parsingConfig.RenameParameterExpression
+        /// which was designed to wonly work with mono-lambda expressions
+        /// </summary>
+        public string LastLambdaItName { get; private set; } = KeywordsHelper.KEYWORD_IT;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="ExpressionParser"/> class.
         /// </summary>
@@ -1669,6 +1678,7 @@ Expression ParseMemberAccess(Type type, Expression instance)
             {
                 // This might be an internal variable for use within a lambda expression, so store it as such
                 _internals.Add(id, _it);
+                string _previousItName = ItName;
 
                 // Also store ItName (only once)
                 if (string.Equals(ItName, KeywordsHelper.KEYWORD_IT))
@@ -1679,7 +1689,14 @@ Expression ParseMemberAccess(Type type, Expression instance)
                 // next
                 _textParser.NextToken();
 
-                return ParseConditionalOperator();
+                LastLambdaItName = ItName;
+                var exp = ParseConditionalOperator();
+
+                // Restore previous context and clear internals
+                _internals.Remove(id);
+                ItName = _previousItName;
+
+                return exp;
             }
 
             throw ParseError(errorPos, Res.UnknownPropertyOrField, id, TypeHelper.GetTypeName(type));

test/System.Linq.Dynamic.Core.Tests/DynamicExpressionParserTests.cs

@@ -1,10 +1,10 @@
-using System.Collections.Generic;
+using NFluent;
+using System.Collections.Generic;
 using System.Linq.Dynamic.Core.CustomTypeProviders;
 using System.Linq.Dynamic.Core.Exceptions;
 using System.Linq.Dynamic.Core.Tests.Helpers.Models;
 using System.Linq.Expressions;
 using System.Reflection;
-using NFluent;
 using Xunit;
 using User = System.Linq.Dynamic.Core.Tests.Helpers.Models.User;
 
@@ -256,7 +256,7 @@ public void DynamicExpressionParser_ParseLambda_WithStructWithEquality(string qu
             var qry = testList.AsQueryable();
 
             // Act
-            ulong expectedX = (ulong) long.MaxValue + 3;
+            ulong expectedX = (ulong)long.MaxValue + 3;
 
             query = string.Format(query, expectedX);
             LambdaExpression expression = DynamicExpressionParser.ParseLambda(qry.GetType(), null, query);
@@ -613,6 +613,40 @@ public void DynamicExpressionParser_ParseLambda_StringLiteralEmbeddedQuote_Retur
             Assert.Equal(expectedRightValue, rightValue);
         }
 
+        /// <summary>
+        /// @see https://github.com/StefH/System.Linq.Dynamic.Core/issues/294
+        /// </summary>
+        [Fact]
+        public void DynamicExpressionParser_ParseLambda_MultipleLambdas()
+        {
+            var users = new[]
+            {
+                new { name = "Juan", age = 25 },
+                new { name = "Juan", age = 25 },
+                new { name = "David", age = 12 },
+                new { name = "Juan", age = 25 },
+                new { name = "Juan", age = 4 },
+                new { name = "Pedro", age = 2 },
+                new { name = "Juan", age = 25 }
+            }.ToList();
+
+            IQueryable query;
+
+            // One lambda
+            string res1 = "[{\"Key\":{\"name\":\"Juan\"},\"nativeAggregates\":{\"ageSum\":104},\"Grouping\":[{\"name\":\"Juan\",\"age\":25},{\"name\":\"Juan\",\"age\":25},{\"name\":\"Juan\",\"age\":25},{\"name\":\"Juan\",\"age\":4},{\"name\":\"Juan\",\"age\":25}]},{\"Key\":{\"name\":\"David\"},\"nativeAggregates\":{\"ageSum\":12},\"Grouping\":[{\"name\":\"David\",\"age\":12}]},{\"Key\":{\"name\":\"Pedro\"},\"nativeAggregates\":{\"ageSum\":2},\"Grouping\":[{\"name\":\"Pedro\",\"age\":2}]}]";
+            query = users.AsQueryable();
+            query = query.GroupBy("new(name as name)", "it");
+            query = query.Select("new (it.Key as Key, new(it.Sum(x => x.age) as ageSum) as nativeAggregates, it as Grouping)");
+            Assert.Equal(res1, Newtonsoft.Json.JsonConvert.SerializeObject(query));
+
+            // Multiple lambdas
+            string res2 = "[{\"Key\":{\"name\":\"Juan\"},\"nativeAggregates\":{\"ageSum\":0,\"ageSum2\":104},\"Grouping\":[{\"name\":\"Juan\",\"age\":25},{\"name\":\"Juan\",\"age\":25},{\"name\":\"Juan\",\"age\":25},{\"name\":\"Juan\",\"age\":4},{\"name\":\"Juan\",\"age\":25}]},{\"Key\":{\"name\":\"David\"},\"nativeAggregates\":{\"ageSum\":0,\"ageSum2\":12},\"Grouping\":[{\"name\":\"David\",\"age\":12}]},{\"Key\":{\"name\":\"Pedro\"},\"nativeAggregates\":{\"ageSum\":0,\"ageSum2\":2},\"Grouping\":[{\"name\":\"Pedro\",\"age\":2}]}]";
+            query = users.AsQueryable();
+            query = query.GroupBy("new(name as name)", "it");
+            query = query.Select("new (it.Key as Key, new(it.Sum(x => x.age > 25 ? 1 : 0) as ageSum, it.Sum(x => x.age) as ageSum2) as nativeAggregates, it as Grouping)");
+            Assert.Equal(res2, Newtonsoft.Json.JsonConvert.SerializeObject(query));
+        }
+
         [Fact]
         public void DynamicExpressionParser_ParseLambda_StringLiteralStartEmbeddedQuote_ReturnsBooleanLambdaExpression()
         {