suggested fix for issue #384 (#386)

* fix for ruleparameter name changes against cached rules

* fixed indentation to match rest of code

* suggested change implemented

src/RulesEngine/RulesEngine.cs

@@ -101,7 +101,9 @@ namespace RulesEngine
         /// <returns>List of rule results</returns>
         public async ValueTask<List<RuleResultTree>> ExecuteAllRulesAsync(string workflowName, params RuleParameter[] ruleParams)
         {
-            var ruleResultList = ValidateWorkflowAndExecuteRule(workflowName, ruleParams);
+            var sortedRuleParams = ruleParams.ToList();
+            sortedRuleParams.Sort((RuleParameter a, RuleParameter b) => string.Compare(a.Name, b.Name));
+            var ruleResultList = ValidateWorkflowAndExecuteRule(workflowName, sortedRuleParams.ToArray());
             await ExecuteActionAsync(ruleResultList);
             return ruleResultList;
         }
@@ -343,7 +345,8 @@ namespace RulesEngine
 
         private string GetCompiledRulesKey(string workflowName, RuleParameter[] ruleParams)
         {
-            var key = $"{workflowName}-" + string.Join("-", ruleParams.Select(c => c.Type.Name));
+            var ruleParamsHash = string.Join("-", ruleParams.Select(c => $"{c.Name}_{c.Type.Name}")).GetHashCode();
+            var key = $"{workflowName}-" + ruleParamsHash;
             return key;
         }
 

test/RulesEngine.UnitTest/ParameterNameChangeTest.cs

@@ -0,0 +1,45 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using RulesEngine.Models;
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Dynamic;
+using System.Linq;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace RulesEngine.UnitTest
+{
+    [ExcludeFromCodeCoverage]
+    public class ParameterNameChangeTest
+    {
+        [Fact]
+        public async Task RunTwiceTest_ReturnsExpectedResults()
+        {
+            var workflow = new Workflow {
+                WorkflowName = "ParameterNameChangeWorkflow",
+                Rules = new Rule[] {
+                    new Rule {
+                        RuleName = "ParameterNameChangeRule",
+                        RuleExpressionType = RuleExpressionType.LambdaExpression,
+                        Expression = "test.blah == 1"
+                    }
+                }
+            };
+            var engine = new RulesEngine();
+            engine.AddOrUpdateWorkflow(workflow);
+
+            dynamic dynamicBlah = new ExpandoObject();
+            dynamicBlah.blah = (Int64)1;
+            var input_pass = new RuleParameter("test", dynamicBlah);
+            var input_fail = new RuleParameter("SOME_OTHER_NAME", dynamicBlah);
+            // RuleParameter name matches expression, so should pass.
+            var pass_results = await engine.ExecuteAllRulesAsync("ParameterNameChangeWorkflow", input_pass);
+            // RuleParameter name DOES NOT MATCH expression, so should fail.
+            var fail_results = await engine.ExecuteAllRulesAsync("ParameterNameChangeWorkflow", input_fail);
+            Assert.True(pass_results.First().IsSuccess);
+            Assert.False(fail_results.First().IsSuccess);
+        }
+    }
+}