EnableExceptionAsErrorMessage = false does not actually throw exception, but ignores/supresses it

[rklec]

STR

Have any invalid rule or one that somehow else throws an exception.

And have the settings configured as such:

      var engineSettings = new ReSettings()
        {
            CustomActions = // ...
            CustomTypes = // ...
            EnableExceptionAsErrorMessage = false
        };
     
        new RulesEngine.RulesEngine(mailWorkflows, engineSettings);     

What should happen

EnableExceptionAsErrorMessage = false is explained on https://microsoft.github.io/RulesEngine/#settings should do the following:

Otherwise [= if false], throws an exception. This setting is only applicable if IgnoreException is set to false.

Notably IgnoreException is not touched, i.e. it is (as per https://microsoft.github.io/RulesEngine/#settings aka the default set to false)

What happens

Errors are silently ignored.

More information

I have also indicated this in https://github.com/microsoft/RulesEngine/issues/623, see this for a practical example.

System

    <TargetFramework>net8.0</TargetFramework>
<!-- ... -->
    <PackageReference Include="RulesEngine" Version="5.0.3" /> 

aka .NET 8

Windows 10

[rklec]

Okay tried it with a simple ruie with wrong Success name, ...

       "OnSuccess": {
          "Name": "EvaluateRuleX",
          "Context": {
          }
        },

and when debugging (catching all CLR exceptions), I e.g. land here: https://github.com/microsoft/RulesEngine/blob/dc5298989583954cd6aac598267747b4ce635f45/src/RulesEngine/Actions/ActionBase.cs#L22

It handles the exception and returns it.

At least for such "system exceptions". it's quite obvious there that these are ignored?

[rklec]

I also reproduced this in your DemoApp -this time using an obvious syntax error in an expression that results in an

index 88f9ad9..54e5c95 100644
--- a/demo/DemoApp/JSONDemo.cs
+++ b/demo/DemoApp/JSONDemo.cs
@@ -41,7 +41,10 @@ namespace DemoApp
             var fileData = File.ReadAllText(files[0]);
             var workflow = JsonConvert.DeserializeObject<List<Workflow>>(fileData);

-            var bre = new RulesEngine.RulesEngine(workflow.ToArray(), null);
+            var bre = new RulesEngine.RulesEngine(workflow.ToArray(), new ReSettings() {
+                EnableExceptionAsErrorMessage = false,
+                IgnoreException = false
+            });

             string discountOffered = "No discount offered.";

diff --git a/demo/DemoApp/Workflows/Discount.json b/demo/DemoApp/Workflows/Discount.json
index ad556d9..eb3b156 100644
--- a/demo/DemoApp/Workflows/Discount.json
+++ b/demo/DemoApp/Workflows/Discount.json
@@ -8,7 +8,7 @@
         "ErrorMessage": "One or more adjust rules failed.",
         "ErrorType": "Error",
         "RuleExpressionType": "LambdaExpression",
-        "Expression": "input1.country == \"india\" AND input1.loyaltyFactor <= 2 AND input1.totalPurchasesToDate >= 5000 AND input2.totalOrders > 2 AND input3.noOfVisitsPerMonth > 2"
+        "Expression": "input1.countr == \"india\" AND input1.loyaltyFactor <= 2 AND input1.totalPurchasesToDate >= 5000 AND input2.totalOrders > 2 AND input3.noOfVisitsPerMonth > 2"
       },
       {
         "RuleName": "GiveDiscount20",      

Ah okay, if I change it to input1X.countr this correctly throws though:

Unhandled exception. RulesEngine.Exceptions.RuleException: Error while compiling rule GiveDiscount10: Unknown identifier 'input1X' ---> Unknown identifier 'input1X' (at index 0)

Maybe it only affects ActionWorkflows though, where you have no example for in the demo apps as far as I see?

[rklec]

Also asked a related question about this, because it totally confuses me how many places there are to store some exceptions (or exception messages): https://github.com/microsoft/RulesEngine/discussions/628