Regression in 6.0.0: Dictionary<string, object> keys no longer resolved in RuleExpressionParser expressions

[florianwakam]

Description

RulesEngine version: 6.0.0 (regression from 5.0.3)

When evaluating expressions via RuleExpressionParser.Evaluate<bool>() with a RuleParameter wrapping a Dictionary<string, object>, dictionary keys are no longer resolved as named properties in the expression. Instead, the key name appears to be treated as a string literal, making the evaluation always return a fixed value regardless of the dictionary contents.

Root Cause

The underlying System.Linq.Dynamic.Core was upgraded from 1.3.7 (v5.0.3) to 1.6.0.1 (v6.0.0). This upgrade introduced a breaking change in how dictionary keys are resolved when used as a RuleParameter.

Minimal Reproduction

var parser = new RuleExpressionParser(new ReSettings());

var payload = new Dictionary<string, object>
{
    { "Formule", "Essentielle" }
};

var ruleParameters = new[] { RuleParameter.Create("_", payload) };

// In v5.0.3: correctly returns false ("Essentielle" != "Essentielle" => false)
// In v6.0.0: always returns true, ignores dictionary value
bool result = parser.Evaluate<bool>("Formule!=""Essentielle""", ruleParameters);

Console.WriteLine(result); // Expected: false — Actual: true

Observed Behavior (v6.0.0)

The expression Formule!="Essentielle" with payload { "Formule": "Essentielle" } returns true instead of false. The dictionary value is completely ignored — the expression appears to compare the string literal "Formule" against "Essentielle", which always evaluates to true for != regardless of what is in the dictionary.

Symmetrically, Formule="Essentielle" always returns false.

Expected Behavior (v5.0.3)

The dictionary key "Formule" is resolved to its value "Essentielle", so:

• Formule!="Essentielle" → false ✅
• Formule="Essentielle" → true ✅

Impact

This is a silent regression: no exception is thrown, evaluations simply always return a constant value regardless of the input dictionary. Any conditional rule that relies on a Dictionary<string, object> payload is silently broken after upgrading to 6.0.0.

Workaround

Reverting to RulesEngine 5.0.3 restores correct behavior. We have not yet found a configuration or API change in 6.0.0 that fixes this while staying on 6.0.0.

Environment

• .NET 10
• RulesEngine 6.0.0 (broken) / 5.0.3 (working)