From e1e538183ac75bf51cab8ad47616b927fe84b6de Mon Sep 17 00:00:00 2001
From: Shpakh-MSFT <10427420+Shpakh-MSFT@users.noreply.github.com>
Date: Fri, 1 Nov 2024 06:11:10 -0700
Subject: [PATCH] =?UTF-8?q?Added=20new=20method=20on=20IExternalRule=20to?=
 =?UTF-8?q?=20help=20with=20invariantexpression=20ch=E2=80=A6=20(#2725)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

On an effort to remove null rule binding, we need the ability to have an
option to apply null binding before doing the check if binding is null.
This change adds a new method on IExternalRule to help with that.
---
 .../Microsoft.PowerFx.Core/App/Controls/IExternalRule.cs      | 3 +++
 src/libraries/Microsoft.PowerFx.Core/Binding/Binder.cs        | 4 +---
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/libraries/Microsoft.PowerFx.Core/App/Controls/IExternalRule.cs b/src/libraries/Microsoft.PowerFx.Core/App/Controls/IExternalRule.cs
index 408dddfe4..c29990ee9 100644
--- a/src/libraries/Microsoft.PowerFx.Core/App/Controls/IExternalRule.cs
+++ b/src/libraries/Microsoft.PowerFx.Core/App/Controls/IExternalRule.cs
@@ -22,5 +22,8 @@ namespace Microsoft.PowerFx.Core.App.Controls
 
         // Returns true when Binding is non-null, otherwise false.
         bool HasValidBinding { get; }
+
+        // Returns true when rule is constant.
+        bool IsInvariantExpression { get; }
     }
 }
diff --git a/src/libraries/Microsoft.PowerFx.Core/Binding/Binder.cs b/src/libraries/Microsoft.PowerFx.Core/Binding/Binder.cs
index 937173cb3..4dc0fa0e1 100644
--- a/src/libraries/Microsoft.PowerFx.Core/Binding/Binder.cs
+++ b/src/libraries/Microsoft.PowerFx.Core/Binding/Binder.cs
@@ -3619,9 +3619,7 @@ namespace Microsoft.PowerFx.Core.Binding
                     // we need to mark the node as constant, and save the control info so we may look up the
                     // rule later.
                     if (controlInfo?.GetRule(property.InvariantName) is IExternalRule rule &&
-                        rule.HasValidBinding &&
-                        !rule.HasErrorsOrWarnings &&
-                        rule.Binding.IsConstant(rule.Binding.Top))
+                        rule.IsInvariantExpression)
                     {
                         value = controlInfo;
                         isConstant = true;