Translate Math.PI

[Marusyk]

Issue #25049

I've added a new member translator. I expected that it will run after this test

[ConditionalTheory]
[MemberData(nameof(IsAsyncData))]
public virtual Task Where_math_pi(bool async)
{
            return AssertQuery(
                async,
                ss => ss.Set<Product>()
                    .Where(od => Math.Abs(od.ProductID) > Math.PI),
                entryCount: 0);
}

Could you please suggest what I am doing wrong?
It just translates Math.PI to constant without calling my translator. It seems I missed something 🤔

[smitpatel]

Math.PI is a static member access. So the instance is always null hence this check fails.
Correct check (apart from matching member.Name) would be member.DeclaringType == typeof(Math)

[smitpatel]

(also check instance is null)

[Marusyk]

yeah, I will fix that but first I need to run it. To see that the translator at least runs

[smitpatel]

It just translates Math.PI to constant without calling my translator.

You will also need to mark it as non-evaluatable in parameter extraction. https://github.com/dotnet/efcore/blob/main/src/EFCore.SqlServer/Query/Internal/SqlServerEvaluatableExpressionFilter.cs
In this file return false for Math.PI expression (using usual pattern matching)

[Marusyk]

@smitpatel thanks for the advice
The IsEvaluatableExpression catches the following
{[Microsoft.EntityFrameworkCore.Query.QueryRootExpression].Where(od => (3,141592653589793 > Convert(od.ProductID, Double)))}
for test ss => ss.Set<Product>().Where(od => Math.PI > od.ProductID)
Could you please suggest how to return false for Math.PI expression?

[smitpatel]

With that expression tree, we cannot add translation. That expression tree indicates that LINQ compiler inline the constant value when generating expression tree which happens even before the tree reaches EF Core.

cc: @bricelam

[bricelam]

Lame. Probably not worth translating, then.

[smitpatel]

Closing the PR. Will add notes on the issue. @Marusyk - Thanks for investigating this.