HasQueryFilter does not compile expression correctly in some cases

[hikalkan]

Hi,

I'm having a strange problem with new global query filters (HasQueryFilter). My code is complicated since I'm developing an application framework. So, I will share the related code.

1. Using HasQueryFilter like that:

modelBuilder.Entity<TEntity>().HasQueryFilter(CreateFilterExpression<TEntity>());

2. CreateFilterExpression is defined as below:

protected virtual Expression<Func<TEntity, bool>> CreateFilterExpression<TEntity>() where TEntity : class
{
    Expression<Func<TEntity, bool>> expression = PredicateBuilder.True<TEntity>();

    if (typeof(ISoftDelete).IsAssignableFrom(typeof(TEntity)))
    {
        expression = expression.And(e => !IsSoftDeleteFilterEnabled || !((ISoftDelete) e).IsDeleted);
    }

    if (typeof(IMayHaveTenant).IsAssignableFrom(typeof(TEntity)))
    {
        expression = expression.And(e => !IsMayHaveTenantFilterEnabled || ((IMayHaveTenant)e).TenantId == CurrentTenantId);
    }

    if (typeof(IMustHaveTenant).IsAssignableFrom(typeof(TEntity)))
    {
        expression = expression.And(e => !IsMustHaveTenantFilterEnabled || (CurrentTenantId == null || ((IMustHaveTenant)e).TenantId == CurrentTenantId));
    }

    return expression;
}

What I'm achiving here to combine soft delete and multitenant filters based on implemented interfaces of entities, as can be understood easily.

I'm using this PredicateBuilder (http://www.albahari.com/nutshell/predicatebuilder.aspx) to create the expression.

IsSoftDeleteFilterEnabled, IsMayHaveTenantFilterEnabled, CurrentTenantId... are properties of my dbcontext.

Problem

The problem is !IsSoftEnabled (and other boolean flags) is not properly working. It caches the first dbcontext instance and never called again for later dbcontext instances. But CurrentTenantId property is properly called (there is interesting thing here: It's called one more time for each different query, before the actual query - I suppose it's for caching the query, but no problem).

The interesting this is that, when I compare IsSoftEnabled value with a property of the entity, it starts working. I suppose when we compare it via an entity property (like IsSoftDeleteFilterEnabled == e.IsDeleted || !((ISoftDelete) e).IsDeleted - this is just a stupid example) it does not grab value, but gets the expression property.

For this reason, I can not properly create a boolean flag to disable/enable a filter individually.

[hikalkan]

Additional information:

This does not work (as I said above):

e => !IsSoftDeleteFilterEnabled || !((ISoftDelete) e).IsDeleted

IsSoftDeleteFilterEnabled is only called one time, not for all queries. It somehow caches the value (or dbcontext instance)

But this works:

e => !((ISoftDelete) e).IsDeleted || ((ISoftDelete)e).IsDeleted != IsSoftDeleteFilterEnabled

By the magic of logical expressions, both expressions are actually identical (you can proove it) and I'm using this workaround. However I'm not sure the second one produce good & optimum SQL.

[anpete]

@smitpatel This look like a dupe of #9825?