UseBinaryAggregateExpression rework

[MaceWindu]

No description provided.

[MaceWindu]

@detoxhby I hope it will solve your issue

[MaceWindu]

Found another issue with this functionality - query cache comparison uses initial expression and still fails

[detoxhby]

Thanks, tested with 7e05a48 ✅

[detoxhby]

Have to correct myself, I forgot that I've removed the LinqToDB.Common.Configuration.Linq.UseBinaryAggregateExpression = true for previous tests and ran without it. Setting it true again fails the same way. ⛔ (tested with 683cedf)

Cannot convert from „System.Linq.Expressions.PropertyExpression” to „System.Linq.Expressions.BinaryExpression” type

lambda_method(Closure , Expression , Object[] )
LinqToDB.Linq.QueryRunner.SetParameters(Query query, IDataContext dataContext, Expression expression, Object[] parameters, Int32 queryNumber) in: C:\dev\ext\linq2db\Source\Linq\QueryRunner.cs, line: 154
LinqToDB.Linq.QueryRunnerBase.SetCommand(Boolean clearQueryHints) in: C:\dev\ext\linq2db\Source\Linq\QueryRunnerBase.cs, line: 74
LinqToDB.Data.DataConnection.QueryRunner.ExecuteReader() in: C:\dev\ext\linq2db\Source\Data\DataConnection.QueryRunner.cs, line: 420
LinqToDB.Linq.QueryRunner.<ExecuteQuery>d__15`1.MoveNext() in: C:\dev\ext\linq2db\Source\Linq\QueryRunner.cs, line: 327
System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)

[MaceWindu]

I have good news.
I've enabled this option for all tests and now it reproduces pretty stable on two tests (TypesTests.Bool1 and Issue271Tests.Test2). This means I can debug and fix it.

[MaceWindu]

@detoxhby could you test it once more?
Update: looks like it is not correct fix as it broke some tests

[detoxhby]

@MaceWindu just did it, something broke. Random errors from not inserting data to even missing FKs :/

(just read your update)

[MaceWindu]

@detoxhby now it should work

[detoxhby]

@MaceWindu seems good! ✅

Even though the commit diff looks terrifying ... was it really "just" that? How was it working for other providers (like SqlServer) and struggle only on SQLCe if there is no provider-specific changes here?
Don't get me wrong, I'm just curious and trying to understand better.

[MaceWindu]

Well, it wasn't SqlCe specific issue. For queries with parameters we generate methods to extract parameter value from expression. They were generated to work with initial expression, but when this optimization applied - expression structure changes and parameter extractor receives expression with different structure and that is why you get all those invalid cast expressions: when method expected element of one type - he received completely different one.

Why it was broken only for SqlCe in your case - I cannot say for sure. It suspect one of those:

• expression wasn't optimized
• optimized expression still had structure, compatible with parameter extraction method

With this fix, expression will be optimized before it used by linq2db for anything else.

Update: also issue with incorrect query caching, fixed with this PR, also was affecting chances to get this error.

[detoxhby]

@MaceWindu thanks for the explanation and fix, keep up the good work!

[sdanyliv]

I think we can use here Count > 3