LINQ Where ignores JsonPropertyNameAttribute when using new for column selection, causing failing ksqldb request.

[mrt181]

Describe the bug When defining a query like this:

    dbContext.CreatePullQuery<SubProperty>()
      .Select(c => new { c.Property })
      .Where(c => c.Property == "test")
      .ToQueryString();

Where SubProperty is defined like this

  [Struct]
  public class SubProperty
  {
    [JsonPropertyName("prop")] public string Property { get; set; } = null!;
  }

The create query string uses the wrong column name Property instead of prop.

To Reproduce Add this unit test to ksqlDb.RestApi.Client.Tests.KSql.Linq.PullQueries.PullQueryExtensionsTests

  [TestCase(Never, ExpectedResult = $"SELECT prop FROM {nameof(SubProperty)}\nWHERE prop == 'test';")]
  [TestCase(Keywords, ExpectedResult = $"SELECT prop FROM {nameof(SubProperty)}\nWHERE prop == 'test';")]
  [TestCase(Always, ExpectedResult = $"SELECT `prop` FROM `{nameof(SubProperty)}`\nWHERE `prop` == 'test';")]
  public string SelectColumnsUsingPullQueryThatHaveJsonPropertyNameAndWhere(IdentifierEscaping escaping)
  {
    //Arrange
    var dbContext = new KSqlDBContext(new KSqlDBContextOptions(TestParameters.KsqlDbUrl)
      { IdentifierEscaping = escaping , ShouldPluralizeFromItemName = false});

    //Act
    var ksql = dbContext.CreatePullQuery<SubProperty>()
      .Select(c => new { c.Property })
      .Where(c => c.Property == "test")
      .ToQueryString();

    //Assert
    return ksql.ReplaceLineEndings();

Expected behavior The returned strings should be:

SELECT prop FROM SubProperty
WHERE prop == 'test';
SELECT prop FROM SubProperty
WHERE prop == 'test';
SELECT `prop` FROM `SubProperty`
WHERE `prop` == 'test';

But instead they are

SELECT prop FROM SubProperty
WHERE Property == 'test';
SELECT prop FROM SubProperty
WHERE Property == 'test';
SELECT `prop` FROM `SubProperty`
WHERE `Property` == 'test';

Environment (please complete the following information):

• ksqlDb version: 7.6.0]
• ksqlDb.RestApi.Client Nuget package version 4.0.0
• TFM net8.0

Additional context For the new expression in the SELECT the attribute information from the property is used (see KSqlVisitor#ProcessVisitNewMember), but in the WHERE expression the Property from the dynamic new type is used which does not have those attributes. The whereClauses need to carry the original members in case a new expression is used and check if those have any relevant attributes.

[tomasfabian]

Hi @mrt181, thank you for the detailed explanation. I have submitted a hot-fix pull request. Could you please review it?

[tomasfabian]

Just for the record, positioning the SELECT clause last facilitates more advanced filtering capabilities. The query provided below functions correctly in the current version 4.0.0:

var ksql = dbContext.CreatePullQuery<SubProperty>()
  .Where(c => c.Property == "test")
  .Select(c => new { c.Property })
  .ToQueryString();

In C# LINQ, it's important to note that the positioning of the FROM, GROUPBY, and SELECT clauses differs from SQL statements.