Bug in Sql.Function Left?

[yarecky1]

Hi,

Just reading the code and found this:

[Sql.Function(                      PreferServerSide = true)]
[Sql.Function(PN.SQLite, "LeftStr", PreferServerSide = true)]
public static string? Left(string? str, int? length)
{
    return length == null || str == null || str.Length < length? null: str.Substring(1, length.Value);
}

Why startIndex = 1 in str.Substring(1, length.Value)?
Shouldn't be there startIndex = 0?
(startIndex = The zero-based starting character position of a substring in this instance.)

[MaceWindu]

Yep, looks like a bug.

[yarecky1]

I'll make PR.

[MaceWindu]

Thanks. Please check if we have test coverage for this function (looks like at least client-side part is missing) and add missing test case.

[yarecky1]

@MaceWindu Where is the best place to insert the tests for functions? I've searched the folders and nothing fits.
I'm asking because I see next bug here (index will be less than 0 and will raise exception):

public static string? Substring(string? str, int? startIndex, int? length)
{
    return str == null || startIndex == null || length == null ? null : str.Substring(startIndex.Value - 1, length.Value);
}

[MaceWindu]

Tests for those functions are there https://github.com/linq2db/linq2db/blob/master/Tests/Linq/Linq/StringFunctionTests.cs
and I don't see them testing non-db execution :-/

[yarecky1]

Ok, already started and decided to add tests to all non-db string functions.

[yarecky1]

Finished.