SQLite: Issues around support for unsigned long

[roji]

While working on JSON partial updates for ExecuteUpdate (#28766), I ran into some issues with corruption of ulong values - see code sample below. Although the below sample is JSON-specific (and maybe even specific to json_set), I suspect SQLite doesn't actually fully support ulong, and we maybe shouldn't have supported this in M.D.SQLite.

For now, I'll throw for ExecuteUpdate partial updates on ulong properties inside JSON.

using var connection = new SqliteConnection("Data Source=:memory:");
connection.Open();

using var command = connection.CreateCommand();
command.CommandText = """
CREATE TABLE foo (json TEXT);
INSERT INTO foo (json) VALUES ('{ "a": 8 }');
""";
command.ExecuteNonQuery();

// command.CommandText = """UPDATE foo SET json = json_set(json, '$.a', @p)""";
// command.Parameters.Add(new SqliteParameter("p", DbType.UInt64) { Value = ulong.MaxValue - 1 });
command.CommandText = """UPDATE foo SET json = json_set(json, '$.a', 18446744073709551615)""";

command.ExecuteNonQuery();

command.CommandText = "SELECT json FROM foo";
var json = (string)command.ExecuteScalar()!;

Console.WriteLine(json); // {"a":-2} when using a parameter, {"a":1.84467440737096e+19} when using a literal.

var reader = new Utf8JsonReader(Encoding.UTF8.GetBytes(json));
reader.Read();
reader.Read();
reader.Read();
var x = reader.GetUInt64(); // FormatException: Either the JSON value is not in a supported format, or is out of bounds for a UInt64

/cc @cincuranet, @AndriySvyryd (this probably also affects the update pipeline)

[cincuranet]

As the documentation says: UInt64: Large values overflow. Int64 is fine.

I'm not sure we can do better here.

[roji]

OK, good that it's documented... And yeah, I agree there's probably not much we can do. I'd argue that if large values overflow, maybe ulong shouldn't be "supported" at all (given that it doesn't support half of the range, which is the main reason one would use ulong rather than long...). In other words, maybe let's bring up the question of removing support for it (breaking change)?