DapperLib/Dapper

Querying int columns as strings has broken in 2.1.37

sellotape opened this issue · 6 comments

sellotape commented

Might be intentional, but worked in 2.1.35, and I suspect a lot of people will be depending on it and pretty surprised, as there's no mention of a breaking change in the release notes.

To replicate, simply (I'm using Azure SQL Server):

using IDbConnection cx = new SqlConnection("your-connection-string");
string? actual = await cx.QueryFirstOrDefaultAsync<string>("select id from someTableWithAnIntIdColumn").ConfigureAwait(false);

In 2.1.35, this returns e.g. "42". In 2.1.37 it throws System.InvalidCastException : Unable to cast object of type 'System.Int32' to type 'System.String'.

Fuller exception:

System.InvalidCastException : Unable to cast object of type 'System.Int32' to type 'System.String'.
   at Microsoft.Data.SqlClient.SqlDataReader.GetFieldValueFromSqlBufferInternal[T](SqlBuffer data, _SqlMetaData metaData, Boolean isAsync)
   at Microsoft.Data.SqlClient.SqlDataReader.GetFieldValueInternal[T](Int32 i, Boolean isAsync)
   at Microsoft.Data.SqlClient.SqlDataReader.GetFieldValue[T](Int32 i)
   at Dapper.SqlMapper.<>c__DisplayClass209_0`1.<UnderlyingReadViaGetFieldValueFactory>b__0(DbDataReader reader) in /_/Dapper/SqlMapper.cs:line 3134
   at Dapper.SqlMapper.QueryRowAsync[T](IDbConnection cnn, Row row, Type effectiveType, CommandDefinition command) in /_/Dapper/SqlMapper.Async.cs:line 496
   at <my test code>
mgravell commented

That's because we didn't know it was a break. This is related to the GetValue change for strings, to mitigate against a npgsql behaviour.

I've unlisted - will think of best path forward, probably a revert.

  • 👍2
mdx0111 commented

I have the same problem with decimal to string.
Thanks

mgravell commented

Yup, we need to revert a change there (which is why 2.1.37 is hidden); I'll do that now

  • 👍2