DapperLib / DapperLib/Dapper

Missing implicit numeric cast of decimal to integer in C# record

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Dominant language
C#
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Description

Hi, I've found that Dapper behaves differently when using plain classes or records (working on Oracle 12).

When getting results from a command, like

return await connection.QueryAsync<SomeObject>(query);

this

public class SomeObject
{
    public int Id { get; set; }
}

works fine while this

public record SomeObject(int Id)

throws

System.InvalidOperationException: A parameterless default constructor or one matching signature (System.Decimal ID) is required for SomeNamespace.SomeObjectmaterialization

If I change property data type, like this

public record SomeObject(decimal Id)

it works, but I don't want to use decimal instead of int.

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First steps

  1. Read the whole issue, then the project's contributing guide.
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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the QueryAsync reproduction in the issue and compare materialization of the class and positional record when the result value is System.Decimal. Done means a record with an int Id can be materialized from that result, while the existing class behavior remains intact.

Written by the indexing model from the issue text.

Assessment

Tech stack
csharp
Domain
backend, databases
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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