Binding NpgsqlConnectionStringBuilder to configuration does not work on .net 7.0

[frabe1579]

Description

I'm used to bind an instance of NpgsqlConnectionStringBuilder (from Npgsql) to the configuration during startup, but this does not work anymore after upgrading to .net 7.0: The instance remains empty and values are not loaded from configuration

Reproduction Steps

• Create a Console Project like this:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net7.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.Extensions.Configuration" Version="7.0.0" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="7.0.0" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="7.0.0" />
    <PackageReference Include="Npgsql" Version="7.0.0" />
  </ItemGroup>

  <ItemGroup>
    <None Update="appsettings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
  </ItemGroup>

</Project>

• Add this to Program.cs:

using System.Diagnostics;
using Microsoft.Extensions.Configuration;
using Npgsql;

var configuration = new ConfigurationBuilder()
  .AddJsonFile("appsettings.json")
  .Build();

Debug.Assert(configuration["db:host"] == "localhost");

var csb = new NpgsqlConnectionStringBuilder();
configuration.GetSection("db").Bind(csb);
var cs = csb.ToString();

Debug.Assert(csb.Host != null);
Console.WriteLine("Host is: " + csb.Host);

Add appsettings.json file with this content:

{
  "db": {
    "host": "localhost"
  }
}

If you dotnet run, the program crashes due to the last assertion: the values are not loaded from configuration.
If the project is downgraded to .net6.0 (and also the deps), the program runs ok, the values are correctly loaded.
I think it's not a direct problem of Npgsql, but something related to a change in .net7 that is not compatible with internal mappings used by NpgsqlConnectionStringBuilder.
A direct binding to a POCO runs like a charm, but with NpgsqlConnectionStringBuilder no.

Expected behavior

The configuration data is loaded and mapped to the instance passed to Bind.

Actual behavior

The configuration data is not loaded and the instance passed to Bind reamins empty.

Regression?

Yes, this worked on .net 6.0, at least up to 6.0.10.

Known Workarounds

No direct workaraoud, it's necessary to use a POCO to bind from configuration.

Configuration

.NET 7.0
Window 11 Pro x64

Other information

The problem might be in changes to configuration binder, considering that NpgsqlConnectionStringBuilder exposes properties but also a IDictionary<string, object?>.

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Issue Details

---

Description

I'm used to bind an instance of NpgsqlConnectionStringBuilder (from Npgsql) to the configuration during startup, but this does not work anymore after upgrading to .net 7.0: The instance remains empty and values are not loaded from configuration

Reproduction Steps

• Create a Console Project like this:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net7.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.Extensions.Configuration" Version="7.0.0" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="7.0.0" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="7.0.0" />
    <PackageReference Include="Npgsql" Version="7.0.0" />
  </ItemGroup>

  <ItemGroup>
    <None Update="appsettings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
  </ItemGroup>

</Project>

• Add this to Program.cs:

using System.Diagnostics;
using Microsoft.Extensions.Configuration;
using Npgsql;

var configuration = new ConfigurationBuilder()
  .AddJsonFile("appsettings.json")
  .Build();

Debug.Assert(configuration["db:host"] == "localhost");

var csb = new NpgsqlConnectionStringBuilder();
configuration.GetSection("db").Bind(csb);
var cs = csb.ToString();

Debug.Assert(csb.Host != null);
Console.WriteLine("Host is: " + csb.Host);

Add appsettings.json file with this content:

{
  "db": {
    "host": "localhost"
  }
}

If you dotnet run, the program crashes due to the last assertion: the values are not loaded from configuration.
If the project is downgraded to .net6.0 (and also the deps), the program runs ok, the values are correctly loaded.
I think it's not a direct problem of Npgsql, but something related to a change in .net7 that is not compatible with internal mappings used by NpgsqlConnectionStringBuilder.
A direct binding to a POCO runs like a charm, but with NpgsqlConnectionStringBuilder no.

Expected behavior

The configuration data is loaded and mapped to the instance passed to Bind.

Actual behavior

The configuration data is not loaded and the instance passed to Bind reamins empty.

Regression?

Yes, this worked on .net 6.0, at least up to 6.0.10.

Known Workarounds

No direct workaraoud, it's necessary to use a POCO to bind from configuration.

Configuration

.NET 7.0
Window 11 Pro x64

Other information

The problem might be in changes to configuration binder, considering that NpgsqlConnectionStringBuilder exposes properties but also a IDictionary<string, object?>.

Author:	frabe1579
Assignees:	-
Labels:	untriaged, area-Extensions-Configuration
Milestone:	-

[tarekgh]

This is fixed and should be released in the next service release of .NET 7.0.

#78118

If you are interested to try the fix from now, you may add the following nuget feed

    <add key="dotnet8" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet8/nuget/v3/index.json" />

and the use package version like 8.0.0-alpha.1.22578.1.

[frabe1579]

I can confirm, with 8.0.0-alpha.1.22578.1 the problem is solved.