Description
Configuration Json provider loads null values as empty string.
I understand that other providers like the environment variables one do not support to add null, however I don't think this should prevent the json provider to do the expected thing of preserving null.
Also as the enviornment variables provider supports adding both a value and children for a key which the json one doesn't so I don't think that a limitation of one provider should affect the others.
One important consideration is that changing this will mean that null values will return false for Exists(), as the Exists() method is a misnomer, as the outcome is "not empty", while currently given null is converted to empty string, Exists() is returning true.
/// <summary>
/// Determines whether the section has a <see cref="IConfigurationSection.Value"/> or has children
/// </summary>
public static bool Exists(this IConfigurationSection section);
Repro
config.json
Program.cs
using System;
using Microsoft.Extensions.Configuration;
namespace Sample
{
class Program
{
static void Main(string[] args)
{
var config = new ConfigurationBuilder()
.AddJsonFile("config.json")
.Build();
Console.WriteLine("{");
Console.WriteLine("\t" + GetString(config.GetSection("g"));
Console.WriteLine("}");
}
private static string GetString(IConfigurationSection configurationSection) => GetString(configurationSection.Key, configurationSection.Value);
private static string GetString(string key, string value) => $"\"{key}\":" + (value is null ? "null" : $"\"{value}\"");
}
}Sample.csproj
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net5.0</TargetFramework>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="5.0.0-preview.7.20364.11" />
</ItemGroup>
<ItemGroup>
<Content Include="config.json">
<CopyToOutputDirectory>Always</CopyToOutputDirectory>
</Content>
</ItemGroup>
</Project>
Expected output
Actual output
Description
Configuration Json provider loads null values as empty string.
I understand that other providers like the environment variables one do not support to add null, however I don't think this should prevent the json provider to do the expected thing of preserving null.
Also as the enviornment variables provider supports adding both a value and children for a key which the json one doesn't so I don't think that a limitation of one provider should affect the others.
One important consideration is that changing this will mean that null values will return
falseforExists(), as theExists()method is a misnomer, as the outcome is "not empty", while currently givennullis converted to empty string,Exists()is returningtrue.Repro
config.json
{ "g": null, }Program.cs
Sample.csproj
Expected output
{ "g": null }Actual output
{ "g": "" }