ConfigBuilder.AddJsonFile throws ArgumentOutOfRange if given an empty file

Given the following code:

var config = new ConfigurationBuilder();
var tempFilePath = System.IO.Path.GetTempPath() + Guid.NewGuid().ToString() + ".json" 
var tempFile = File.Create(tempFilePath);
tempFile.Close();
config.AddJsonFile(tempFilePath);

You'll get the following exception:

   at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   at System.Collections.Generic.List`1.get_Item(Int32 index)
   at Microsoft.Extensions.Configuration.Json.JsonConfigurationProvider.Load(Stream stream)
   at Microsoft.Extensions.Configuration.Json.JsonConfigurationProvider.Load()
   at Microsoft.Extensions.Configuration.ConfigurationBuilder.Add(IConfigurationProvider provider)
   at Microsoft.Extensions.Configuration.JsonConfigurationExtensions.AddJsonFile(IConfigurationBuilder configurationBuilder, String path, Boolean optional)
   at Microsoft.Extensions.Configuration.JsonConfigurationExtensions.AddJsonFile(IConfigurationBuilder configurationBuilder, String path)

Now I know that that's probably not the right way to use AddJsonFile but I would have expected a FormatException or something like that.

I'm using 1.0.0-rc2-15822, I attempted to add this as a unit test but I'm having issues with AddJsonFile being in a class that's not referenced by the unit test file I was editing.

[pgrudzien12]

I assume that

configPath = System.IO.Path.GetTempPath() + Guid.NewGuid().ToString() + ".json"

?

@pgrudzien12 Fixed, thanks.

That's what I get for copy-pasting from two different files.

[ses4j]

I get the same error with a configuration file that has only one setting, such as this:

{
    "site": "dev",
}

Note, though, that a second line will workaround the issue.

{
    "site": "dev",
    "whatever": "a second line!"
}

`

[kirthik]

This is happening because if SetBasePath is not called, we assume BasePath to be root of the application. In your case, you will have to do this

var config = new ConfigurationBuilder();
var tempFileName = Guid.NewGuid().ToString() + ".json";
var tempFilePath = System.IO.Path.GetTempPath() + tempFileName;
var tempFile = File.Create(tempFilePath);
tempFile.Close();
config.SetBasePath(System.IO.Path.GetTempPath()).AddJsonFile(tempFileName);

[divega]

It is strange because we use Path.Combine() to concatenate the BasePath and the file name, and that already short-circuits on IsPathRooted() to return just the file name.

[pgrudzien12]

+1
Format exception should be thrown because 'System.ArgumentOutOfRangeException' is misleading if the file is empty.

SetBasePath does not help - file path is constructed fine. At least for RC1

@ses4j first example is corrupted (it has extra comma). Nevertheless in RC1 it loads correctly for me. Could you provide an example of your code that loads configuration and version of dependencies you used?

[divega]

I agreed it would be nice to wrap any of these exception during parsing into a FileFormatException

[divega]

@kirthik can you look into this for rc2?

[pgrudzien12]

I will if you don't mind (both of you).

[divega]

Sure thing! Looking forward to your PR.