Export-Configuration Overwriting Existing Nested Hashtable Values for User

[jkubecki]

Issue description

When using a nested Hashtable with more than 1 value, using Export-Configuration to save the values individually overwrites the previous values for the nested Hashtable.

Sorry if this format is not good for reporting this bug - tried to be as detailed as possible and provide test/example scenario files.

Steps to reproduce the issue

• See the attached Configuration.psd1.txt and Test.ps1.txt files
  • Configuration.psd1.txt
  • Test.ps1.txt
• Place both in the same folder, removing the .txt extensions
• Execute Test.ps1

What's the expected result?

The end of the output to show BOTH values having been overridden in User Configuration file, and Final Config to reflect BOTH overrides:

*** User Configuration File w Foo.Bar AND Foo.Baz overridden

@{
  Foo = @{
    Bar = 42
    Baz = 8675309
  }
}

*** Final Config
{
  "Foo": {
    "Bar": 42,
    "Baz": 8675309
  }
}

What's the actual result?

The end of the output shows only the MOST RECENT value having been overridden in User Configuration file, and Final Config only reflects the MOST RECENT override:

*** User Configuration File w Foo.Bar AND Foo.Baz overridden

@{
  Foo = @{
    Baz = 8675309
  }
}

*** Final Config
{
  "Foo": {
    "Bar": 1,
    "Baz": 8675309
  }
}

[Jaykul]

I'm not sure that I follow what you expected to happen, but perhaps I need to document this better.

The Export command follows PowerShell's usual semantics for export: it takes an input object and exports that entire object, overwriting any previous content in the destination. It is not an Update and that is why there is an Update-Metadata and Update-Object.

Essentially, Import-Configuration and Export-Configuration always work with the full Configuration object, and the Export command is not designed to allow you to export a subset, nor only the values the user has changed.

If you want to update a single value, you should either:

1. Import-Metadata and add or set the value, then Export-Metadata
2. Use Update-Metadata (note: this currently can't add values)