ConvertTo-Json: Treat large enums as numbers

[jborean93]

PR Summary

Remove special handling from Windows PowerShell that treated enum values backed by Int64 and UInt64 as a string. This ensures that all enum types are serialized as a number and are only treated as a string when -EnumsAsStrings is specified.

As requested this is controlled by the new experimental feature PSSerializeJSONLongEnumAsNumber.

PR Context

When using ConvertTo-Json with an Int64 or UInt64 enum type the value is converted to a string.

enum LongEnum : long {
    LongValue = 1
}

ConvertTo-Json @{key = [LongEnum]::LongValue}

The current behaviour is:

{
    "key": "LongValue"
}

The behaviour after this PR is:

{
    "key": 1
}

Instead this PR removes the extra code that does this as it seems to be from Windows PowerShell days. Even then WinPS can deserialize an Int64 or UInt64 value just fine. This is technically a breaking change but I find the current default is surprising and honestly probably very rare to happen in the real world.

If the user wants to preserve the old behaviour they can set -EnumsAsStrings to have the enum be converted to a string like before.

PR Checklist

• PR has a meaningful title
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• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: or [ WIP ] to the beginning of the title (the WIP bot will keep its status check at Pending while the prefix is present) and remove the prefix when the PR is ready.
• Breaking changes
  • None
  • OR
  • Experimental feature(s) needed
    • Experimental feature name(s): PSSerializeJSONLongEnumAsNumber
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed
    • Issue filed: Document PSSerializeJSONLongEnumAsNumber MicrosoftDocs/PowerShell-Docs#10875
• Testing - New and feature
  • N/A or can only be tested interactively
  • OR
  • Make sure you've added a new test if existing tests do not effectively test the code changed
• Tooling
  • I have considered the user experience from a tooling perspective and don't believe tooling will be impacted.
  • OR
  • I have considered the user experience from a tooling perspective and opened an issue in the relevant tool repository. This may include:
    • Impact on PowerShell Editor Services which is used in the PowerShell extension for VSCode
      (which runs in a different PS Host).
      • Issue filed:
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      • Issue filed:
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      • Issue filed:
    • Impact on EditorSyntax (which provides syntax highlighting with in VSCode, GitHub, and many other editors).
      • Issue filed:

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[iSazonov]

I guess it was a workaround exclusively for JS.
The same case dotnet/aspnetcore#52393

I think we should preserve the workaround.

[jborean93]

I don't see why we should cater to one language when PowerShell is able to deserialize such numbers. The fact that enums already have a workaround with -EnumAsStrings to produce the original output that is done today means people can still get the old behaviour.

Plus that exact scenario in your link serializes just fine with newtonsoft and we don't even do it for non enum long types.

PS /home/jborean> ConvertTo-Json @{foo = ([uint64]'2121241830635120343')}
{
  "foo": 2121241830635120343
}

[iSazonov]

I don't see why we should cater to one language ...

Me too :-) However, a comment in the code points to an internal case. Only MSFT team can find the history and evaluate the relevance of this old workaround.
/cc @StevenBucher98 @SteveL-MSFT

[jborean93]

Just to add more ammunition to the change;

• I’ve never actually seen an enum based on long in the wild before
• We already serialize raw int64 and uint64 values as numbers and not strings so why should these enums be different

[jborean93]

Looks like that ASP issue is specific to ASP, serializing a UInt64 works just fine with both Newtonsoft.Json and System.Text.Json

$sb = [System.Text.StringBuilder]::new()
[Newtonsoft.Json.JsonSerializer]::Create().Serialize([System.IO.StringWriter]::new($sb), @{foo=[uint64]'18446744073709551615'})
$sb.ToString()
# {"foo":18446744073709551615}

[System.Text.Json.JsonSerializer]::Serialize[hashtable](@{foo = [uint64]'18446744073709551615'})
# {"foo":18446744073709551615}

Python is also fine

import json
json.dumps({"foo": 18446744073709551615})
'{"foo": 18446744073709551615}'

[JamesWTruher]

Just to add more ammunition to the change;

* I’ve never actually seen an enum based on long in the wild before

* We already serialize raw int64 and uint64 values as numbers and not strings so why should these enums be different

PowerShell actually as a few enums based on long (or ulong)

[SteveL-MSFT]

The @PowerShell/wg-powershell-cmdlets reviewed this. We believe this is a good change for modern JSON. Although historically, javascript had limits of the precision of large integers due to storing numbers as double precision floats, it seems that NodeJS v10.4.0+ now has a BigInt type and also Jordan's validation that NewtonSoft, System.Text.Json, and Python all handle big ints just fine indicate that this legacy code is no longer valid. We still have a concern about how likely this will break users so we recommend putting this behind an experimental feature to also help advertise this change. We will also recommend adding telemetry to indicate how often users are hitting this code path to ensure we believe this can be non-experimental. This can be added after this PR is merged.

[SteveL-MSFT]

Please put behind an experimental feature

[jborean93]

PowerShell actually as a few enums based on long (or ulong)

There are 1-3 in PowerShell itself (S.M.A/M.M.I) depending on your definitions

[System.AppDomain]::CurrentDomain.GetAssemblies().GetTypes() | Where-Object {
    $_.IsSubclassOf([Enum]) -and
    $_.IsVisible -and
    [Enum]::GetUnderlyingType($_) -in @([int64], [uint64])
} | Select-Object FullName, @{
    N='Assembly'
    E={$_.Assembly.GetName().Name}
}, @{
    N='SubType'
    E={[Enum]::GetUnderlyingType($_).Name}
}

FullName                                                      Assembly                            SubType
--------                                                      --------                            -------
System.Diagnostics.Tracing.EventKeywords                      System.Private.CoreLib              Int64
System.Management.Automation.Tracing.PowerShellTraceKeywords  System.Management.Automation        UInt64
Microsoft.Management.Infrastructure.CimFlags                  Microsoft.Management.Infrastructure Int64
Microsoft.Management.Infrastructure.Options.CimOperationFlags Microsoft.Management.Infrastructure Int64
System.Net.Sockets.IOControlCode                              System.Net.Sockets                  Int64

We still have a concern about how likely this will break users so we recommend putting this behind an experimental feature to also help advertise this change.

I do personally disagree that we really do need to put it behind an experimental feature but I suppose it's a stepping stone to just having it be done by default.

Please put behind an experimental feature

Any docs on what exactly needs to be done for devs on this?

[kilasuit]

@jborean93 the about_experimental_features doc shows what needs to be done to add experimental features in code - hope that helps

[iSazonov]

@SteveL-MSFT Can we merge?