Add VssClientCredentials support to Get-TfsClientCredentials for ClientOM 19+

[Copilot]

Get-TfsClientCredentials fails on ClientOM 19/20 because Microsoft.TeamFoundation.Client.TfsClientCredentials was removed. The replacement is Microsoft.VisualStudio.Services.Client.VssClientCredentials.

Changes

• New credential path for ClientOM 19+: Check for VssClientCredentials availability and use it with VssOAuthAccessTokenCredential or VssOAuthCredential
• Backwards compatibility: Fall back to TfsClientCredentials for older SDK versions
• Verbose logging: Log when VssClientCredentials is present but OAuth credential types are missing

# For ClientOM 19+, now returns VssClientCredentials
# For older SDKs, still returns TfsClientCredentials
$credentials = Get-VstsTfsClientCredentials -OMDirectory $omDir

The pattern mirrors the existing Get-VssCredentials implementation for type detection and fallback handling.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• 03nvsblobprodwcus014.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 055vsblobprodwcus02.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 1g1vsblobprodwcus01.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 3eavsblobprodwcus03.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 3zgvsblobprodwcus024.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 40qvsblobprodwcus022.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 4fdvsblobprodwcus012.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 5tbvsblobprodwcus06.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 61cvsblobprodwcus010.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 73dvsblobprodwcus07.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 8usvsblobprodwcus011.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• 9owvsblobprodwcus020.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• arpvsblobprodwcus017.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• crcvsblobprodwcus021.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• fslvsblobprodwcus015.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• grnvsblobprodwcus04.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• k92vsblobprodwcus08.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• mnzvsblobprodwcus05.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• pl8vsblobprodwcus09.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• uubvsblobprodwcus018.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• vwmvsblobprodwcus016.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• x4wvsblobprodwcus013.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• xg1vsblobprodwcus019.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)
• xlkvsblobprodwcus023.vsblob.vsassets.io
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Latest PowerShell task SDK is incompatible with ClientOM 19 and 20</issue_title>
<issue_description>This causes the following function:

Get-TfsClientCredentials

to fail, because the class Microsoft.TeamFoundation.Client.TfsClientCredentials no longer exists.

This has been replaced by Microsoft.VisualStudio.Services.Client.VssClientCredentials from assembly: Microsoft.VisualStudio.Services.Client.Interactive.

The Get-TfsClientCredentials should probably test for the existence of the VssClientCredentials and use that, then fall back to TfsClientCredentials for backwards compat.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Latest PowerShell task SDK is incompatible with ClientOM 19 and 20 #1135

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