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Fixes #11966 - Add notes about CIM/CDXML bugs with PipelineVariable #12026

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Apr 24, 2025
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Fixes #11966 - Add notes about CIM/CDXML bugs with PipelineVariable #12026

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60 changes: 59 additions & 1 deletion reference/5.1/Microsoft.PowerShell.Core/About/about_CommonParameters.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
---
description: Describes the parameters that can be used with any cmdlet.
Locale: en-US
ms.date: 07/02/2024
ms.date: 04/24/2025
no-loc: [Debug, Verbose, Confirm]
online version: https://learn.microsoft.com/powershell/module/microsoft.powershell.core/about/about_commonparameters?view=powershell-5.1&WT.mc_id=ps-gethelp
schema: 2.0.0
Expand Down Expand Up @@ -471,6 +471,64 @@ At line:1 char:1
+ FullyQualifiedErrorId : VariableNotFound,Microsoft.PowerShell.Commands.GetVariableCommand
```

> [!CAUTION]
> There are two known issues with using the **PipelineVariable** parameter in a
> pipeline that includes CimCmdlets or CDXML cmdlets. In the following
> examples, `Get-Partition` is a CDXML function and `Get-CimInstance` is a
> CimCmdlet.

1. CDXML functions use `[CmdletBinding()]`, which allows the
**PipelineVariable** parameter.

```powershell
Get-Partition -pv pvar
```

However, when you use **PipelineVariable** in Windows PowerShell v5.1, you
receive the following error.

```Output
Get-Partition : Cannot retrieve the dynamic parameters for the cmdlet.
Object reference not set to an instance of an object.

At line:1 char:1
+ get-partition -PipelineVariable pvar
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [Get-Partition], ParameterBindingException
+ FullyQualifiedErrorId : GetDynamicParametersException,Get-Partition
```

1. When the preceding command is _not_ a CDXML command and the downstream
contains either command type, the **PipelineVariable** remains as the last
accumulated object.

```powershell
Get-CimInstance Win32_DiskDrive -pv pvar |
ForEach-Object {
Write-Host "Before: $($pvar.Index)"
[pscustomobject]@{ DiskNumber = $_.Index }
} |
Get-Partition |
ForEach-Object {
Write-Host "After: $($pvar.Index)"
}
```

Notice that the value of `$pvar` set to the last object in the pipeline for
the second `ForEach-Object` command.

```Output
Before: 1
Before: 2
Before: 0
After: 0
After: 0
After: 0
After: 0
After: 0
After: 0
```

### -ProgressAction

Determines how PowerShell responds to progress updates generated by a script,
Expand Down
73 changes: 72 additions & 1 deletion reference/7.4/Microsoft.PowerShell.Core/About/about_CommonParameters.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
---
description: Describes the parameters that can be used with any cmdlet.
Locale: en-US
ms.date: 07/02/2024
ms.date: 04/24/2025
no-loc: [Debug, Verbose, Confirm]
online version: https://learn.microsoft.com/powershell/module/microsoft.powershell.core/about/about_commonparameters?view=powershell-7.4&WT.mc_id=ps-gethelp
schema: 2.0.0
Expand Down Expand Up @@ -459,6 +459,77 @@ Name Value
temp
```

> [!CAUTION]
> There are two known issues with using the **PipelineVariable** parameter in a
> pipeline that includes CimCmdlets or CDXML cmdlets. In the following
> examples, `Get-Partition` is a CDXML function and `Get-CimInstance` is a
> CimCmdlet.

1. When the first command is a CDXML function and downstream contains either a
CimCmdlet cmdlet or CDXML function, **PipelineVariable** is reset to
`$null`.

```powershell
Get-Partition -pv pvar |
ForEach-Object {
Write-Host "Before: $($pvar.PartitionNumber)"
[pscustomobject]@{Filter = "Index = $($_.DiskNumber)"}
} |
Get-CimInstance Win32_DiskDrive |
ForEach-Object {
Write-Host "After: $($pvar.PartitionNumber)"
}
```

Notice that the value of `$pvar` set to `$null` in the pipeline for the
second `ForEach-Object` command.

```Output
Before: 1
Before: 1
Before: 2
Before: 3
Before: 4
Before: 1
After:
After:
After:
After:
After:
After:
```

1. When the preceding command is _not_ a CDXML command and the downstream
contains either command type, the **PipelineVariable** remains as the last
accumulated object.

```powershell
Get-CimInstance Win32_DiskDrive -pv pvar |
ForEach-Object {
Write-Host "Before: $($pvar.Index)"
[pscustomobject]@{ DiskNumber = $_.Index }
} |
Get-Partition |
ForEach-Object {
Write-Host "After: $($pvar.Index)"
}
```

Notice that the value of `$pvar` set to the last object in the pipeline for
the second `ForEach-Object` command.

```Output
Before: 1
Before: 2
Before: 0
After: 0
After: 0
After: 0
After: 0
After: 0
After: 0
```

### -ProgressAction

Determines how PowerShell responds to progress updates generated by a script,
Expand Down
73 changes: 72 additions & 1 deletion reference/7.5/Microsoft.PowerShell.Core/About/about_CommonParameters.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
---
description: Describes the parameters that can be used with any cmdlet.
Locale: en-US
ms.date: 07/02/2024
ms.date: 04/24/2025
no-loc: [Debug, Verbose, Confirm]
online version: https://learn.microsoft.com/powershell/module/microsoft.powershell.core/about/about_commonparameters?view=powershell-7.5&WT.mc_id=ps-gethelp
schema: 2.0.0
Expand Down Expand Up @@ -459,6 +459,77 @@ Name Value
temp
```

> [!CAUTION]
> There are two known issues with using the **PipelineVariable** parameter in a
> pipeline that includes CimCmdlets or CDXML cmdlets. In the following
> examples, `Get-Partition` is a CDXML function and `Get-CimInstance` is a
> CimCmdlet.

1. When the first command is a CDXML function and downstream contains either a
CimCmdlet cmdlet or CDXML function, **PipelineVariable** is reset to
`$null`.

```powershell
Get-Partition -pv pvar |
ForEach-Object {
Write-Host "Before: $($pvar.PartitionNumber)"
[pscustomobject]@{Filter = "Index = $($_.DiskNumber)"}
} |
Get-CimInstance Win32_DiskDrive |
ForEach-Object {
Write-Host "After: $($pvar.PartitionNumber)"
}
```

Notice that the value of `$pvar` set to `$null` in the pipeline for the
second `ForEach-Object` command.

```Output
Before: 1
Before: 1
Before: 2
Before: 3
Before: 4
Before: 1
After:
After:
After:
After:
After:
After:
```

1. When the preceding command is _not_ a CDXML command and the downstream
contains either command type, the **PipelineVariable** remains as the last
accumulated object.

```powershell
Get-CimInstance Win32_DiskDrive -pv pvar |
ForEach-Object {
Write-Host "Before: $($pvar.Index)"
[pscustomobject]@{ DiskNumber = $_.Index }
} |
Get-Partition |
ForEach-Object {
Write-Host "After: $($pvar.Index)"
}
```

Notice that the value of `$pvar` set to the last object in the pipeline for
the second `ForEach-Object` command.

```Output
Before: 1
Before: 2
Before: 0
After: 0
After: 0
After: 0
After: 0
After: 0
After: 0
```

### -ProgressAction

Determines how PowerShell responds to progress updates generated by a script,
Expand Down
73 changes: 72 additions & 1 deletion reference/7.6/Microsoft.PowerShell.Core/About/about_CommonParameters.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
---
description: Describes the parameters that can be used with any cmdlet.
Locale: en-US
ms.date: 07/02/2024
ms.date: 04/24/2025
no-loc: [Debug, Verbose, Confirm]
online version: https://learn.microsoft.com/powershell/module/microsoft.powershell.core/about/about_commonparameters?view=powershell-7.6&WT.mc_id=ps-gethelp
schema: 2.0.0
Expand Down Expand Up @@ -459,6 +459,77 @@ Name Value
temp
```

> [!CAUTION]
> There are two known issues with using the **PipelineVariable** parameter in a
> pipeline that includes CimCmdlets or CDXML cmdlets. In the following
> examples, `Get-Partition` is a CDXML function and `Get-CimInstance` is a
> CimCmdlet.

1. When the first command is a CDXML function and downstream contains either a
CimCmdlet cmdlet or CDXML function, **PipelineVariable** is reset to
`$null`.

```powershell
Get-Partition -pv pvar |
ForEach-Object {
Write-Host "Before: $($pvar.PartitionNumber)"
[pscustomobject]@{Filter = "Index = $($_.DiskNumber)"}
} |
Get-CimInstance Win32_DiskDrive |
ForEach-Object {
Write-Host "After: $($pvar.PartitionNumber)"
}
```

Notice that the value of `$pvar` set to `$null` in the pipeline for the
second `ForEach-Object` command.

```Output
Before: 1
Before: 1
Before: 2
Before: 3
Before: 4
Before: 1
After:
After:
After:
After:
After:
After:
```

1. When the preceding command is _not_ a CDXML command and the downstream
contains either command type, the **PipelineVariable** remains as the last
accumulated object.

```powershell
Get-CimInstance Win32_DiskDrive -pv pvar |
ForEach-Object {
Write-Host "Before: $($pvar.Index)"
[pscustomobject]@{ DiskNumber = $_.Index }
} |
Get-Partition |
ForEach-Object {
Write-Host "After: $($pvar.Index)"
}
```

Notice that the value of `$pvar` set to the last object in the pipeline for
the second `ForEach-Object` command.

```Output
Before: 1
Before: 2
Before: 0
After: 0
After: 0
After: 0
After: 0
After: 0
After: 0
```

### -ProgressAction

Determines how PowerShell responds to progress updates generated by a script,
Expand Down