I found problem in PowerShell 7.5.4. After installing 7.6 preview the problem still exists.

Short: PowerShell does not accept empty string as a parameter value, direct or piped ByValue. The problem happens with simple [string] or array of strings [string[]]. The reported error is Cannot bind argument to parameter 'InputObject' because it is an empty string.

As result you cannot e.g. pipe output from Get-Content to any script when piped file contains ampty lines.

Very bad workaround for the problem is to declare parameter as [System.Object] and retyping it as a [System.string] inside but this will not work when you want to check/recognize type of piped ByValue objects.

The script to test this issue looks like below:

[CmdletBinding()]
Param ()

Function Show-Object
{
    param (
        $object
    )
    if ($Null -eq $object)
    {
        '$InputObject is $null'
    }
    else
    {
        "`$InputObject is $($object.GetType()) = $($object)"
    }
} # Show-Object


Function StringArray
{
    [CmdletBinding()]
    param (
        [Parameter(Mandatory=$true,
                ValueFromPipeline=$true)]
        [System.String[]] $InputObject
    )

    Begin
    {
        Write-Verbose "StringArray: Entering Begin block, $(Show-Object $InputObject)"
    }

    Process
    {
        Write-Verbose "StringArray: Entering Process block, $(Show-Object $InputObject)"
    }

    End
    {
        Write-Verbose "StringArray: Entering End block, $(Show-Object $InputObject)"
        Write-Verbose ''
    }
} # Function StringArray

Function SimpleString
{
    [CmdletBinding()]
    param (
        [Parameter(Mandatory=$true,
                ValueFromPipeline=$true)]
        [System.String] $InputObject
    )

    Begin
    {
        Write-Verbose "SimpleString: Entering Begin block, $(Show-Object $InputObject)"
    }

    Process
    {
        Write-Verbose "SimpleString: Entering Process block, $(Show-Object $InputObject)"
    }

    End
    {
        Write-Verbose "SimpleString: Entering End block, $(Show-Object $InputObject)"
        Write-Verbose ''
    }
} # Function SimpleString


StringArray -InputObject abc, def, gh
StringArray -InputObject 'abc', 'def', 'gh'
'abc', 'def', 'gh' | StringArray
StringArray -InputObject 'abc', '', 'gh'
'abc', '', 'gh' | StringArray

SimpleString -InputObject abc
SimpleString -InputObject 'abc'
'abc' | SimpleString
SimpleString -InputObject ''
'' | SimpleString

$PSVersionTable

The output of above script run with parameter verbose looks like below:
`
19.02.2026 12:31:58
adamm@SURFACE[PS(1)]:M:\Users\Adam\PRJs\PowerShell
$ .\Test-Param.ps1 -verbose
VERBOSE: StringArray: Entering Begin block, $InputObject is string[] = abc def gh
VERBOSE: StringArray: Entering Process block, $InputObject is string[] = abc def gh
VERBOSE: StringArray: Entering End block, $InputObject is string[] = abc def gh
VERBOSE:
VERBOSE: StringArray: Entering Begin block, $InputObject is string[] = abc def gh
VERBOSE: StringArray: Entering Process block, $InputObject is string[] = abc def gh
VERBOSE: StringArray: Entering End block, $InputObject is string[] = abc def gh
VERBOSE:
VERBOSE: StringArray: Entering Begin block, $InputObject is $null
VERBOSE: StringArray: Entering Process block, $InputObject is string[] = abc
VERBOSE: StringArray: Entering Process block, $InputObject is string[] = def
VERBOSE: StringArray: Entering Process block, $InputObject is string[] = gh
VERBOSE: StringArray: Entering End block, $InputObject is string[] = gh
VERBOSE:
StringArray: M:\Users\Adam\PRJs\PowerShell\Test-Param.ps1:75
Line |
75 | StringArray -InputObject 'abc', '', 'gh'
| ~~~~~~~~~~~~~~~
| Cannot bind argument to parameter 'InputObject' because it is an empty string.
VERBOSE: StringArray: Entering Begin block, $InputObject is $null
VERBOSE: StringArray: Entering Process block, $InputObject is string[] = abc
StringArray: M:\Users\Adam\PRJs\PowerShell\Test-Param.ps1:76
Line |
76 | 'abc', '', 'gh' | StringArray
| ~~~~~~~~~~~
| Cannot bind argument to parameter 'InputObject' because it is an empty string.
VERBOSE: StringArray: Entering Process block, $InputObject is string[] = gh
VERBOSE: StringArray: Entering End block, $InputObject is string[] = gh
VERBOSE:
VERBOSE: SimpleString: Entering Begin block, $InputObject is string = abc
VERBOSE: SimpleString: Entering Process block, $InputObject is string = abc
VERBOSE: SimpleString: Entering End block, $InputObject is string = abc
VERBOSE:
VERBOSE: SimpleString: Entering Begin block, $InputObject is string = abc
VERBOSE: SimpleString: Entering Process block, $InputObject is string = abc
VERBOSE: SimpleString: Entering End block, $InputObject is string = abc
VERBOSE:
VERBOSE: SimpleString: Entering Begin block, $InputObject is string =
VERBOSE: SimpleString: Entering Process block, $InputObject is string = abc
VERBOSE: SimpleString: Entering End block, $InputObject is string = abc
VERBOSE:
SimpleString: M:\Users\Adam\PRJs\PowerShell\Test-Param.ps1:81
Line |
81 | SimpleString -InputObject ''
| ~~
| Cannot bind argument to parameter 'InputObject' because it is an empty string.
VERBOSE: SimpleString: Entering Begin block, $InputObject is string =
SimpleString: M:\Users\Adam\PRJs\PowerShell\Test-Param.ps1:82
Line |
82 | '' | SimpleString
| ~~~~~~~~~~~~
| Cannot bind argument to parameter 'InputObject' because it is an empty string.
VERBOSE: SimpleString: Entering End block, $InputObject is string =
VERBOSE:

Name Value

PSVersion 7.6.0-preview.6
PSEdition Core
GitCommitId 7.6.0-preview.6
OS Microsoft Windows 10.0.26100
Platform Win32NT
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion 2.4
SerializationVersion 1.1.0.1
WSManStackVersion 3.0
`