`Write-Debug` expands `-Message` when it should `SilentlyContinue`

[iRon7]

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Steps to reproduce

Write-Debug and Write-Verbose expand the -Message where the commands should SilentlyContinue.

Use case:
I am using a class with has a lazy evaluation (because not all results always require to be evaluated).
It concerns a recursive script where I would like to add some Write-Debug commands, like:

Write-Debug "This takes 3 seconds $(Sleep 3)"

Expected behavior

When the -Debug switch is omitted for my script, the script shouldn't take more time because of the debug commands.
In other words, the -Message should not be evaluated.

Actual behavior

When the -Debug switch is omitted for my script, the -Message is evaluated and takes 3 secondes (for the example).

Workaround

Function test {
    [CmdletBinding()] param() 
    if ($DebugPreference -in 'Stop', 'Continue', 'Inquire') { Write-Debug "Test $(Sleep 3)" }
}

Environment data

Name                           Value
----                           -----
PSVersion                      7.3.10
PSEdition                      Core
GitCommitId                    7.3.10
OS                             Microsoft Windows 10.0.19045
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Visuals

No response

[rhubarb-geek-nz]

I expect the evaluation of the message is done before Write-Debug is invoked.

For this to work you would need Write-Debug to do the expansion and formatting depending on the current environment.

However the parameter -Message is defined as a string so the parameter expansion is going to try and evaluate it to a single string before invoking the cmdlet.

If it was defined as an object and Write-Debug used ToString then you could have delayed the expansion by creating an object where the message is expanded and formatted in the ToString method.

[iRon7]

@rhubarb-geek-nz,

If it was defined as an object and Write-Debug used ToString then you could have delayed the expansion by creating an object where the message is expanded and formatted in the ToString method.

Agree, if not easy/possible to create a syntactic sugar for this, it would be nice if the concerned commands would have something like a [ScriptBlock]$MessageScript (mutual exclusive with -Message) parameter.

Wishful thinking:

Write-Debug { "This takes 3 seconds $(Sleep 3)" }

[jhoneill]

Side track... I have a write-logfile function, and in one of my scripts that call scripts I have proxy functions for Write-Information, Write-Debug, Write-Error, write-warning, and Write-verbose so they all go to a big text file and then call the underlying write- command so the info is still visible. It wouldn't take much to have a Write-Debug proxy function which did processed script blocks, but only if the debugpreference indicated they would be output.

[iRon7]

Another side effect for this issue is that a (debug) statement as:

Write-Debug "Password: $(ConvertFrom-SecureString -AsPlainText $SecureString)"

will (presumably) reveal the password in memory even it is not displayed (for debugging).