'using:' and other methods not working with start-threadJob to load objects into job session

running the following returns an error:

$job=Start-ThreadJob -name maya6 -InitializationScript {. $using:profile} -ScriptBlock {ichild}   #this is an alias defined in the profile

error:

InvalidOperation: A Using variable cannot be retrieved. A Using variable can be used only with Invoke-Command, Start-Job, or InlineScript in the script workflow. When it is used with Invoke-Command, the Using variable is valid only if the script block is invoked on a remote computer.
ichild: The term 'ichild' is not recognized as a name of a cmdlet, function, script file, or executable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.

I also tried:

$job=start-threadJob {. $args ; ichild} -ArgumentList $profile      #ichild is an alias defined in my profile

and when I use receive-job $job it freezes my prompt and I keep getting the following error:

Oops, something went wrong.  
Please report this bug with ALL the details below, including both the 'Environment' and 'Exception' sections.  
Please report on GitHub: https://github.com/PowerShell/PSReadLine/issues/new?template=Bug_Report.yaml  
Thank you!  
  
### Environment  
PSReadLine: 2.3.4  
PowerShell: 7.4.6  
OS: Microsoft Windows 10.0.26100  
BufferWidth: 170  
BufferHeight: 21  
  
Last 49 Keys:

I thought using was for specifically this commandlet...

am on pwsh7.4

Solution

You're seeing a long-standing bug - see GitHub issue #4530 - that was initially reported in 2017, which affects both Windows PowerShell (the legacy, ships-with-Windows, Windows-only edition of PowerShell whose latest and last version is 5.1) and PowerShell (Core) 7 as of v7.5.0; it has received little attention since then, unfortunately.
In short: Start-Job as well as well as Start-ThreadJob unexpectedly do not support $using: references in script blocks passed to the -InitializationScript parameter, unlike with the -ScriptBlock parameter.

Workarounds:

Either: Add the code you meant to pass to -InitializationScript to the main script block passed to the -ScriptBlock parameter, where $using: references are supported; applied to your case:
```
Start-ThreadJob -ScriptBlock { . $using:profile; ichild } -name maya6 
```
Or: If feasible, use string interpolation to "bake" the values from the caller's scope into a string from which you can create a script block; applied to your case:
```
Start-ThreadJob -InitializationScript ([scriptblock]::Create(". `"$profile`"")) -ScriptBlock { ichild } -name maya6 
```

Caveat:

Your $PROFILE file may act differently when dot-sourced from a thread job (parallel runspace) or background job (child process): for instance, the value of the automatic $PROFILE is not defined there.
The same applies to the PowerShell 7-only -Parallel feature of ForEach-Object, which uses parallel runspaces (threads) too.
The Oops, something went wrong. error you're seeing relates to the PSReadLine module; importing it into a parallel runspace is pointless, as its sole purpose is to enrich the interactive command-line editing experience.
Without knowing the details of your specific profile, it's impossible to diagnose the problem, but perhaps you can bypass the problem by enclosing any PSReadLine-related code in your profile in if (-not $PROFILE) { ... }, so as to exclude it when the profile is dot-sourced from a (thread) job.