Add-Member : Cannot bind argument to parameter 'InputObject' because it is null.

[Richard Kuhnt]

#16 has introduced a new problem with:

Install/install.ps1

Line 344 in 14079ad

 if ($null -eq $scoopConfig -or $scoopConfig.Count -eq 0) { 

Both checks return false and we get:

PS C:\Users\appveyor> .\install.ps1 -RunAsAdmin
Initializing...
Downloading...
Extracting...
Creating shim...
- Add-Member : Cannot bind argument to parameter 'InputObject' because it is null.
- At C:\Users\appveyor\install.ps1:357 char:28
- + ... oopConfig | Add-Member -MemberType NoteProperty -Name $Name -Value $V ...
- +                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-     + CategoryInfo          : InvalidData: (:) [Add-Member], - ParameterBindingValidationException
-     + FullyQualifiedErrorId : - ParameterArgumentValidationErrorNullNotAllowed,Microsoft.PowerShell.Commands.AddMemberCommand

[Richard Kuhnt]

It's now an array containing one element of $null

[Chawye Hsu]

Maybe we should apply the fix to line 328:

return @(Get-Content $SCOOP_CONFIG_FILE -Raw | ConvertFrom-Json -ErrorAction Stop)

instead of line 342:

$scoopConfig = @(Use-Config)

@r15ch13 can you test it? /cc @MarkMichaelis

[Richard Kuhnt]

I can't even reproduce the error from #15. The code used in Core is still the same and works.

https://github.com/lukesampson/scoop/blob/a9fa775d59b14e7dce335313faa0eff855469764/lib/core.ps1#L38-L48

What I find strange, is the error message @MarkMichaelis posted was caused by line 404

[Chawye Hsu]

I can't even reproduce the error from #15. The code used in Core is still the same and works.

Have you tweaked Set-StrictMode -Version Latest? Set strict mode and the error will occur in PS5.

[Richard Kuhnt]

Okay, that was not mentioned 😁

[Chawye Hsu]

Set-StrictMode -Version Latest

# powershell 5
("{}" | ConvertFrom-Json -ErrorAction Stop).Count
# The property 'Count' cannot be found on this object. Verify that the property exists.
# At line:1 char:1
# + ("{}" | ConvertFrom-Json -ErrorAction Stop).Count
# + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#     + CategoryInfo          : NotSpecified: (:) [], PropertyNotFoundException
#     + FullyQualifiedErrorId : PropertyNotFoundStrict


# powershell 6+
("{}" | ConvertFrom-Json -ErrorAction Stop).Count
# 1

[Richard Kuhnt]

I guess .Count makes no sense anyway because it will always return 1.

/Edit: Nice, it was me who added this check ScoopInstaller/Scoop@630ba04
I should probably enable StrictMode on my system for testing. 😄

[Chawye Hsu]

Disabling StrictMode is the default setting in PowerShell and it's easier for developers to develop scripts, however, some users have StrictMode enabled in their computers.

I think we should force StrictMode to a value in the installer script.

[Richard Kuhnt]

I guess we could change the check to

if ($scoopConfig -isnot [System.Management.Automation.PSObject]) { 

Enforcing StrictMode for the installer should be possible.
For Scoop itself it would require a rewrite 😁

[Chawye Hsu]

A special case, assuming the content of config.json is [1,2]:

("[1,2]" | ConvertFrom-Json) -isnot [System.Management.Automation.PSObject]
# True in PowerShell 6+

("[1,2]" | ConvertFrom-Json) -isnot [System.Management.Automation.PSObject]
# False in PowerShell 5. Damn it! It will escape from the if condition flow
$scoopConfig = ("[1,2]" | ConvertFrom-Json)
$scoopConfig | Add-Member -MemberType NoteProperty -Name "debug" -Value "true"
$scoopConfig | ConvertTo-Json
#[
#    {
#        "value":  1,
#        "debug":  "true"
#    },
#    {
#        "value":  2,
#        "debug":  "true"
#    }
#]
# <---- causing unexpected behavior. 😄

Although I don't think any user would like to edit and save config.json with an array([1,2]).

/edit: patch diff https://github.com/ScoopInstaller/Install/compare/h404bi-patch-1?expand=1