Return casesensitive hashtable with Group-Object

Steps to reproduce

I know PowerShell is mostly case insensitive, but when using both -AsHashTable and -CaseSensitive I expected to end up with a case sensitive hashtable.

$capitonyms = @(
    [PSCustomObject]@{
        Capitonym = 'Bill'
    }
    [PSCustomObject]@{
        Capitonym = 'bill'
    }
)

$capitonyms | Group-Object Capitonym -AsHashTable -CaseSensitive

Expected behavior

Name                           Value
----                           -----
Bill                           {@{Capitonym=Bill}}
bill                           {@{Capitonym=bill}}

Actual behavior

Group-Object : The objects grouped by this property cannot be expanded because there is a key duplication. Provide a valid value for the property, and then try again.
At line:1 char:15
+ $capitonyms | Group-Object Capitonym -AsHashTable -CaseSensitive
+               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : InvalidArgument: (:) [Group-Object], Exception
+ FullyQualifiedErrorId : The objects grouped by this property cannot be expanded because there is a key duplication. Provide a valid value for the property, and then try again.,Microsoft.PowerShell.Commands.GroupObjectCommand

Environment data

Name                           Value
----                           -----
PSVersion                      7.0.0-preview.3
PSEdition                      Core
GitCommitId                    7.0.0-preview.3
OS                             Microsoft Windows 10.0.18362
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

[mklement0]

since this cmdlet was envisioned as grouping objects by .NET property name

Grouping happens by property value, not name, and given that omitting -AsHashtable already works exactly as advertised:

PS> $capitonyms | Group-Object Capitonym -CaseSensitive

Count Name                      Group
----- ----                      -----
    1 bill                      {@{Capitonym=bill}}
    1 Bill                      {@{Capitonym=Bill}}

so should the variant with -AsHashtable.

So I don’t see a breaking change here, only a bug fix.

Users who opt for combining -CaseSensitive with -AsHashtable will have to be aware that the resulting hashtable will have case-sensitive key lookups, unlike regular PowerShell hashtables, but since -CaseSensitive is an explicit opt-in, that seems reasonable.

[vexx32]

I mean, if -CaseSensitive doesn’t already make it explicit, we’re kind of out of options for making it explicit. 😂