Since 7.4.0, Group-Object cannot group strings containing curly braces

[cschneegans]

Prerequisites

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• Refer to the FAQ.
• Refer to Differences between Windows PowerShell 5.1 and PowerShell.

Steps to reproduce

Since 7.4.0, it appears that the Group-Object cmdlet tries to interpret its string input as .NET format strings.

If a string contains curly braces (U+007B and U+007D), the Group-Object cmdlet throws exceptions associated with the [string]::Format method or the -f operator.

Expected behavior

PS> '{' | Group-Object -NoElement;

Count Name
----- ----
    1 {

PS> '}' | Group-Object -NoElement;

Count Name
----- ----
    1 }

Actual behavior

PS> '{' | Group-Object -NoElement;
Group-Object: Input string was not in a correct format. Failure to parse near offset 1. Expected an ASCII digit.

PS> '}' | Group-Object -NoElement;
Group-Object: Input string was not in a correct format. Failure to parse near offset 1. Unexpected closing brace without a corresponding opening brace.

Error details

Exception             : 
    Type       : System.FormatException
    TargetSite : 
        Name          : ThrowFormatInvalidString
        DeclaringType : System.ThrowHelper, System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e
        MemberType    : Method
        Module        : System.Private.CoreLib.dll
    Message    : Input string was not in a correct format. Failure to parse near offset 1. Unexpected closing brace without a corresponding opening brace.
    Source     : System.Private.CoreLib
    HResult    : -2146233033
    StackTrace : 
   at System.Text.StringBuilder.AppendFormatHelper(IFormatProvider provider, String format, ReadOnlySpan`1 args)
   at System.Text.StringBuilder.AppendFormat(IFormatProvider provider, String format, Object[] args)
   at Microsoft.PowerShell.Commands.GroupInfo.BuildName(List`1 propValues)
   at Microsoft.PowerShell.Commands.GroupInfo..ctor(OrderByPropertyEntry groupValue)
   at Microsoft.PowerShell.Commands.GroupObjectCommand.DoOrderedGrouping(OrderByPropertyEntry currentObjectEntry, Boolean noElement, List`1 groups, Dictionary`2 groupInfoDictionary, OrderByPropertyComparer orderByPropertyComparer)
   at Microsoft.PowerShell.Commands.GroupObjectCommand.EndProcessing()
   at System.Management.Automation.CommandProcessorBase.Complete()
CategoryInfo          : NotSpecified: (:) [Group-Object], FormatException
FullyQualifiedErrorId : System.FormatException,Microsoft.PowerShell.Commands.GroupObjectCommand
InvocationInfo        : 
    MyCommand        : Group-Object
    ScriptLineNumber : 1
    OffsetInLine     : 7
    HistoryId        : 9
    Line             : '}' | Group-Object -NoElement;
    Statement        : Group-Object -NoElement
    PositionMessage  : At line:1 char:7
                       + '}' | Group-Object -NoElement;
                       +       ~~~~~~~~~~~~~~~~~~~~~~~
    InvocationName   : Group-Object
    CommandOrigin    : Internal
ScriptStackTrace      : at <ScriptBlock>, <No file>: line 1

Environment data

Name                           Value
----                           -----
PSVersion                      7.4.0
PSEdition                      Core
GitCommitId                    7.4.0
OS                             Microsoft Windows 10.0.22631
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

[mawosoft]

Seems to have been introduced in #20608.
This accidentally reverts the use of StringBuilder.Append(CultureInfo, $"{interpolated}") (added in #18978) back to StringBuilder.AppendFormat(), but keeps the interpolated string instead of using "{0}", value, i.e. the value becomes the format string.

[microsoft-github-policy-service]

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🔗 https://forms.office.com/r/P926k48jRJ

Microsoft Forms

[sba923]

We'll be able to test the fix in the first 7.4.1 preview, correct?

[iSazonov]

@sba923 Yes. And it is already in daily build (link is on main page).