Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest released version
• Search the existing issues.
• Refer to the FAQ.
• Refer to Differences between Windows PowerShell 5.1 and PowerShell.

Steps to reproduce

This was tested on PowerShell 7.4.2

1. Download the .NET 8.0 installer for Windows x64 to use as the test file, the direct link to this is here: https://dotnet.microsoft.com/en-us/download/dotnet/thank-you/sdk-8.0.204-windows-x64-installer
2. Save this file into a folder on your computer somewhere
3. Create a PowerShell script with the following contents in the same folder as the .NET 8.0 installer:

Get-Date
Write-Host "Creating Path to dotnet.exe test file"
$file = Join-Path -Path $PSScriptRoot -ChildPath "dotnet.exe"
Write-Host "Reading all file bytes into memory"
$bytes = [System.IO.File]::ReadAllBytes( $file )
Write-Host "Converting file bytes to base64 string"
$base64 = [System.Convert]::ToBase64String( $bytes )
Write-Host "Converting base64 string back to file bytes"
$bytes = [System.Convert]::FromBase64String( $base64 )
Write-Host "Test complete"
Get-Date

NOTE: That if you test this with a newer version of the .NET 8.0 installer, you may have to modify the test script to pick the correct file for the test since the filename is hard coded on line 3.

4. Open a PowerShell window in the folder with the script and test file
5. Run the PowerShell script
6. Open Task Manager and observe the memory usage of PowerShell
7. Note the time required to complete the conversion from Base64 and the usage of upwards of 3.5 GB of RAM to do so

The .NET 8.0 installer for Windows x64 is approximately 222 MB in size. Reading into memory and converting to base64 then converting back should require about 790 MB of RAM with all variables remaining in scope during the process and no garbage collection happening or object disposal happening. The observed behavior appears to be memory-leak related as the amount of memory used once the conversion eventually completes is about 3.4 GB of RAM. These data points can be see in the attached screen shots.

Expected behavior

When you run the same script in PowerShell 7 and Windows PowerShell 5.1, you see two very different behaviors:

In PowerShell 7.4.2, the time to complete is 82 seconds and memory used is 3.4 GB
In PowerShell 5.1, the time to complete is 7 seconds and memory used is 1.0 GB

This suggests there is an error in the PowerShell 7.4.2 / .NET 8.0 implementation.

Actual behavior

In PowerShell 7.4.2, the time to complete is 82 seconds and memory used is 3.4 GB.

Error details

No response

Environment data

Name                           Value
----                           -----
PSVersion                      7.4.2
PSEdition                      Core
GitCommitId                    7.4.2
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

Testing in PowerShell 7.4.2

Testing in PowerShell 5.1

PowerShell 7.4.2 Memory Usage

PowerShell 5.1 Memory Usage