Don't throw PowerShell exception on writes to stderr from external command

tl;dr

The simplest workaround for the PowerShell ISE is the following (not needed in a regular console or in Visual Studio Code):

# Redirect stderr (2) to the success stream (1).# Doing so wraps stderr lines in [System.Management.Automation.ErrorRecord]# instances; calling .ToString() on them returns them as normal text.# CAVEAT: BE SURE THAT $ErrorActionPreference = 'Stop' is NOT IN EFFECT.git checkout devel 2>&1 | % ToString 

^{For other workarounds, including the ability to distinguish lines by stream of origin, see this answer.}

However, you're better off switching to Visual Studio Code as your development environment, which solves the problem fundamentally - see below.

Two asides:

• What you're seeing are non-terminating errors, not exceptions (while .NET exceptions underly PowerShell's error handling, they are always wrapped in [System.Management.Automation.ErrorRecord] instances and may or may not abort execution (terminating vs. non-terminating error)).

• try / catch doesn't catch non-terminating errors, only terminating ones; while you could set $ErrorActionPreference = 'Stop' beforehand to promote non-terminating errors to terminating ones, execution of your program (in the ISE ) would be aborted on receiving the first stderr line.

You can avoid this problem if you limit your PowerShell use to:

• a terminal (console), including the upcoming Windows Terminal

• Visual Studio Code with the PowerShell extension; this cross-platform editor (IDE) is meant to supersede the obsolescent Windows PowerShell ISE.

These environments behaves as you would expect:

• stderr (standard error) output is passed through to the display by default
• stderr lines print just like regular lines.

Note:

• In the context of remoting and background jobs, stderr output is still sent to PowerShell's error stream.

• There are additional, host-independent problems with the use of 2> with external programs.

See this answer for a comprehensive overview of all problems.

How do I prevent native commands in a PowerShell script from throwing an exception on writes to stderr without completely blocking stderr?

You can try, with Git 2.16+, the option I mentioned in "PowerShell Capture Git Output"

 set GIT_REDIRECT_STDERR=2>&1

Check then if everything is written in stdout.

I usually redirrect ALL outputs to the same destination:

Invoke-Command -ScriptBlock {get-module} *>&1 

Or sometime I throw it into a file:

$scriptblock = {    get-module}Invoke-Command -ScriptBlock $scriptblock *>&1 >> file.txt