PowerShell & operator launches commands differently in 7.3.0

Prerequisites

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

Steps to reproduce

Build C# app called blah.exe using Program.cs, make sure it's on the path.
Run pwsh -f test.ps1 and observe the output.

Expected behavior

On 7.2.7:

Something will happen: working...
Something will happen: done.
--set
deployment.environment=blah
--set
deployment.region=blah
--set
deployment.image.repository=blah

Actual behavior

On 7.3.0:

Something will happen: working...
Something will happen: done.
--set
deployment.environment="blah"
--set
deployment.region="blah"
--set
deployment.image.repository="blah"

Error details

No response

Environment data

Name                           Value
----                           -----
PSVersion                      7.3.0
PSEdition                      Core
GitCommitId                    7.3.0
OS                             Microsoft Windows 10.0.19044
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

Nov 15 '22 21:11 wasker

This is ultimately a duplicate of #18554, but let me add some context:

v7.3.0 introduced a breaking change with respect to how arguments with embedded " characters as well as empty-string arguments are passed to external programs: a longstanding bug was fixed, fully on Unix, partially on Windows.
- Update: It looks like this breaking change may get reverted in some version after v7.3.1 so as to make it opt-in rather than opt-out, but on Windows only - see #18694
Existing workarounds that build on the old, broken behavior now break - except in calls to batch files and WSH scripts, where the legacy workarounds will continue to work by default.
- To make such legacy workarounds work in v7.3.0, you need to set the $PSNativeCommandArgumentPassing preference variable (temporarily) to 'Legacy'
- For a summary of the impact on existing vs. future code, see this comment.
The fixed behavior now correctly escapes embedded " characters as \" on the process command line PowerShell constructs behind the scenes, which is the most widely observed convention on Windows, and also supports passing empty strings as arguments.
- Thus, an argument such as "deployment.environment=`"blah`"", which from PowerShell's perspective has a verbatim value of deployment.environment="blah" is now placed as follows on the target process' command line: "deployment.environment=\"blah\"", and if the target process observes the aforementioned convention, it ends up parsing that again as verbatim deployment.environment="blah", which is what you saw.

There's additional background information in this Stack Overflow answer.

Nov 15 '22 21:11 mklement0

Thank you for the links!

There's no mention of this behavior change in relnotes for 7.3.0 - https://github.com/PowerShell/PowerShell/releases/tag/v7.3.0

GitHub
Release v7.3.0 Release of PowerShell · PowerShell/PowerShell
7.3.0 - 2022-11-08 General Cmdlet Updates and Fixes
Correct calling cmdlet New-PSSessionOption in script for Restart-Computer (#18374)

Tests

Add test for framework dependent package in release p...

Nov 15 '22 22:11 wasker

My pleasure, @wasker.

There's no mention of this behavior change in relnotes for 7.3.0 -https://github.com/PowerShell/PowerShell/releases/tag/v7.3.0

That GitHub link doesn't provide a cumulative view of what changed in that release - it just shows whatever changed in the final commit that led to the release.

While you could infer the cumulative changes from https://github.com/PowerShell/PowerShell/releases, the official what's-new summary for a given release should be at https://learn.microsoft.com/en-us/powershell/scripting/whats-new/overview
However, as of this writing, https://learn.microsoft.com/en-us/powershell/scripting/whats-new/what-s-new-in-powershell-73 does not contain the relevant information.
The PowerShell Team blog at https://devblogs.microsoft.com/powershell/powershell-7-3-general-availability/ at least mentions the feature that caused the breaking change, but, to my mind, that description is inadequate, given that the fact that it is breaking isn't even mentioned.
- As an aside: The post also suggests that the experimental PSNativeCommandErrorActionPreference was made stable, but from what I can tell that isn't actually the case.

GitHub
Release v7.3.0 Release of PowerShell · PowerShell/PowerShell
7.3.0 - 2022-11-08 General Cmdlet Updates and Fixes
Correct calling cmdlet New-PSSessionOption in script for Restart-Computer (#18374)

Tests

Add test for framework dependent package in release p...

GitHub
Releases · PowerShell/PowerShell
PowerShell for every system! Contribute to PowerShell/PowerShell development by creating an account on GitHub.

Overview of what's new in PowerShell - PowerShell
A collection of release notes and documentation about the new features available in new versions of PowerShell.

What's New in PowerShell 7.3 - PowerShell
New features and changes released in PowerShell 7.3

PowerShell Team
PowerShell 7.3 General Availability
General availability of PowerShell 7.3

Nov 15 '22 23:11 mklement0

cc @michaeltlombardi

The content team should have plans to have an about topic specifically around using native commands in PS7 and I expect will capture these types of details

Nov 16 '22 01:11 SteveL-MSFT