[Misc.] Add `az.ps1` entry script for PowerShell

[jiasli]

Context

Fix https://github.com/Azure/azure-cli/issues/20972

If an argument contains special characters like | and &, even though the character is double quoted, it still gets executed. This is because PowerShell launches cmd.exe to execute az.cmd script. Double quotes are parsed by PowerShell so not passed to cmd.exe during this process. cmd.exe sees the raw | and & and executes them.

However, when az.cmd is invoked from cmd.exe (Command Prompt), it is launched in-process, and double quotes are preserved, leading to inconsistent behavior between cmd.exe and PowerShell.

Change

This PR adds az.ps1 entry script for PowerShell, so that PowerShell can natively execute az.ps1 and no longer launches cmd.exe to execute az.cmd.

Since PowerShell 7.3, double quotes are now preserved correctly when calling a native executable(https://github.com/PowerShell/PowerShell/issues/1995#issuecomment-1211457683), thus fixing https://github.com/Azure/azure-cli/issues/15529.

Testing Guide

az --debug '"ab"'
cli.knack.cli: Command arguments: ['--debug', '"ab"']

az --debug "a|b"
cli.knack.cli: Command arguments: ['--debug', 'a|b']

az --debug "a&b"
cli.knack.cli: Command arguments: ['--debug', 'a&b']

TODO

This az.ps1 should be code-signed.

[yonzhan]

add a ps1 file as the entry script to bypass 'PowerShell -> cmd' issue.

[jiasli]

By the way, I am playing around by calling cmd.exe (https://ss64.com/nt/cmd.html) myself from Command Prompt and it looks like it has some weird behavior that I need to add extra double quotes (denoted by ^):

According to https://ss64.com/nt/syntax-esc.html

To launch a batch script with spaces in the script Path and other parameters, all requiring quotes:

CMD /k ""c:\batch files\test.cmd" "Parameter 1 with space" "Parameter2 with space""
       ^                                                                          ^

My testing:

D:\test.cmd contains

@echo %*

D:\>cmd /c "D:\test.cmd" "parameter1 parameter2"
'D:\test.cmd" "parameter1' is not recognized as an internal or external command,
operable program or batch file.

D:\>cmd /c ""D:\test.cmd" "parameter1 parameter2""
"parameter1 parameter2"

While in Bash

/home/user2/test.sh contains

echo "$@"

user2@DESKTOP-A79F1:~$ bash "/home/user2/test.sh" "parameter1 parameter2"
parameter1 parameter2
user2@DESKTOP-A79F1:~$ bash ""/home/user2/test.sh" "parameter1 parameter2""
bash: /home/user2/test.sh parameter1: No such file or directory

No weird outer double quotes are needed.

[jiasli]

I also found another weird PowerShell behavior while writing this PR - PowerShell sometimes even depends on the space location to determine the behavior:

> python -c "import sys; print(sys.argv)" '\"a b\"c'
['-c', '"a', 'b"c']
> python -c "import sys; print(sys.argv)" '\"ab\" c'
['-c', '"ab" c']

Also consider these commands:

> python -c "import sys; print(sys.argv)" '""a b""'
['-c', '"a b"']
> python -c "import sys; print(sys.argv)" '\"a b\"'
['-c', '"a', 'b"']

They should be grammatically equivalent, as in Win32 API within double quotes, "" and \" both mean literal double quote sign. However, they are not, because in the second example, PowerShell somehow recognizes double quotes and thinks space is not “on the root level of the string”, so doesn’t surround the argument with double quotes when passing it to python.exe, making the argument split.

> python -c "import sys; print(sys.argv)" '\"a b\" '
['-c', '"a b" ']

In the above example, I put an extra space “on the root level” and PowerShell passed the arguments double-quoted-ly to python.exe.

[a3code]

Hello everyone, could please explain how I should run scripts right now I am a little bit confused, on azure DevOps I have a script that had run az in the next way: Start-Process "az" -ArgumentList $azArgs -NoNewWindow -Wait azArgs is a commend to set some settings that is. and currently I see an error : Start-Process : This command cannot be run due to the error: %1 is not a valid Win32 application how do I need to change it to make it work after this fix? Should I just remove Start-Process ?

[yonzhan]

We will revert this script and roll out on 10.12. Everything will work normally by then.

[ishepherd]

@jiasli @yonzhan Will you be adding test coverage for all the many issues people are reporting? Looks like a nice opportunity to fill coverage gaps.