Add new use_canonical_path option in rezconfig.py

[OlivierArgentieri]

Context:

It's because on windows, we can map some drive letter, to UNC network path.
To centralize packages but also software binaries.

Problem:

Some softwares like substance, vscode or RV, cannot be run on UNC path and will crash or freeze.

Solution:

Map a new drive letter on windows, using new-smbmapping for example, to avoid usage of unc path in PATH environment variable.
But, rez resolution plugin, use os.path.realpath directly in __init__ because of that, the path is converted back from our mapped drive letter to full unc path, so some binaries cannot be launched anymore.

Another solution, can be the usage of rez cache, but i found this solution not efficient rather than just execution of binary from network.

Final details:

It's why, i have created a new parameter in the rezconfig, to have an option to bypass the convertion of canonical path on resolution process, in case of mapped letter drive in packages_paths.

Obviously, by default i have set it to True, to not alterate the current behavior of rez resolution plugin.

Test:

• I have locally reinstall rez with theses modifications, then i have set the property use_canonical_path to False in the rezconfig.py to test and here the result i got:

PS C:\Users\oargentieri> rez env vscode-1.82

You are now in a rez-configured environment.

resolved by oargentieri@<hostname> on Thu Sep 28 10:50:16 2023, using Rez v2.113.0

requested packages:
vscode-1.82
~platform==windows  (implicit)
~arch==AMD64        (implicit)
~os==windows-10.0   (implicit)

resolved packages:
platform-windows  X:\rez_package\platform\windows
vscode-1.82.2     X:\rez_package\vscode\1.82.2\platform-windows

And now vscode can be launched using rez env vscode -- code --disable-chromium-sandbox

Issue:

• Have a new property to disable or enable canonical_path inside the rezconfig.py #1541
• Environment resolution uses UNC paths with Python 3.10, 3.7 was using mounted network drives. #1438

Also linked to this discussion

[JeanChristopheMorinPerso]

Thanks! I'm far from Windows expert so I'll let others chime in on if it's something we want or not. I'm also wondering why this has never come up before...

[maxnbk]

I've only skimmed, so I might be missing something, but...

Is this not essentially this issue manifesting? #1438

If so, I'm wondering if we shouldn't just apply this without a config value anyway?

[OlivierArgentieri]

I've only skimmed, so I might be missing something, but...

Is this not essentially this issue manifesting? #1438

If so, I'm wondering if we shouldn't just apply this without a config value anyway?

Actually yes I think it's related to #1438 , maybe the behavior of os.path.realpath has changed.

Introducing a new variable in config, will allow us to keep the behavior as it is, for example, on Linux, and to disable the canonicals path resolution on Windows or if an unc path are in packages_paths and match a mapped letter drive on the local computer.

But yes, maybe we could actually fix this in another way.

[OlivierArgentieri]

Hi !

Do you have any update on this ?
Because this issue still exist in the new version of rez (tested with 3.0.0)

Thank you !

[maxnbk]

I think based on #1438 we should try to see if the solution proposed in TSC at the time is the correct step to take. I would prefer a configration-less solution if possible. I am going to start tinkering with this issue to see the effects of replacing the realpath calls and try to start to figure out what sort of testing might be needed.