Unable to get all USD stages from mayaUsd.lib.StageCache

[BigRoy]

Describe the bug

When running this code:

import mayaUsd
cache = mayaUsd.lib.StageCache.Get(True, True)
stages = cache.GetAllStages()
print(stages)

I get an empty list; no matter whether I have active mayaUsdProxyShape instances in my scene or not.
However, asking around on ASWF slack wg-usd channel others were able make this work.

In their case, maya 2024.0 + maya usd 0.23.0, getting wit the same code e.g. the following result :

[Usd.Stage.Open(rootLayer=Sdf.Find('anon:000001A25196DE40:anonymousLayer1'), sessionLayer=Sdf.Find('anon:000001A25196D1E0:anonymousLayer1-session.usda'), pathResolverContext=Ar.ResolverContext(Ar.DefaultResolverContext())), Usd.Stage.Open(rootLayer=Sdf.Find('d:/588/scene.usda'), sessionLayer=Sdf.Find('anon:000001A25196E680:scene-session.usda'), pathResolverContext=Ar.ResolverContext(Ar.DefaultResolverContext(['D:\\588\\'])))]

Is this a regression?

Steps to reproduce
Steps to reproduce the behavior:

1. Launch Maya
2. Create some proxies
3. Run the example code

Expected behavior

Be able to retrieve any of the current session's Usd.Stage from the cache.
I expect the code snippet to list all used stages by Maya's plugin.

Specs (if applicable):

• OS & version: Windows 10
• Maya version: 2024.2
• Maya USD commit: 0.26.0 (release)

Additional context

I'm not entirely sure whether this cache is intended to be accessible, but since others did get output in an older version I figured it'd be good to report that I was unable to get any results from it.

[pierrebai-adsk]

I think it comes down to a change in our internal implementation. You now have to passs False, True to get the cache:

import mayaUsd
cache = mayaUsd.lib.StageCache.Get(False, True)
stages = cache.GetAllStages()
print(stages)

[BigRoy]

I think it comes down to a change in our internal implementation. You now have to passs False, True to get the cache:

import mayaUsd
cache = mayaUsd.lib.StageCache.Get(False, True)
stages = cache.GetAllStages()
print(stages)

This does indeed work.