CameraHandler::camera question

[dj-mcg]

Hi folks,

Is it still legal to return nullptr from a CameraHandler::camera function? We have a local change we made for Pixar-specific logic in UsdCameraHandler::camera that worked in Maya2023/UFE3 but crashs in Maya2024/UFE4 with the following stack:

  /dist/sw/maya/2024.update2/lib/libShared.so(+0x5ab3d4) [0x7f79e0da83d4]
  /dist/sw/maya/2024.update2/lib/libCommandEngine.so(+0x94431) [0x7f79dcdd9431]
  /dist/sw/maya/2024.update2/lib/libCommandEngine.so(+0xbd5f2) [0x7f79dce025f2]
  /dist/sw/maya/2024.update2/lib/libCommandEngine.so(+0xbce19) [0x7f79dce01e19]
  /dist/sw/maya/2024.update2/lib/libCommandEngine.so(+0xdfb73) [0x7f79dce24b73]
  /dist/sw/maya/2024.update2/lib/libCommandEngine.so(+0xbce19) [0x7f79dce01e19]
  /dist/sw/maya/2024.update2/lib/libCommandEngine.so(+0xbcfe1) [0x7f79dce01fe1]
  SophiaExecutable::evaluate(void*)
  TcommandEngine::executeCommand(Tstring const&, bool, bool, TmelCmdResult*, unsigned int)
  TscriptActionMixin::execute(Tevent const&, std::unique_ptr<TinterpreterResult, std::default_delete<TinterpreterResult> >*)
  TmenuScriptAction::doIt(Tevent const&)
  Taction::performAction(Tevent const&, char const*)
  Taction::doIt()
  /dist/sw/maya/2024.update2/lib/libQt5Core.so.5(+0x2e0f4d) [0x7f79da42af4d]
  /dist/sw/maya/2024.update2/lib/libQt5Core.so.5(+0x2e0f4d) [0x7f79da42af4d]
  /dist/sw/maya/2024.update2/lib/libQt5Widgets.so.5(+0x2dd016) [0x7f79db77a016]
  QMenu::popup(QPoint const&, QAction*)
  QMenu::internalDelayedPopup()
  QObject::event(QEvent*)```

Thanks for any insight you can provide!

[dj-mcg]

FYI, the local change I mentioned was made according to the suggestion we received here:
#2008

It looks like perhaps nullptr is no longer a valid return value from Ufe::CameraHandler::camera(). I moved our check into the find function, skipping any camera that fails our local conditional, and that seems to do the trick without crashing. Is this the new approach? If so, it may be good to update the UFE 4.2 documentation for the camera function.

[dj-mcg]

FWIW I upgraded this to an "Issue"
#4133