recipe_ocean_bgc.yml fails in volume_statistics preprocessor

[schlunma]

Describe the bug
While testing ESMValGroup/ESMValCore#1429 I found that recipe_ocean_bgc.yml fails (using the current main branches of ESMValTool and ESMValCore):

Traceback (most recent call last):
  File "/mnt/lustre02/work/bd0854/b309141/mambaforge/envs/esm/lib/python3.9/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
  File "/mnt/lustre02/work/bd0854/b309141/repos/ESMValCore/esmvalcore/_task.py", line 780, in _run_task
    output_files = task.run()
  File "/mnt/lustre02/work/bd0854/b309141/repos/ESMValCore/esmvalcore/_task.py", line 253, in run
    self.output_files = self._run(input_files)
  File "/mnt/lustre02/work/bd0854/b309141/repos/ESMValCore/esmvalcore/preprocessor/__init__.py", line 547, in _run
    product.apply(step, self.debug)
  File "/mnt/lustre02/work/bd0854/b309141/repos/ESMValCore/esmvalcore/preprocessor/__init__.py", line 407, in apply
    self.cubes = preprocess(self.cubes, step,
  File "/mnt/lustre02/work/bd0854/b309141/repos/ESMValCore/esmvalcore/preprocessor/__init__.py", line 342, in preprocess
    result.append(_run_preproc_function(function, item, settings,
  File "/mnt/lustre02/work/bd0854/b309141/repos/ESMValCore/esmvalcore/preprocessor/__init__.py", line 298, in _run_preproc_function
    return function(items, **kwargs)
  File "/mnt/lustre02/work/bd0854/b309141/repos/ESMValCore/esmvalcore/preprocessor/_volume.py", line 203, in volume_statistics
    t_dim = cube.coord_dims('time')[0]
IndexError: tuple index out of range

Please attach

• https://github.com/ESMValGroup/ESMValTool/blob/main/esmvaltool/recipes/recipe_ocean_bgc.yml
• main_log_debug.txt

[valeriupredoi]

also of interest and related to this recipe #2336

[remi-kazeroni]

Note that this recipe ran successfully when we tested all recipes for the release of v2.4: https://esmvaltool.dkrz.de/shared/esmvaltool/v2.4.0-test3/ When I first opened #2336, the automatic download option was not available. Using that option made it possible to test the recipe successfully for the past release. But looking at the main_log_debug.txt file posted by @schlunma, it looks like automatic download option was used here as well. Could the problem be related to a recent change in the Core?

[schlunma]

Ha! This was fixed by ESMValGroup/ESMValCore#1497 🎉

The recipe still fails, but only in the diagnostic. I will move this discussion to #2336.