nb_execution_mode=auto should take into account cells with no expected output

[bsipocz]

Describe the bug

context and expectation
When I use nb_execution_mode=auto I would expect that execution is skipped when all the code cells are run.

bug
But instead the execution is always run.

problem
This is because some of the cells

• produces no output, even though they are run. E.g. see the first code cell here, which contains imports: https://github.com/NASA-NAVO/navo-workshop/blob/main/CS_Catalog_Queries.ipynb
• accidentally remained empty cells
• or maybe cells with commented out code only (especially in the case of tutorial exercise notebooks)

I think none of these cases should trigger the execution.

I'm happy to propose a fix in a PR

Reproduce the bug

Run all the cells in the notebook referenced above, save it. Then run sphinx-build -b html -D nb_execution_mode=auto . _build/html on it

List your environment

No response

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[chrisjsewell]

Heya, yeh happy to see proposals/suggestions thanks 👍

I'd note an alternative solution though, now we have file-level configuration: https://myst-nb.readthedocs.io/en/latest/configuration.html#file-level-configuration

if you want certain notebooks executed and others not, you could set globally nb_execution_mode="force", then set per-notebook:

{
  "metadata": {
    "mystnb": {
      "execution_mode": "off"
    }
  }
}

or visa-versa

[bsipocz]

Yes, I think that will be a good solution for some of the projects I maintain (e.g. where I definitely want to keep the outputs as they are, e.g. when they are a product of cells with a long run time), but the auto option promises such a nice, low maintenance middle-ground.

[fzimmermann89]

We have a similar issue: A lot of cells in our notebooks do not produce any output.
The notebooks are automatically created and are either fresh without any outputs, or up to date.

This, we would like a "lazy" option: Instead of running if any output is missing, run if no output exists.