[ideas] when callr_function != NULL and debug != NULL, targets should return error

[stemangiola]

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Description

I cannot see any use case where I would like to have callr_function != NULL and debug != NULL.

When this happens accidentally (I forget to update the pipeline), the error due to side effects is not apparent, and this costs me long minutes to debug.

Should targets throw error if callr_function != NULL and debug != NULL?

[wlandau]

The case for callr_function != NULL and debug != NULL is not very common, but it could happen. You might have a generally error-prone target and may want to leave the debug option as is so you can easily return to it when callr_function is NULL. Otherwise, you might find yourself repeatedly commenting and uncommenting the debug option. So I would rather not go out of our way to throw an error in that case.

[stemangiola]

Thanks, just as a confirmation, if the debug is on, but the callr_function != NULL, does the debug get ignored, and is side effect free?

[wlandau]

Yes, under those conditions the debug option is ignored harmlessly.