Too similar file names on macos

[glatterf42]

As pointed out by @measrainsey last year and now by @ravitby, this repository currently contains both demand.csv.gz and DEMAND.csv.gz in data/test/MESSAGEix-GLOBIOM_1.1_R11_no-policy_baseline. This seems to cause git conflicts on macos systems as they don't distinguish between capitalized and non-capitalized file names.

I'm not immediately sure how we can remedy this, possibly by renaming a file, but I'm not sure if the exact names are somehow important (e.g., correspond to some model parameter and need to be exactly the way they are for the file to be found).

[glatterf42]

Thanks for the additional input. Searching for this error message, I came across this suggestion to set up a new, case-sensitive volume on macos that can host the existing code.
However, I'd consider it more elegant if we could avoid using the same name for these files. I hope @khaeru knows if such an adaptation is straightforward.

[glatterf42]

There's also a git config variable that we could play around with to see if some setting satisfies our needs locally.

[khaeru]

This is an unfortunate consequence of the fact that the MESSAGE GAMS code uses both a parameter named demand and a variable named DEMAND. See:
https://github.com/iiasa/message_ix/blob/693f2273eaf31aec7a9938f65ee26f98be967742/message_ix/model/MESSAGE/parameter_def.gms#L147-L159
https://github.com/iiasa/message_ix/blob/693f2273eaf31aec7a9938f65ee26f98be967742/message_ix/model/MESSAGE/data_load.gms#L75-L76
https://github.com/iiasa/message_ix/blob/693f2273eaf31aec7a9938f65ee26f98be967742/message_ix/model/MESSAGE/model_core.gms#L149-L151

The model data snapshot published on Zenodo contains data for both, and so the 'exploded' or 'unpacked' version of that file stored in this repo has both.

AFAIK, the variable DEMAND (upper case) is not relied on by any tests, currently, so I think as a mitigation the corresponding file could be safely deleted. If/when we add or migrate (from message_data) code that relies on data in this variable, we would need to find a different approach.

[measrainsey]

Hi all, thanks for addressing this. I think I'm the source of the issue because I'm a macOS user 🥲 Like @glatterf42 said, my computer does not allow me to have files with the same spelling/name (even if they have different capitalizations). I've tried to deal with this a few times while working on my PR in message-ix-models, such as when I tried to add back the DEMAND file (in b761a93), only to later have to delete it again (in 23ae6ff). So currently no real fix on my end.

[glatterf42]

I think we can leave this open since the merged mitigation PR is likely just a temporary fix; however, for the time being, this issue should be solved on main :)