Add attr and name to idata

[percygautam]

Description

Related to the discussion being held in the channel.

Checklist

• Follows official PR format
• Includes a sample plot to visually illustrate the changes (only for plot-related functions)
• New features are properly documented (with an example if appropriate)?
• Includes new or updated tests to cover the new feature
• Code style correct (follows pylint and black guidelines)
• Changes are listed in changelog

[percygautam]

How these changes are incorporated in concat. Also, please briefly explain the name attribute?

[ahartikainen]

For concat, either we make everything a list or list only when needed, same for name.

idata1.attrs["a"] = 1
idata2.attrs["a"] = 1

-> idata["a"] == [1, 1] or idata["a"] == 1

idata1.attrs["a"] = 1
idata2.attrs["a"] = 2

-> idata["a"] == [1, 2]

[ahartikainen]

I think that might be the simplest option?

[percygautam]

I have added attrs to concat as suggested. I was modifying from_dict to include attrs, but it already contains attrs argument, that point to dataset.attrs. Should I change already existing attrs to dataset_attrs? Or something else?

[ahartikainen]

I think attrs in from_dict should point to the main attrs (this what you add right now)

[percygautam]

Will this not change the existing API? Also, if we do so, what should the attrs be named? (Maybe group_attrs or dataset_attrs?)

[ahartikainen]

I think existing api is not yet released?

That sounds a good idea.

We could also add kwargs for from_dict and then get attrs for each group if needed?

So attrs could then mean the idata attrs. And each group might have {groupname}_attrs?

[OriolAbril]

Another question is whether we should modify current code to store arviz/ppl version... as idata attrs instead of repeating them in every group.

[ahartikainen]

Do we want to get this in the next release?

[codecov]

Codecov Report

Merging #1357 (fd5c4c4) into main (b54e022) will decrease coverage by 0.04%.
The diff coverage is 93.54%.

@@            Coverage Diff             @@
##             main    #1357      +/-   ##
==========================================
- Coverage   90.90%   90.85%   -0.05%     
==========================================
  Files         113      113              
  Lines       12217    12274      +57     
==========================================
+ Hits        11106    11152      +46     
- Misses       1111     1122      +11     

Impacted Files	Coverage Δ
arviz/data/inference_data.py	83.02% <88.23%> (-0.53%)	⬇️
arviz/data/io_dict.py	94.07% <100.00%> (+0.68%)	⬆️

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[ahartikainen]

This PR can wait to next release. It will change many io functions.