Add the altair package

[joelostblom]

Description

This adds the altair packages and closes #4579. I wasn't sure what tests would be appropriate, it seems like some package like mpl, pandas, etc tests very specific things whereas others such as shapely, bokeh, statsmodels, etc keep it more minimal. I started minimal for now but happy to add more if there are issues.

I couldn't test the actual graphical output via console.html and when I tried saving to a file via chart.save('chart.html') no errors were raised but I couldn't find the file anywhere (maybe it is saved to a temporary/virtual filesystem in the browser?).

Checklists

• Add a CHANGELOG entry
• Add / update tests
• Add new / update outdated documentation

[hoodmane]

Thanks @joelostblom looks good to me.

[hoodmane]

CI looks good so I'll go ahead and merge this.

[hoodmane]

it seems like some package like mpl, pandas, etc tests very specific things whereas others such as shapely, bokeh, statsmodels, etc keep it more minimal. I started minimal for now but happy to add more if there are issues.

That's generally the way we work. Once upon a time a bunch of pandas things were broken, but we upstreamed all the patches and it hasn't caused any trouble in a long time =D

[joelostblom]

Great, thanks @hoodmane ! One last thing to note is that some of the dependencies to altair have a version restriction (e.g. pandas >= 0.25), but I didn't find a way to add that in the meta.yaml and when I looked at other packages, it seems like they don't specify version restriction although their conda feedstock recipes indicate specific versions (e.g. statsmodels conda feedstock vs pyodide yaml)

[hoodmane]

Yeah we only have one version of each package. We currently don't check constraints and just pray that nothing goes wrong. But there would be an easy way to validate the collection of versions, see #4570.

[hoodmane]

@joelostblom CI looks good, should I merge?

[joelostblom]

Yes, merge away! There is nothing else from my side I believe, and it seems to be working as it should based on my testing console.html (except for the note about not finding the saved file in my original comment).

[hoodmane]

For that, see:
https://pyodide.org/en/latest/usage/accessing-files.html
https://pyodide.org/en/latest/usage/file-system.html#experimental-using-the-native-file-system-in-the-browser

[hoodmane]

Thanks @joelostblom!