Update save.py to use utf-8 instead of None per default

[franzhaas]

I experience issues with the Null on windows. It appears as if when saving HTML, the template is already utf-8 and when writing the files with the system default code page, there are encoding issues.

Alternatively I see another options to solve my problem.:

set it only in the

elif format == "html":

branch...

[jonmmease]

Thanks for the contribution @franzhaas. Setting the default encoding to utf-8 when saving our text-based formats (svg and html) makes sense. The tests are failing because it's not valid to set an encoding when saving to binary formats (png and pdf).

So I think you'll need to move the default encoding up a level and set it for only the svg and html branches.

[franzhaas]

I think it's now ok.

...I need to get into the habit of using my account to run CI...

[jonmmease]

Thanks @franzhaas,

While reviewing, I noticed that for svg and vega formats, we look for an encoding kwarg and then fall back to utf-8 if it's not present. I think this makes sense for json and html formats as well. I added suggestions, so I added review suggestions that make this change.

Not a requirement for this PR, but it would be good to add encoding as an explicit argument to save with a default value of utf-8 and add it to the docstring. Right now it's basically a secret keyword argument.

for consistence with svg export, I added suggestions to honor an encoding argument passed into the function

[franzhaas]

I think it is ok now...

I personally would prefer to not have the encoding parameter explicit, working by default and the ability to pass an IO object when specific encodings are necessary appear to be a good and compact solution too me.

[jonmmease]

Thanks @franzhaas, one last formatting fix needed to get the tests passing and this is good to go!

Edit: sorry, I posted and deleted a comment here that was meant for another thread

[franzhaas]

I am a bit confused about that one... I cant remember to have touched this file... and i see nothing in the logs... also it didn't trigger on my own CI run...

but sure i fixed it...

[jonmmease]

Thanks! Maybe ruff released an update.