Specify version of plotly.js in CDN URL

[adehad]

Summary of Changes

1. To prevent version changes of plotly.js breaking old html exports, these exports now included a version URL that matches plotly.py's bundled plotly.js. This is the default behaviour of include_plotlyjs='cdn'.
2. include_plotlyjs='cdn-latest' added to preserve original behaviour.
3. Refactored tests and code that rely on the plotly.js URL to use a function in io/_utils.py

Code PR

• I have read through the contributing notes and understand the structure of the package. In particular, if my PR modifies code of plotly.graph_objects, my modifications concern the codegen files and not generated files.
• I have added tests (if submitting a new feature or correcting a bug) or
  modified existing tests.
• For a new feature, I have added documentation examples in an existing or
  new tutorial notebook (please see the doc checklist as well). Not Applicable
• I have added a CHANGELOG entry if fixing/changing/adding anything substantial.
• For a new feature or a change in behaviour, I have updated the relevant docstrings in the code to describe the feature or behaviour (please see the doc checklist as well).

[nicolaskruchten]

Thanks for this PR! I'll take a look very soon.

I'm curious: was there a recent breaking change that affected you? We work very hard to avoid those so we'd like to know if something cropped up!

[adehad]

I'm curious: was there a recent breaking change that affected you? We work very hard to avoid those so we'd like to know if something cropped up!

Indeed, last week had some trouble with some historical px.treemap() made figures. These treemaps were generated using a pandas DataFrame and then specifying a path.

Tracked it down to the v1.58.0 release from a console message suggesting something along the lines of "root could not be found". (Which confused me at the time as my path included a "root" too haha!)

Thanks for this PR! I'll take a look very soon.

Appreciate it ! Looks like I broke the docs, not too familiar with this set up, but happy to have a crack if you have any pointers.

Example failure for 3d-axes :

[NbConvertApp] Converting notebook build/ipynb/3d-axes.ipynb to html
[NbConvertApp] Executing notebook with kernel: python3
Traceback (most recent call last):
  File "/home/circleci/project/doc/venv/bin/jupyter-nbconvert", line 8, in <module>
    sys.exit(main())
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/jupyter_core/application.py", line 254, in launch_instance
    return super(JupyterApp, cls).launch_instance(argv=argv, **kwargs)
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/traitlets/config/application.py", line 845, in launch_instance
    app.start()
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/nbconvert/nbconvertapp.py", line 350, in start
    self.convert_notebooks()
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/nbconvert/nbconvertapp.py", line 524, in convert_notebooks
    self.convert_single_notebook(notebook_filename)
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/nbconvert/nbconvertapp.py", line 489, in convert_single_notebook
    output, resources = self.export_single_notebook(notebook_filename, resources, input_buffer=input_buffer)
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/nbconvert/nbconvertapp.py", line 418, in export_single_notebook
    output, resources = self.exporter.from_filename(notebook_filename, resources=resources)
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/nbconvert/exporters/exporter.py", line 181, in from_filename
    return self.from_file(f, resources=resources, **kw)
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/nbconvert/exporters/exporter.py", line 199, in from_file
    return self.from_notebook_node(nbformat.read(file_stream, as_version=4), resources=resources, **kw)
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/nbconvert/exporters/html.py", line 119, in from_notebook_node
    return super().from_notebook_node(nb, resources, **kw)
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/nbconvert/exporters/templateexporter.py", line 384, in from_notebook_node
    output = self.template.render(nb=nb_copy, resources=resources)
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/jinja2/environment.py", line 1090, in render
    self.environment.handle_exception()
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/jinja2/environment.py", line 832, in handle_exception
    reraise(*rewrite_traceback_stack(source=source))
  File "/home/circleci/project/doc/venv/lib/python3.7/site-packages/jinja2/_compat.py", line 28, in reraise
    raise value.with_traceback(tb)
  File "/home/circleci/project/doc/nb.tpl", line 1, in top-level template code
    {%- extends 'basic.tpl' -%}
jinja2.exceptions.TemplateNotFound: basic.tpl

[nicolaskruchten]

Ah, sorry for the breakage of the treemaps! if you're able to share with us an example, we'd love to fix it for other users!!

Re the docs in CI, don't worry about that for now, it's unrelated to your PR.

[nicolaskruchten]

Ah, i've found an example of this breakage in our very own docs 🙈 and I've filed an upstream issue: plotly/plotly.js#5328

[nicolaskruchten]

(your PR is still a good idea and we'll try to merge it soon!)

[adehad]

if you're able to share with us an example, we'd love to fix it for other users!!

Yep completely right, slipped my mind that this would affect all users of of plotly.py especially as 4.14.0 now uses plotly.js 1.58.1.

I've been able to reproduce it with an example from the docs:

import plotly.express as px
import pandas as pd
vendors = ["A", "B", "C", "D", None, "E", "F", "G", "H", None]
sectors = ["Tech", "Tech", "Finance", "Finance", "Other",
           "Tech", "Tech", "Finance", "Finance", "Other"]
regions = ["North", "North", "North", "North", "North",
           "South", "South", "South", "South", "South"]
sales = [1, 3, 2, 4, 1, 2, 2, 1, 4, 1]
df = pd.DataFrame(
    dict(vendors=vendors, sectors=sectors, regions=regions, sales=sales)
)
df["all"] = "all" # in order to have a single root node
print(df)
fig = px.treemap(df, path=['all', 'regions', 'sectors', 'vendors'], values='sales')
fig.show()

Console Error I see is:
Uncaught TypeError: can't access property "root", e.trace is undefined
(Edit looks like I was a bit slow and you got this already whoops !)

[nicolaskruchten]

Thanks! We've fixed this particular bug in 1.58.2 BTW.

[adehad]

Note, if this is merged after #3030 - i.e. use j2 v2, this call should be changed to:

Suggested change

	cdn_url = plotly_cdn_url(cdn_ver="latest")
	cdn_url = plotly_cdn_url(cdn_ver="latest-v2")

See: plotly/plotly.js#5462

[nicolaskruchten]

OK, going to merge this and then do a 5.0 beta release :)

I actually think I will drop the latest option, as ideally we won't be hosting a "latest" bundle on the CDN for v2 after all, to discourage folks baking it into their production systems.

[adehad]

No idea if you needed extra permissions (I think I allowed "Maintainers" to contribute to the branch) but I've also just "invited you to collaborate" on the fork, feel free to push directly to it!

[nicolaskruchten]

Thanks! I think I pushed up a branch to your repo by mistake instead of appending to this one... sorry :)

Thanks again for the contribution! I'll remove the "latest" functionality in a second PR.