Pin PyScript

[rmartin16]

Changes

• PyScript deprecated latest and requires pinning for newer versions
• <py-script> can just be <script type="py"> now
• PyScript now enables a top-level loop by default; I added async="false" to disable it
• <py-config> isn't necessary since it can be specified via <script type="py" config="pyscript.toml">

Notes

• I think that ideally the PyScript version would live in Briefcase...or via the method I'm working on in Move logic to determine support revision from templates briefcase#1943. But I'll leave that to future work I think
• I can't figure out a good method to stop Toga's warnings from showing in the page content
  • Although, adding import warnings; warnings.filterwarnings("ignore") to index.html technically works....

BRIEFCASE_REPO: https://github.com/mhsmith/briefcase
BRIEFCASE_REF: pyscript-2024.11.1

PR Checklist:

• All new features have been tested
• All new features have been documented
• I have read the CONTRIBUTING.md file
• I will abide by the code of conduct

[rmartin16]

Also, I'm a bit mystified by PyScript's configuration. For instance, I find the PR where [splashscreen] was apparently added and where autoclose would be implemented in the code....but I can't find any reference to it in the documentation....so, I don't know if this is still valid config. Similarly, I don't know if terminal = false still does anything; they added a terminal attribute for the <script type="py"> tag 🤷🏼‍♂️

[freakboy3742]

Also, I'm a bit mystified by PyScript's configuration. For instance, I find the PR where [splashscreen] was apparently added and where autoclose would be implemented in the code....but I can't find any reference to it in the documentation....so, I don't know if this is still valid config. Similarly, I don't know if terminal = false still does anything; they added a terminal attribute for the <script type="py"> tag 🤷🏼‍♂️

Pyscript has definitely gone through some big changes since I last did a big Toga update; most of those changes have been very welcome (distancing "getting Python working in the browser" from "having opinions about look and feel"). So - the splash screen handling has definitely been removed; and terminal handling has... changed. Part of that seems to be a new default handler for stderr which puts stderr content into the DOM. All documentation says should be possible to disable with plugins = ["!error"]... but this doesn't seem to be working for me. The simple fix is to add a div.py-error { display: none } CSS modification; but that doesn't seem ideal. I've poked PyScript support to get some guidance on this (pyscript/pyscript#2220).

However, we also need to fix some other issues that have slipped in as a result of API updates.

• Button handlers no longer seem to work. Pressing the button on Tutorial 0 doesn't cause anything to appear in the console.
• Style appears to have been lost from dialogs. The about dialog in Tutorial 0 displays in "browser default serif", not the Shoelace sans-serif default.
• We probably need to add a Splash screen, so that we don't get a blank page on load.

On the last point, I'm not sure if that should be a Toga concern or a Briefcase concern - at least for the moment, I suspect it needs to be a Briefcase concern, because Toga can't provide any code that will contribute to the "pre-javascript executing" state of the page. I started looking broadly at this problem in beeware/briefcase#1285; that set of changes would provide a mechanism for a wheel to contribute content to the Briefcase-generated HTML. However, I've been distracted with Py3.13 and getting binary wheels working for the last year, so I haven't been able to give the web backend the attention it needs.

[freakboy3742]

This is definitely a set of changes we should make; but we need to fix the behavior change issues flagged (which might require a Toga change as well to adapt how button handlers are attached)

[rmartin16]

Makes sense :) I rather doubt I will further pursue additional efforts then to bring support back up to date; I am mostly intrigued because PyScript is particularly interesting...but it's also at the edge of a lot of my knowledge. So, I'll leave to your discretion to just close this PR...or possibly expand upon it...whatever this case is fine with me.

[mhsmith]

I've updated to PyScript 2024.11.1, and added a corresponding Briefcase PR to remove the obsolete configuration settings:

• Update to PyScript 2024.11.1 briefcase#2080

• Button handlers no longer seem to work. Pressing the button on Tutorial 0 doesn't cause anything to appear in the console.

It works fine for me in both Chrome and Safari.

• Style appears to have been lost from dialogs. The about dialog in Tutorial 0 displays in "browser default serif", not the Shoelace sans-serif default.

Fixed in beeware/toga#3035.

[freakboy3742]

I've made 2 small changes:

1. I've added an animation throb to the splash screen
2. I've added an initial templated pyscript.toml file that turns on the "official" way to hide error output, rather than a CSS-based approach. This config file will be overwritten by the current mainline Briefcase; but I've updated the Briefcase PR to read-and-rewrite pyscript.toml if it the template provides it. This should allow us to accomodate future pyscript.toml changes without needing a Briefcase change (unless there's a change to the format for packages...)

I'm happy with where this is right now; leaving for @mhsmith to cross-check and merge these changes.

[mhsmith]

In that case, the CSS to hide the stderr should be unnecessary, so I've removed it.