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]

I've added an initial templated pyscript.toml file that turns on the "official" way to hide error output

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