Reduce database queries on dashboards

[eemeli]

Fixes #3545

This should speed things up a bit. Two related changes are included to resolve the identified inefficiencies, and a couple of the Locale methods are dropped/simplified to match current usage. The ProjectLocale.get_latest_activity() function is split into two separate implementations on Locale and Project, as they are now rather different, and the get_object_or_none() utility is dropped as obsolete.

[mathjazz]

I'm getting this error on the locale pages:

[server] [INFO:django.server] 2025-02-11 19:45:53,493 "GET /de/ HTTP/1.1" 200 3956
[server] [ERROR:django.request] 2025-02-11 19:45:54,292 Internal Server Error: /de/ajax/
[server] Traceback (most recent call last):
[server]   File "/usr/local/lib/python3.11/site-packages/django/core/handlers/exception.py", line 55, in inner
[server]     response = get_response(request)
[server]                ^^^^^^^^^^^^^^^^^^^^^
[server]   File "/usr/local/lib/python3.11/site-packages/django/core/handlers/base.py", line 197, in _get_response
[server]     response = wrapped_callback(request, *callback_args, **callback_kwargs)
[server]                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[server]   File "/app/pontoon/base/utils.py", line 84, in wrap
[server]     return f(request, *args, **kwargs)
[server]            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[server]   File "/app/pontoon/teams/views.py", line 135, in ajax_projects
[server]     return render(
[server]            ^^^^^^^
[server]   File "/usr/local/lib/python3.11/site-packages/django/shortcuts.py", line 24, in render
[server]     content = loader.render_to_string(template_name, context, request, using=using)
[server]               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[server]   File "/usr/local/lib/python3.11/site-packages/django/template/loader.py", line 62, in render_to_string
[server]     return template.render(context, request)
[server]            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[server]   File "/usr/local/lib/python3.11/site-packages/django_jinja/backend.py", line 59, in render
[server]     return mark_safe(self._process_template(self.template.render, context, request))
[server]                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[server]   File "/usr/local/lib/python3.11/site-packages/django_jinja/backend.py", line 105, in _process_template
[server]     return handler(context)
[server]            ^^^^^^^^^^^^^^^^
[server]   File "/usr/local/lib/python3.11/site-packages/jinja2/environment.py", line 1304, in render
[server]     self.environment.handle_exception()
[server]   File "/usr/local/lib/python3.11/site-packages/jinja2/environment.py", line 939, in handle_exception
[server]     raise rewrite_traceback_stack(source=source)
[server]   File "/app/pontoon/teams/templates/teams/includes/projects.html", line 28, in top-level template code
[server]     {% set latest_activity = project.get_latest_activity(locale) %}
[server]     ^^^^^^^^^^^^^^^^^^^^^^^^^
[server]   File "/app/pontoon/base/models/project.py", line 293, in get_latest_activity
[server]     if project_locale and project_locale.latest_translation
[server]                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[server] AttributeError: 'list' object has no attribute 'latest_translation'

[eemeli]

I'm getting this error on the locale pages:

Should be fixed now, was a silly mistake.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 53.84615% with 18 lines in your changes missing coverage. Please review.

Project coverage is 78.94%. Comparing base (48ed7e0) to head (decac2f).
Report is 7 commits behind head on main.

Additional details and impacted files

[mathjazz]

Nice work! Tested locally and on stage and performance seems better. I also didn't spot any issues with the stats and latest activity data.

Left some comments inline.

[mathjazz]

Is this really necessary?

[eemeli]

The cast() is a no-op at runtime, but with it the type of project is correct within this function.

[mathjazz]

While I appreciate the intent behind improving type safety, our Python codebase does not use static typing consistently. Introducing it in just this one place creates an inconsistency that might confuse other developers who are not expecting type hints.

[eemeli]

On the other hand, type hints were how I was able to catch the bug fixed in #3562. Without them, working with Pontoon code is much more difficult and more error-prone, in particular for developers not previously familiar with it.

We should be working towards more type hinting being available in Pontoon.

[eemeli]

I got ajax_projects() down to 4 queries for anonymous users, and up to 7 if you're logged in with admin rights. That's probably the best that can be done here easily.

[mathjazz]

Deployed latest version to stage.

[mathjazz]

While I appreciate the intent behind improving type safety, our Python codebase does not use static typing consistently. Introducing it in just this one place creates an inconsistency that might confuse other developers who are not expecting type hints.

[mathjazz]

@flodolo Could you take this for a spin on stage?

[flodolo]

Seems to work fine for me, couldn't find inconsistencies.