Give Pyright what it wants (alias attributes everywhere)

[A5rocks]

I don't like pyright nor this behavior, but that doesn't mean users should have to care. We can add a test to prevent any sort of regression regarding this, forever.

cc @mikenerone cause this is from Gitter.

also @CoolCat467 I ran into issues with running the regenerate-files pre-commit hook and couldn't figure them out after about 15 minutes. It was complaining about attrs not being possible to import but unfortunately there's no way to get it to use the test-requirements.txt file. Have you run into this issue regarding it not picking up the virtual environment? (I'm using a seperate git client so that kind of makes sense, but now's the first time I ran into this...)

[codecov]

Codecov Report

Attention: Patch coverage is 90.47619% with 2 lines in your changes missing coverage. Please review.

Project coverage is 99.71%. Comparing base (8850705) to head (ff487e2).
Report is 122 commits behind head on main.

Files with missing lines	Patch %	Lines
src/trio/_tests/test_exports.py	86.66%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3114      +/-   ##
==========================================
+ Coverage   99.58%   99.71%   +0.12%     
==========================================
  Files         121      122       +1     
  Lines       18157    23660    +5503     
  Branches     3272     4037     +765     
==========================================
+ Hits        18082    23592    +5510     
+ Misses         52       48       -4     
+ Partials       23       20       -3     

Files with missing lines	Coverage Δ
src/trio/_core/_local.py	100.00% <100.00%> (ø)
src/trio/_core/_run.py	99.40% <100.00%> (+0.37%)	⬆️
src/trio/_tests/test_exports.py	99.05% <86.66%> (-0.57%)	⬇️

... and 51 files with indirect coverage changes

[jakkdl]

this makes me want to write a linter rule, but also feels ridiculous (and idk which flake8 plugin it would fit) to write an attrs+pyright-specific rule.

How slow/fast is the test? If it's anything but trivial I could rewrite it as an ast visitor.

[A5rocks]

this makes me want to write a linter rule, but also feels ridiculous (and idk which flake8 plugin it would fit) to write an attrs+pyright-specific rule.

How slow/fast is the test? If it's anything but trivial I could rewrite it as an ast visitor.

Yeah lint rule would make more sense but unfortunately a lint rule would miss context that's helpful (like whether a class is exported).

It takes 1.75 seconds to run locally, though that's with the overhead of starting pytest.

[CoolCat467]

Alias changes make sense and test looks like it would work pretty well but didn't look into the details super closely, but general idea of it seems solid.

If test is slow, do we need to mark it with @slow or something?

[A5rocks]

If test is slow, do we need to mark it with @slow or something?

Maybe? Here's the output at the end of pytest --durations=10 locally:

================================================ slowest 10 durations =================================================
3.66s call     src/trio/_tests/tools/test_gen_exports.py::test_process[from collections import Counter\n]
2.73s call     src/trio/_tests/tools/test_gen_exports.py::test_process[from collections import Counter\nimport os\n]
2.53s call     src/trio/_tests/tools/test_gen_exports.py::test_process[from typing import TYPE_CHECKING\nif TYPE_CHECKING:\n    from collections import Counter\n]
2.11s call     src/trio/_tests/test_socket.py::test_many_sockets
2.05s call     src/trio/_tests/test_socket.py::test_SocketType_connect_paths
2.04s call     src/trio/_tests/test_socket.py::test_address_in_socket_error
2.02s call     src/trio/_tests/test_highlevel_open_tcp_listeners.py::test_open_tcp_listeners_ipv6_v6only
1.73s call     src/trio/_tests/test_exports.py::test_pyright_recognizes_init_attributes
0.65s call     src/trio/_tests/test_exports.py::test_static_tool_sees_all_symbols[jedi-trio]
0.41s call     src/trio/_tests/tools/test_gen_exports.py::test_lint_failure

I don't think it's an appreciable slowdown. Maybe it's a good idea to put @slow on everything over 1 second? I can probably write the test to be faster (by not rescanning the tokenizations, not including tests in the glob). Actually I'll do just that.

EDIT: just the second optimization there changed it to 0.64s locally, so I think it's fine if not marked @slow.

[jakkdl]

maybe also good to add a comment or two on what this token thing is doing, I find it hard to understand at a glance what the code is doing.

[jakkdl]

if you declare end_offset outside the loop I think the warning goes away (and makes the code easier to read).

codecov wants a pragma: no branch on the loop to hit 100%

[A5rocks]

Unfortunately the warning doesn't go away; it does make the code more correct (previously it didn't handle start==len(file)-1, I think)

[CoolCat467]

I think with the zero-initialization now that should be good

[jakkdl]

This is fairly gnarly to fix in an AST visitor, I don't see any way of doing it that's not overkill, but I think you could open an issue for ruff and see if they have a decent way of getting at it.

[TeamSpen210]

There’s another approach we could use, but it’d might require starting an additional interpreter. Run a script which monkeypatches attrs.field to store whether alias was set into the metadata dict, import trio, then we can just loop through fields.

Unsure if that’d be faster though. We could avoid the new interpreter if the monkeypatch was done before any tests import trio, but that means it affects all tests. Probably not too much of an issue since metadata does nothing, and just wrapping the function should be fairly safe.

[A5rocks]

There’s another approach we could use, but it’d might require starting an additional interpreter. Run a script which monkeypatches attrs.field to store whether alias was set into the metadata dict, import trio, then we can just loop through fields.

Unsure if that’d be faster though. We could avoid the new interpreter if the monkeypatch was done before any tests import trio, but that means it affects all tests. Probably not too much of an issue since metadata does nothing, and just wrapping the function should be fairly safe.

It's not significantly faster:

(.venv) PS C:\Users\A5rocks\Documents\trio> hyperfine 'python -c \"import trio\"'
Benchmark 1: python -c "import trio"
  Time (mean ± σ):     410.5 ms ±  14.2 ms    [User: 45.3 ms, System: 22.9 ms]
  Range (min … max):   390.3 ms … 435.0 ms    10 runs

I think the main improvement would be that it's slightly more reliable. It sounds annoying to implement though.

[A5rocks]

@TeamSpen210 do you have any implementation ideas for your idea?

I was thinking about it just for the gain in reliability, but I think we would then get a flakey test because we delete and reimport trio to get all the warnings. I guess it's fine if we just patch attrs cause then the reimport will still be using the patched attrs?

[TeamSpen210]

Pushed an implementation using monkeypatching here. Unfortunately a downside I realised is that the monkeypatching code has to be either outside the trio package, or directly in __init__ before any other imports. So either this test can't be run by people just installing the package, or we'll have to have a module outside there. I could set it up to just skip if the monkeypatch "plugin" isn't specified though.

[Zac-HD]

I do like the "monkeypatch, and skip that test if not monkeypatched" plan 🙂

[Zac-HD]

@TeamSpen210 @A5rocks I'd really like to get this merged so I can use it; is there anything I can do to help?

[A5rocks]

@TeamSpen210 @A5rocks I'd really like to get this merged so I can use it; is there anything I can do to help?

Nope! I've just been pushing off working on some trio stuff for a bit, I'll incorporate better testing strategy soon:tm: (probably just using our already created pytest plugin nvm I forgot we can't + copy.copy() of the kwargs instead of picking and choosing. Everything else sounds fine)

[TeamSpen210]

Would you like me to make the monkeypatch approach a competing PR, or PR to yours, or do you want to stick with the current approach?

[A5rocks]

If you wouldn't mind, you should be able to commit to this PR.

[TeamSpen210]

Committed, didn't want to do big changes to other people's PRs without permission. Though it is easy to revert so probably that's fine.

[A5rocks]

Should we move the plugin to the (adjacent to src) tests directory or something? Having it in src feels weird...

[TeamSpen210]

That should work, if it's in sys.path so pytest can import.