Read user configuration from `~/.config/ruff/ruff.toml` on macOS

[charliermarsh]

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Summary

This PR moves Ruff's user-specific configuration from ~/Library/Application Support/ruff/ruff.toml to ~/.config/ruff/ruff.toml.

Many other tools do this. On my machine alone: dagger, zed, gatsby, gh, wandb, etc.

I also polled Twitter and it won in a landslide:

Let's ship this in v0.5.0, along with a deprecation warning (so we'll continue to respect ~/Library/Application Support/ruff/ruff.toml, but log a warning).

Closes https://github.com/astral-sh/ruff/issues/10739.

Test Plan

• Created a file with an unused import.
• Ran cargo check foo.py.
• Verified that the deprecated configuration was loaded and respected, with a warning:

warning: Reading configuration from `~/Library/Application Support` is deprecated. Please move your configuration to `/Users/crmarsh/.config/ruff/ruff/ruff.toml`.
[2024-04-23][16:09:10][ruff::resolve][DEBUG] Using configuration file (via cwd) at: /Users/crmarsh/Library/Application Support/ruff/ruff.toml

• Created ~/.config/ruff/ruff.toml.
• Verified that the new configuration was loaded:

[2024-04-23][16:10:23][ruff::resolve][DEBUG] Using configuration file (via cwd) at: /Users/crmarsh/.config/ruff/ruff.toml

[github-actions[bot]]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

Formatter (stable)

✅ ecosystem check detected no format changes.

Formatter (preview)

✅ ecosystem check detected no format changes.

[MichaReiser]

Sooo, we're doing twitter driven development now :joy:

[konstin]

I would change the reasoning/description: Follow the XDG specification on all Unix platforms. Ruff will now use the XDG config directory to read user-level configuration (default: ~/.config/ruff/ruff.toml) over Library/Application Support/ruff/ruff.toml on macOS.

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #11115 will degrade performances by 4.69%

_{Comparing charlie/xdg (c4d143a) with ruff-0.5 (9348821)}

Summary

❌ 1 regressions ✅ 29 untouched benchmarks

:warning: Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	ruff-0.5	charlie/xdg	Change
❌	linter/default-rules[pydantic/types.py]	1.8 ms	1.9 ms	-4.69%

[MichaReiser]

I ran through the test plan and verified the deprecation message.