ruff/crates/ruff_python_formatter
Dhruv Manilawala f3dac27e9a
Fix f-string formatting in assignment statement (#14454)
## Summary

fixes: #13813

This PR fixes a bug in the formatting assignment statement when the
value is an f-string.

This is resolved by using custom best fit layouts if the f-string is (a)
not already a flat f-string (thus, cannot be multiline) and (b) is not a
multiline string (thus, cannot be flattened). So, it is used in cases
like the following:
```py
aaaaaaaaaaaaaaaaaa = f"testeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee{
    expression}moreeeeeeeeeeeeeeeee"
```
Which is (a) `FStringLayout::Multiline` and (b) not a multiline.

There are various other examples in the PR diff along with additional
explanation and context as code comments.

## Test Plan

Add multiple test cases for various scenarios.
2024-11-26 15:07:18 +05:30
..
resources/test/fixtures Fix f-string formatting in assignment statement (#14454) 2024-11-26 15:07:18 +05:30
src Fix f-string formatting in assignment statement (#14454) 2024-11-26 15:07:18 +05:30
tests Fix f-string formatting in assignment statement (#14454) 2024-11-26 15:07:18 +05:30
Cargo.toml Bump MSRV to Rust 1.80 (#13826) 2024-10-20 10:55:36 +02:00
CONTRIBUTING.md Remove remaining ruff_shrinking references (#11272) 2024-05-03 20:22:08 +00:00
generate.py Normalize implicit concatenated f-string quotes per part (#13539) 2024-10-08 09:59:17 +00:00
orphan_rules_in_the_formatter.svg Generate FormatRule definitions (#4724) 2023-06-01 08:38:53 +02:00
README.md Move deviations from formatter README to documentation (#10444) 2024-03-18 08:22:28 +00:00

Ruff Formatter

The Ruff formatter is an extremely fast Python code formatter that ships as part of the ruff CLI.

Goals

The formatter is designed to be a drop-in replacement for Black, but with an excessive focus on performance and direct integration with Ruff.

Specifically, the formatter is intended to emit near-identical output when run over Black-formatted code. When run over extensive Black-formatted projects like Django and Zulip, > 99.9% of lines are formatted identically. When migrating an existing project from Black to Ruff, you should expect to see a few differences on the margins, but the vast majority of your code should be unchanged.

If you identify deviations in your project, spot-check them against the intentional deviations enumerated below, as well as the unintentional deviations filed in the issue tracker. If you've identified a new deviation, please file an issue.

When run over non-Black-formatted code, the formatter makes some different decisions than Black, and so more deviations should be expected, especially around the treatment of end-of-line comments. For details, see Black compatibility.

Getting started

The Ruff formatter is available as of Ruff v0.1.2. Head to The Ruff Formatter for usage instructions and a comparison to Black.