77a72ecd38
## Summary
This PR fixes the bug where the formatter would format an f-string and
could potentially change the AST.
For a triple-quoted f-string, the element can't be formatted into
multiline if it has a format specifier because otherwise the newline
would be treated as part of the format specifier.
Given the following f-string:
```python
f"""aaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbb ccccccccccc {
variable:.3f} ddddddddddddddd eeeeeeee"""
```
The formatter sees that the f-string is already multiline so it assumes
that it can contain line breaks i.e., broken into multiple lines. But,
in this specific case we can't format it as:
```python
f"""aaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbb ccccccccccc {
variable:.3f
} ddddddddddddddd eeeeeeee"""
```
Because the format specifier string would become ".3f\n", which is not
the original string (`.3f`).
If the original source code already contained a newline, they'll be
preserved. For example:
```python
f"""aaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbb ccccccccccc {
variable:.3f
} ddddddddddddddd eeeeeeee"""
```
The above will be formatted as:
```py
f"""aaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbb ccccccccccc {variable:.3f
} ddddddddddddddd eeeeeeee"""
```
Note that the newline after `.3f` is part of the format specifier which
needs to be preserved.
The Python version is irrelevant in this case.
fixes: #10040
## Test Plan
Add some test cases to verify this behavior.
|
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|---|---|---|
| .. | ||
| resources/test/fixtures | ||
| src | ||
| tests | ||
| Cargo.toml | ||
| CONTRIBUTING.md | ||
| generate.py | ||
| orphan_rules_in_the_formatter.svg | ||
| README.md | ||
| shrink_formatter_errors.py | ||
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.