## Summary
This PR detects the use of PEP 701 f-strings before 3.12. This one
sounded difficult and ended up being pretty easy, so I think there's a
good chance I've over-simplified things. However, from experimenting in
the Python REPL and checking with [pyright], I think this is correct.
pyright actually doesn't even flag the comment case, but Python does.
I also checked pyright's implementation for
[quotes](98dc4469cc/packages/pyright-internal/src/analyzer/checker.ts (L1379-L1398))
and
[escapes](98dc4469cc/packages/pyright-internal/src/analyzer/checker.ts (L1365-L1377))
and think I've approximated how they do it.
Python's error messages also point to the simple approach of these
characters simply not being allowed:
```pycon
Python 3.11.11 (main, Feb 12 2025, 14:51:05) [Clang 19.1.6 ] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> f'''multiline {
... expression # comment
... }'''
File "<stdin>", line 3
}'''
^
SyntaxError: f-string expression part cannot include '#'
>>> f'''{not a line \
... continuation}'''
File "<stdin>", line 2
continuation}'''
^
SyntaxError: f-string expression part cannot include a backslash
>>> f'hello {'world'}'
File "<stdin>", line 1
f'hello {'world'}'
^^^^^
SyntaxError: f-string: expecting '}'
```
And since escapes aren't allowed, I don't think there are any tricky
cases where nested quotes or comments can sneak in.
It's also slightly annoying that the error is repeated for every nested
quote character, but that also mirrors pyright, although they highlight
the whole nested string, which is a little nicer. However, their check
is in the analysis phase, so I don't think we have such easy access to
the quoted range, at least without adding another mini visitor.
## Test Plan
New inline tests
[pyright]:
https://pyright-play.net/?pythonVersion=3.11&strict=true&code=EYQw5gBAvBAmCWBjALgCgO4gHaygRgEoAoEaCAIgBpyiiBiCLAUwGdknYIBHAVwHt2LIgDMA5AFlwSCJhwAuCAG8IoMAG1Rs2KIC6EAL6iIxosbPmLlq5foRWiEAAcmERAAsQAJxAomnltY2wuSKogA6WKIAdABWfPBYqCAE%2BuSBVqbpWVm2iHwAtvlMWMgB2ekiolUAgq4FjgA2TAAeEMieSADWCsoV5qoaqrrGDJ5MiDz%2B8ABuLqosAIREhlXlaybrmyYMXsDw7V4AnoysyAmQ5SIhwYo3d9cheADUeKlv5O%2BpQA
## Summary
This PR updates the formatter and linter to use the `PythonVersion`
struct from the `ruff_python_ast` crate internally. While this doesn't
remove the need for the `linter::PythonVersion` enum, it does remove the
`formatter::PythonVersion` enum and limits the use in the linter to
deserializing from CLI arguments and config files and moves most of the
remaining methods to the `ast::PythonVersion` struct.
## Test Plan
Existing tests, with some inputs and outputs updated to reflect the new
(de)serialization format. I think these are test-specific and shouldn't
affect any external (de)serialization.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Fixes https://github.com/astral-sh/ruff/issues/14778
The formatter incorrectly removed the inner implicitly concatenated
string for following single-line f-string:
```py
f"{'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' 'a' if True else ""}"
# formatted
f"{ if True else ''}"
```
This happened because I changed the `RemoveSoftlinesBuffer` in
https://github.com/astral-sh/ruff/pull/14489 to remove any content
wrapped in `if_group_breaks`. After all, it emulates an *all flat*
layout. This works fine when `if_group_breaks` is only used to **add**
content if the gorup breaks. It doesn't work if the same content is
rendered differently depending on if the group fits using
`if_group_breaks` and `if_groups_fits` because the enclosing `group`
might still *break* if the entire content exceeds the line-length limit.
This PR fixes this by unwrapping any `if_group_fits` content by removing
the `if_group_fits` start and end tags.
## Test Plan
added test
## Summary
This PR fixes a bug in the f-string formatting to not consider the
escaped newlines for `is_multiline`. This is done by checking if the
f-string is triple-quoted or not similar to normal string literals.
This is not required to be gated behind preview because the logic change
for `is_multiline` was added in
https://github.com/astral-sh/ruff/pull/14454.
## Test Plan
Add a test case which formats differently on `main`:
https://play.ruff.rs/ea3c55c2-f0fe-474e-b6b8-e3365e0ede5e
## Summary
fixes: #14608
The logic that was only applied for 3.12+ target version needs to be
applied for other versions as well.
## Test Plan
I've moved the existing test cases for 3.12 only to `f_string.py` so
that it's tested against the default target version.
I think we should probably enabled testing for two target version (pre
3.12 and 3.12) but it won't highlight any issue because the parser
doesn't consider this. Maybe we should enable this once we have target
version specific syntax errors in place
(https://github.com/astral-sh/ruff/issues/6591).
## 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.
When there is a function or class definition at the end of a suite
followed by the beginning of an alternative block, we have to insert a
single empty line between them.
In the if-else-statement example below, we insert an empty line after
the `foo` in the if-block, but none after the else-block `foo`, since in
the latter case the enclosing suite already adds empty lines.
```python
if sys.version_info >= (3, 10):
def foo():
return "new"
else:
def foo():
return "old"
class Bar:
pass
```
To do so, we track whether the current suite is the last one in the
current statement with a new option on the suite kind.
Fixes#12199
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
## 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.
(Supersedes #9152, authored by @LaBatata101)
## Summary
This PR replaces the current parser generated from LALRPOP to a
hand-written recursive descent parser.
It also updates the grammar for [PEP
646](https://peps.python.org/pep-0646/) so that the parser outputs the
correct AST. For example, in `data[*x]`, the index expression is now a
tuple with a single starred expression instead of just a starred
expression.
Beyond the performance improvements, the parser is also error resilient
and can provide better error messages. The behavior as seen by any
downstream tools isn't changed. That is, the linter and formatter can
still assume that the parser will _stop_ at the first syntax error. This
will be updated in the following months.
For more details about the change here, refer to the PR corresponding to
the individual commits and the release blog post.
## Test Plan
Write _lots_ and _lots_ of tests for both valid and invalid syntax and
verify the output.
## Acknowledgements
- @MichaReiser for reviewing 100+ parser PRs and continuously providing
guidance throughout the project
- @LaBatata101 for initiating the transition to a hand-written parser in
#9152
- @addisoncrump for implementing the fuzzer which helped
[catch](https://github.com/astral-sh/ruff/pull/10903)
[a](https://github.com/astral-sh/ruff/pull/10910)
[lot](https://github.com/astral-sh/ruff/pull/10966)
[of](https://github.com/astral-sh/ruff/pull/10896)
[bugs](https://github.com/astral-sh/ruff/pull/10877)
---------
Co-authored-by: Victor Hugo Gomes <labatata101@linuxmail.org>
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
This is a follow up on https://github.com/astral-sh/ruff/pull/10492
I incorrectly assumed that `subscript.value.end()` always points past
the value. However, this isn't the case for parenthesized values where
the end "ends" before the parentheses.
## Test Plan
I added new tests for the parenthesized case.
## Summary
This PR fixes an instability where formatting a subscribt
where the `slice` is not an `ExprSlice` and it has a trailing
end-of-line comment after its opening `[` required two formatting passes
to be stable.
The fix is to associate the trailing end-of-line comment as dangling
comment on `[` to preserve its position, similar to how Ruff does it for
other parenthesized expressions.
This also matches how trailing end-of-line subscript comments are
handled when the `slice` is an `ExprSlice`.
Fixes https://github.com/astral-sh/ruff/issues/10355
## Versioning
Shipping this as part of a patch release is fine because:
* It fixes a stability issue
* It doesn't impact already formatted code because Ruff would already
have moved to the comment to the end of the line (instead of preserving
it)
## Test Plan
Added tests
## Summary
I used `codespell` and `gramma` to identify mispellings and grammar
errors throughout the codebase and fixed them. I tried not to make any
controversial changes, but feel free to revert as you see fit.
## Summary
This PR changes how we format `with` statements with a single with item
for Python 3.8 or older. This change is not compatible with Black.
This is how we format a single-item with statement today
```python
def run(data_path, model_uri):
with pyspark.sql.SparkSession.builder.config(
key="spark.python.worker.reuse", value=True
).config(key="spark.ui.enabled", value=False).master(
"local-cluster[2, 1, 1024]"
).getOrCreate():
# ignore spark log output
spark.sparkContext.setLogLevel("OFF")
print(score_model(spark, data_path, model_uri))
```
This is different than how we would format the same expression if it is
inside any other clause header (`while`, `if`, ...):
```python
def run(data_path, model_uri):
while (
pyspark.sql.SparkSession.builder.config(
key="spark.python.worker.reuse", value=True
)
.config(key="spark.ui.enabled", value=False)
.master("local-cluster[2, 1, 1024]")
.getOrCreate()
):
# ignore spark log output
spark.sparkContext.setLogLevel("OFF")
print(score_model(spark, data_path, model_uri))
```
Which seems inconsistent to me.
This PR changes the formatting of the single-item with Python 3.8 or
older to match that of other clause headers.
```python
def run(data_path, model_uri):
with (
pyspark.sql.SparkSession.builder.config(
key="spark.python.worker.reuse", value=True
)
.config(key="spark.ui.enabled", value=False)
.master("local-cluster[2, 1, 1024]")
.getOrCreate()
):
# ignore spark log output
spark.sparkContext.setLogLevel("OFF")
print(score_model(spark, data_path, model_uri))
```
According to our versioning policy, this style change is gated behind a
preview flag.
## Test Plan
See added tests.
Added
## Summary
Fixes https://github.com/astral-sh/ruff/issues/10267
The issue with the current formatting is that the formatter flips
between the `SingleParenthesizedContextManager` and
`ParenthesizeIfExpands` or `SingleWithTarget` because the layouts use
incompatible formatting ( `SingleParenthesizedContextManager`:
`maybe_parenthesize_expression(context)` vs `ParenthesizeIfExpands`:
`parenthesize_if_expands(item)`, `SingleWithTarget`:
`optional_parentheses(item)`.
The fix is to ensure that the layouts between which the formatter flips
when adding or removing parentheses are the same. I do this by
introducing a new `SingleWithoutTarget` layout that uses the same
formatting as `SingleParenthesizedContextManager` if it has no target
and prefer `SingleWithoutTarget` over using `ParenthesizeIfExpands` or
`SingleWithTarget`.
## Formatting change
The downside is that we now use `maybe_parenthesize_expression` over
`parenthesize_if_expands` for expressions where
`can_omit_optional_parentheses` returns `false`. This can lead to stable
formatting changes. I only found one formatting change in our ecosystem
check and, unfortunately, this is necessary to fix the instability (and
instability fixes are okay to have as part of minor changes according to
our versioning policy)
The benefit of the change is that `with` items with a single context
manager and without a target are now formatted identically to how the
same expression would be formatted in other clause headers.
## Test Plan
I ran the ecosystem check locally
## Summary
Fixes the handling end of line comments that belong to `**kwargs` when
the `**kwargs` come after a slash.
The issue was that we missed to include the `**kwargs` start position
when determining the start of the next node coming after the `/`.
Fixes https://github.com/astral-sh/ruff/issues/10281
## Test Plan
Added test
## Summary
_This is preview only feature and is available using the `--preview`
command-line flag._
With the implementation of [PEP 701] in Python 3.12, f-strings can now
be broken into multiple lines, can contain comments, and can re-use the
same quote character. Currently, no other Python formatter formats the
f-strings so there's some discussion which needs to happen in defining
the style used for f-string formatting. Relevant discussion:
https://github.com/astral-sh/ruff/discussions/9785
The goal for this PR is to add minimal support for f-string formatting.
This would be to format expression within the replacement field without
introducing any major style changes.
### Newlines
The heuristics for adding newline is similar to that of
[Prettier](https://prettier.io/docs/en/next/rationale.html#template-literals)
where the formatter would only split an expression in the replacement
field across multiple lines if there was already a line break within the
replacement field.
In other words, the formatter would not add any newlines unless they
were already present i.e., they were added by the user. This makes
breaking any expression inside an f-string optional and in control of
the user. For example,
```python
# We wouldn't break this
aaaaaaaaaaa = f"asaaaaaaaaaaaaaaaa { aaaaaaaaaaaa + bbbbbbbbbbbb + ccccccccccccccc } cccccccccc"
# But, we would break the following as there's already a newline
aaaaaaaaaaa = f"asaaaaaaaaaaaaaaaa {
aaaaaaaaaaaa + bbbbbbbbbbbb + ccccccccccccccc } cccccccccc"
```
If there are comments in any of the replacement field of the f-string,
then it will always be a multi-line f-string in which case the formatter
would prefer to break expressions i.e., introduce newlines. For example,
```python
x = f"{ # comment
a }"
```
### Quotes
The logic for formatting quotes remains unchanged. The existing logic is
used to determine the necessary quote char and is used accordingly.
Now, if the expression inside an f-string is itself a string like, then
we need to make sure to preserve the existing quote and not change it to
the preferred quote unless it's 3.12. For example,
```python
f"outer {'inner'} outer"
# For pre 3.12, preserve the single quote
f"outer {'inner'} outer"
# While for 3.12 and later, the quotes can be changed
f"outer {"inner"} outer"
```
But, for triple-quoted strings, we can re-use the same quote char unless
the inner string is itself a triple-quoted string.
```python
f"""outer {"inner"} outer""" # valid
f"""outer {'''inner'''} outer""" # preserve the single quote char for the inner string
```
### Debug expressions
If debug expressions are present in the replacement field of a f-string,
then the whitespace needs to be preserved as they will be rendered as it
is (for example, `f"{ x = }"`. If there are any nested f-strings, then
the whitespace in them needs to be preserved as well which means that
we'll stop formatting the f-string as soon as we encounter a debug
expression.
```python
f"outer { x = !s :.3f}"
# ^^
# We can remove these whitespaces
```
Now, the whitespace doesn't need to be preserved around conversion spec
and format specifiers, so we'll format them as usual but we won't be
formatting any nested f-string within the format specifier.
### Miscellaneous
- The
[`hug_parens_with_braces_and_square_brackets`](https://github.com/astral-sh/ruff/issues/8279)
preview style isn't implemented w.r.t. the f-string curly braces.
- The
[indentation](https://github.com/astral-sh/ruff/discussions/9785#discussioncomment-8470590)
is always relative to the f-string containing statement
## Test Plan
* Add new test cases
* Review existing snapshot changes
* Review the ecosystem changes
[PEP 701]: https://peps.python.org/pep-0701/
