mirror of
https://github.com/astral-sh/ruff
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4e1cf5747a
This PR implements a modification (in preview) to fluent formatting for
method chains: We break _at_ the first call instead of _after_.
For example, we have the following diff between `main` and this PR (with
`line-length=8` so I don't have to stretch out the text):
```diff
x = (
- df.merge()
+ df
+ .merge()
.groupby()
.agg()
.filter()
)
```
## Explanation of current implementation
Recall that we traverse the AST to apply formatting. A method chain,
while read left-to-right, is stored in the AST "in reverse". So if we
start with something like
```python
a.b.c.d().e.f()
```
then the first syntax node we meet is essentially `.f()`. So we have to
peek ahead. And we actually _already_ do this in our current fluent
formatting logic: we peek ahead to count how many calls we have in the
chain to see whether we should be using fluent formatting or now.
In this implementation, we actually _record_ this number inside the enum
for `CallChainLayout`. That is, we make the variant `Fluent` hold an
`AttributeState`. This state can either be:
- The number of call-like attributes preceding the current attribute
- The state `FirstCallOrSubscript` which means we are at the first
call-like attribute in the chain (reading from left to right)
- The state `BeforeFirstCallOrSubscript` which means we are in the
"first group" of attributes, preceding that first call.
In our example, here's what it looks like at each attribute:
```
a.b.c.d().e.f @ Fluent(CallsOrSubscriptsPreceding(1))
a.b.c.d().e @ Fluent(CallsOrSubscriptsPreceding(1))
a.b.c.d @ Fluent(FirstCallOrSubscript)
a.b.c @ Fluent(BeforeFirstCallOrSubscript)
a.b @ Fluent(BeforeFirstCallOrSubscript)
```
Now, as we descend down from the parent expression, we pass along this
little piece of state and modify it as we go to track where we are. This
state doesn't do anything except when we are in `FirstCallOrSubscript`,
in which case we add a soft line break.
Closes #8598
---------
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
69 lines
2.7 KiB
Rust
69 lines
2.7 KiB
Rust
//! Helpers to test if a specific preview style is enabled or not.
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//!
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//! The motivation for these functions isn't to avoid code duplication but to ease promoting preview styles
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//! to stable. The challenge with directly using [`is_preview`](PyFormatContext::is_preview) is that it is unclear
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//! for which specific feature this preview check is for. Having named functions simplifies the promotion:
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//! Simply delete the function and let Rust tell you which checks you have to remove.
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use crate::PyFormatContext;
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/// Returns `true` if the [`hug_parens_with_braces_and_square_brackets`](https://github.com/astral-sh/ruff/issues/8279) preview style is enabled.
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pub(crate) const fn is_hug_parens_with_braces_and_square_brackets_enabled(
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context: &PyFormatContext,
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) -> bool {
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context.is_preview()
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}
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/// Returns `true` if the [`no_chaperone_for_escaped_quote_in_triple_quoted_docstring`](https://github.com/astral-sh/ruff/pull/17216) preview style is enabled.
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pub(crate) const fn is_no_chaperone_for_escaped_quote_in_triple_quoted_docstring_enabled(
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context: &PyFormatContext,
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) -> bool {
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context.is_preview()
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}
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/// Returns `true` if the [`blank_line_before_decorated_class_in_stub`](https://github.com/astral-sh/ruff/issues/18865) preview style is enabled.
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pub(crate) const fn is_blank_line_before_decorated_class_in_stub_enabled(
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context: &PyFormatContext,
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) -> bool {
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context.is_preview()
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}
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/// Returns `true` if the
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/// [`remove_parens_around_except_types`](https://github.com/astral-sh/ruff/pull/20768) preview
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/// style is enabled.
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pub(crate) const fn is_remove_parens_around_except_types_enabled(
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context: &PyFormatContext,
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) -> bool {
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context.is_preview()
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}
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/// Returns `true` if the
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/// [`allow_newline_after_block_open`](https://github.com/astral-sh/ruff/pull/21110) preview style
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/// is enabled.
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pub(crate) const fn is_allow_newline_after_block_open_enabled(context: &PyFormatContext) -> bool {
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context.is_preview()
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}
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/// Returns `true` if the
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/// [`avoid_parens_for_long_as_captures`](https://github.com/astral-sh/ruff/pull/21176) preview
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/// style is enabled.
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pub(crate) const fn is_avoid_parens_for_long_as_captures_enabled(
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context: &PyFormatContext,
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) -> bool {
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context.is_preview()
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}
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/// Returns `true` if the
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/// [`parenthesize_lambda_bodies`](https://github.com/astral-sh/ruff/pull/21385) preview style is
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/// enabled.
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pub(crate) const fn is_parenthesize_lambda_bodies_enabled(context: &PyFormatContext) -> bool {
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context.is_preview()
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}
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/// Returns `true` if the
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/// [`fluent_layout_split_first_call`](https://github.com/astral-sh/ruff/pull/21369) preview
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/// style is enabled.
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pub(crate) const fn is_fluent_layout_split_first_call_enabled(context: &PyFormatContext) -> bool {
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context.is_preview()
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}
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