Add FString support to binary like formatting

## Summary

This is the last part of the string - binary like formatting. It adds support for handling fstrings the same as "regular" strings.


## Test Plan

I added a test for both binary and comparison. 

Small improvements across several projects

**This PR**
| project      | similarity index  | total files       | changed files     |
|--------------|------------------:|------------------:|------------------:|
| cpython      |           0.76083 |              1789 |              1632 |
| django       |           0.99966 |              2760 |                58 |
| **transformers** |           0.99929 |              2587 |               454 |
| twine        |           1.00000 |                33 |                 0 |
| typeshed     |           0.99978 |              3496 |              2173 |
| **warehouse**    |           0.99825 |               648 |                22 |
| **zulip**        |           0.99950 |              1437 |                27 |


**Base**

| project      | similarity index  | total files       | changed files     |
|--------------|------------------:|------------------:|------------------:|
| cpython      |           0.76083 |              1789 |              1632 |
| django       |           0.99966 |              2760 |                58 |
| transformers |           0.99928 |              2587 |               454 |
| twine        |           1.00000 |                33 |                 0 |
| typeshed     |           0.99978 |              3496 |              2173 |
| warehouse    |           0.99824 |               648 |                22 |
| zulip        |           0.99948 |              1437 |                28 |


<!-- How was it tested? -->

crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/binary_implicit_string.py

@@ -84,6 +84,15 @@ self._assert_skipping(
     + x
 )
 
+(
+    b + c + d +
+    "aaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    f"bbbbbb{z}bbbbbbbbbbbbbbbbbbbbbbb"
+    "cccccccccccccccccccccccccc"
+    % aaaaaaaaaaaa
+    + x
+)
+
 (
     b < c > d <
     "aaaaaaaaaaaaaaaaaaaaaaaaaaaaa"

crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/compare.py

@@ -131,6 +131,15 @@ assert (
     in caplog.messages
 )
 
+(
+    b < c > d <
+    f"aaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    "bbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
+    "cccccccccccccccccccccccccc"
+    % aaaaaaaaaaaa
+    > x
+)
+
 c = (a >
      # test leading binary comment
      "a" "b" * b

crates/ruff_python_formatter/src/expression/binary_like.rs

@@ -5,18 +5,16 @@ use smallvec::SmallVec;
 
 use ruff_formatter::write;
 use ruff_python_ast::{
-    BytesConstant, Constant, Expr, ExprAttribute, ExprBinOp, ExprCompare, ExprConstant,
+    Constant, Expr, ExprAttribute, ExprBinOp, ExprCompare, ExprConstant, ExprUnaryOp, UnaryOp,
-    ExprUnaryOp, StringConstant, UnaryOp,
 };
 
 use crate::comments::{leading_comments, trailing_comments, Comments, SourceComment};
-use crate::expression::expr_constant::ExprConstantLayout;
 use crate::expression::parentheses::{
     in_parentheses_only_group, in_parentheses_only_soft_line_break,
     in_parentheses_only_soft_line_break_or_space, is_expression_parenthesized,
     write_in_parentheses_only_group_end_tag, write_in_parentheses_only_group_start_tag,
 };
-use crate::expression::string::StringLayout;
+use crate::expression::string::{AnyString, FormatString, StringLayout};
 use crate::expression::OperatorPrecedence;
 use crate::prelude::*;
 
@@ -197,29 +195,12 @@ impl Format<PyFormatContext<'_>> for BinaryLike<'_> {
         let mut string_operands = flat_binary
             .operands()
             .filter_map(|(index, operand)| {
-                if let Expr::Constant(
+                AnyString::from_expression(operand.expression())
-                    constant @ ExprConstant {
+                    .filter(|string| {
-                        value:
+                        string.is_implicit_concatenated()
-                            Constant::Str(StringConstant {
+                            && !is_expression_parenthesized(string.into(), source)
-                                implicit_concatenated: true,
+                    })
-                                ..
+                    .map(|string| (index, string, operand))
-                            })
-                            | Constant::Bytes(BytesConstant {
-                                implicit_concatenated: true,
-                                ..
-                            }),
-                        ..
-                    },
-                ) = operand.expression()
-                {
-                    if is_expression_parenthesized(constant.into(), source) {
-                        None
-                    } else {
-                        Some((index, constant, operand))
-                    }
-                } else {
-                    None
-                }
             })
             .peekable();
 
@@ -296,11 +277,11 @@ impl Format<PyFormatContext<'_>> for BinaryLike<'_> {
                             f,
                             [
                                 operand.leading_binary_comments().map(leading_comments),
-                                string_constant
+                                leading_comments(comments.leading(&string_constant)),
-                                    .format()
+                                FormatString::new(&string_constant).with_layout(
-                                    .with_options(ExprConstantLayout::String(
+                                    StringLayout::ImplicitConcatenatedStringInBinaryLike,
-                                        StringLayout::ImplicitConcatenatedStringInBinaryLike,
+                                ),
-                                    )),
+                                trailing_comments(comments.trailing(&string_constant)),
                                 operand.trailing_binary_comments().map(trailing_comments),
                                 line_suffix_boundary(),
                             ]
@@ -311,12 +292,16 @@ impl Format<PyFormatContext<'_>> for BinaryLike<'_> {
                         // "a" "b" + c
                         // ^^^^^^^-- format the first operand of a binary expression
                         // ```
-                        string_constant
+                        write!(
-                            .format()
+                            f,
-                            .with_options(ExprConstantLayout::String(
+                            [
-                                StringLayout::ImplicitConcatenatedStringInBinaryLike,
+                                leading_comments(comments.leading(&string_constant)),
-                            ))
+                                FormatString::new(&string_constant).with_layout(
-                            .fmt(f)?;
+                                    StringLayout::ImplicitConcatenatedStringInBinaryLike
+                                ),
+                                trailing_comments(comments.trailing(&string_constant)),
+                            ]
+                        )?;
                     }
 
                     // Write the right operator and start the group for the right side (if any)

crates/ruff_python_formatter/src/expression/string.rs

@@ -4,7 +4,7 @@ use bitflags::bitflags;
 
 use ruff_formatter::{format_args, write, FormatError, FormatOptions, TabWidth};
 use ruff_python_ast::node::AnyNodeRef;
-use ruff_python_ast::{self as ast, ExprConstant, ExprFString};
+use ruff_python_ast::{self as ast, Constant, ExprConstant, ExprFString, ExpressionRef};
 use ruff_python_parser::lexer::{lex_starts_at, LexicalError, LexicalErrorType};
 use ruff_python_parser::{Mode, Tok};
 use ruff_source_file::Locator;
@@ -24,12 +24,26 @@ enum Quoting {
     Preserve,
 }
 
+#[derive(Clone, Debug)]
 pub(super) enum AnyString<'a> {
     Constant(&'a ExprConstant),
     FString(&'a ExprFString),
 }
 
 impl<'a> AnyString<'a> {
+    pub(crate) fn from_expression(expression: &'a Expr) -> Option<AnyString<'a>> {
+        match expression {
+            Expr::Constant(
+                constant @ ExprConstant {
+                    value: Constant::Str(_) | Constant::Bytes(_),
+                    ..
+                },
+            ) => Some(AnyString::Constant(constant)),
+            Expr::FString(fstring) => Some(AnyString::FString(fstring)),
+            _ => None,
+        }
+    }
+
     fn quoting(&self, locator: &Locator) -> Quoting {
         match self {
             Self::Constant(_) => Quoting::CanChange,
@@ -50,7 +64,7 @@ impl<'a> AnyString<'a> {
     }
 
     /// Returns `true` if the string is implicitly concatenated.
-    fn implicit_concatenated(&self) -> bool {
+    pub(super) fn is_implicit_concatenated(&self) -> bool {
         match self {
             Self::Constant(ExprConstant { value, .. }) => value.is_implicit_concatenated(),
             Self::FString(ExprFString {
@@ -79,6 +93,15 @@ impl<'a> From<&AnyString<'a>> for AnyNodeRef<'a> {
     }
 }
 
+impl<'a> From<&AnyString<'a>> for ExpressionRef<'a> {
+    fn from(value: &AnyString<'a>) -> Self {
+        match value {
+            AnyString::Constant(expr) => ExpressionRef::Constant(expr),
+            AnyString::FString(expr) => ExpressionRef::FString(expr),
+        }
+    }
+}
+
 pub(super) struct FormatString<'a> {
     string: &'a AnyString<'a>,
     layout: StringLayout,
@@ -97,7 +120,7 @@ pub enum StringLayout {
 }
 
 impl<'a> FormatString<'a> {
-    pub(super) fn new(string: &'a AnyString) -> Self {
+    pub(super) fn new(string: &'a AnyString<'a>) -> Self {
         if let AnyString::Constant(constant) = string {
             debug_assert!(constant.value.is_str() || constant.value.is_bytes());
         }
@@ -117,7 +140,7 @@ impl<'a> Format<PyFormatContext<'_>> for FormatString<'a> {
     fn fmt(&self, f: &mut PyFormatter) -> FormatResult<()> {
         match self.layout {
             StringLayout::Default => {
-                if self.string.implicit_concatenated() {
+                if self.string.is_implicit_concatenated() {
                     in_parentheses_only_group(&FormatStringContinuation::new(self.string)).fmt(f)
                 } else {
                     FormatStringPart::new(
@@ -972,9 +995,10 @@ fn format_docstring_line(
 
 #[cfg(test)]
 mod tests {
-    use crate::expression::string::count_indentation_like_black;
     use ruff_formatter::TabWidth;
 
+    use crate::expression::string::count_indentation_like_black;
+
     #[test]
     fn test_indentation_like_black() {
         let tab_width = TabWidth::try_from(8).unwrap();

crates/ruff_python_formatter/tests/snapshots/format@expression__binary_implicit_string.py.snap

@@ -90,6 +90,15 @@ self._assert_skipping(
     + x
 )
 
+(
+    b + c + d +
+    "aaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    f"bbbbbb{z}bbbbbbbbbbbbbbbbbbbbbbb"
+    "cccccccccccccccccccccccccc"
+    % aaaaaaaaaaaa
+    + x
+)
+
 (
     b < c > d <
     "aaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
@@ -266,6 +275,12 @@ self._assert_skipping(
     "cccccccccccccccccccccccccc" % aaaaaaaaaaaa + x
 )
 
+(
+    b + c + d + "aaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    f"bbbbbb{z}bbbbbbbbbbbbbbbbbbbbbbb"
+    "cccccccccccccccccccccccccc" % aaaaaaaaaaaa + x
+)
+
 (
     b < c > d < "aaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
     "bbbbbbbbbbbbbbbbbbbbbbbbbbbbb"

crates/ruff_python_formatter/tests/snapshots/format@expression__compare.py.snap

@@ -137,6 +137,15 @@ assert (
     in caplog.messages
 )
 
+(
+    b < c > d <
+    f"aaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    "bbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
+    "cccccccccccccccccccccccccc"
+    % aaaaaaaaaaaa
+    > x
+)
+
 c = (a >
      # test leading binary comment
      "a" "b" * b
@@ -356,6 +365,12 @@ assert (
     "be silently ignored by the index" in caplog.messages
 )
 
+(
+    b < c > d < f"aaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    "bbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
+    "cccccccccccccccccccccccccc" % aaaaaaaaaaaa > x
+)
+
 c = (
     a >
     # test leading binary comment