Preserve indent around multiline strings (#9637)

crates/ruff_python_formatter/src/expression/mod.rs

@@ -16,14 +16,11 @@ use crate::comments::{leading_comments, trailing_comments, LeadingDanglingTraili
 use crate::context::{NodeLevel, WithNodeLevel};
 use crate::expression::expr_generator_exp::is_generator_parenthesized;
 use crate::expression::parentheses::{
-    is_expression_parenthesized, optional_parentheses, parenthesized, HuggingStyle,
-    NeedsParentheses, OptionalParentheses, Parentheses, Parenthesize,
+    is_expression_parenthesized, optional_parentheses, parenthesized, NeedsParentheses,
+    OptionalParentheses, Parentheses, Parenthesize,
 };
 use crate::prelude::*;
-use crate::preview::{
-    is_hug_parens_with_braces_and_square_brackets_enabled, is_multiline_string_handling_enabled,
-};
-use crate::string::AnyString;
+use crate::preview::is_hug_parens_with_braces_and_square_brackets_enabled;
 
 mod binary_like;
 pub(crate) mod expr_attribute;
@@ -446,7 +443,7 @@ impl Format<PyFormatContext<'_>> for MaybeParenthesizeExpression<'_> {
             OptionalParentheses::Never => match parenthesize {
                 Parenthesize::IfBreaksOrIfRequired => {
                     parenthesize_if_expands(&expression.format().with_options(Parentheses::Never))
-                        .with_indent(is_expression_huggable(expression, f.context()).is_none())
+                        .with_indent(!is_expression_huggable(expression, f.context()))
                         .fmt(f)
                 }
 
@@ -1112,26 +1109,18 @@ pub(crate) fn has_own_parentheses(
 ///     ]
 /// )
 /// ```
-pub(crate) fn is_expression_huggable(
-    expr: &Expr,
-    context: &PyFormatContext,
-) -> Option<HuggingStyle> {
+pub(crate) fn is_expression_huggable(expr: &Expr, context: &PyFormatContext) -> bool {
     match expr {
         Expr::Tuple(_)
         | Expr::List(_)
         | Expr::Set(_)
         | Expr::Dict(_)
         | Expr::ListComp(_)
         | Expr::SetComp(_)
-        | Expr::DictComp(_) => is_hug_parens_with_braces_and_square_brackets_enabled(context)
-            .then_some(HuggingStyle::Always),
+        | Expr::DictComp(_) => is_hug_parens_with_braces_and_square_brackets_enabled(context),
 
         Expr::Starred(ast::ExprStarred { value, .. }) => is_expression_huggable(value, context),
 
-        Expr::StringLiteral(string) => is_huggable_string(AnyString::String(string), context),
-        Expr::BytesLiteral(bytes) => is_huggable_string(AnyString::Bytes(bytes), context),
-        Expr::FString(fstring) => is_huggable_string(AnyString::FString(fstring), context),
-
         Expr::BoolOp(_)
         | Expr::NamedExpr(_)
         | Expr::BinOp(_)
@@ -1152,20 +1141,10 @@ pub(crate) fn is_expression_huggable(
         | Expr::NumberLiteral(_)
         | Expr::BooleanLiteral(_)
         | Expr::NoneLiteral(_)
-        | Expr::EllipsisLiteral(_) => None,
-    }
-}
-
-/// Returns `true` if `string` is a multiline string that is not implicitly concatenated.
-fn is_huggable_string(string: AnyString, context: &PyFormatContext) -> Option<HuggingStyle> {
-    if !is_multiline_string_handling_enabled(context) {
-        return None;
-    }
-
-    if !string.is_implicit_concatenated() && string.is_multiline(context.source()) {
-        Some(HuggingStyle::IfFirstLineFits)
-    } else {
-        None
+        | Expr::StringLiteral(_)
+        | Expr::BytesLiteral(_)
+        | Expr::FString(_)
+        | Expr::EllipsisLiteral(_) => false,
     }
 }
 

crates/ruff_python_formatter/src/expression/parentheses.rs

@@ -126,7 +126,7 @@ where
     FormatParenthesized {
         left,
         comments: &[],
-        hug: None,
+        hug: false,
         content: Argument::new(content),
         right,
     }
@@ -135,7 +135,7 @@ where
 pub(crate) struct FormatParenthesized<'content, 'ast> {
     left: &'static str,
     comments: &'content [SourceComment],
-    hug: Option<HuggingStyle>,
+    hug: bool,
     content: Argument<'content, PyFormatContext<'ast>>,
     right: &'static str,
 }
@@ -158,10 +158,7 @@ impl<'content, 'ast> FormatParenthesized<'content, 'ast> {
     }
 
     /// Whether to indent the content within the parentheses.
-    pub(crate) fn with_hugging(
-        self,
-        hug: Option<HuggingStyle>,
-    ) -> FormatParenthesized<'content, 'ast> {
+    pub(crate) fn with_hugging(self, hug: bool) -> FormatParenthesized<'content, 'ast> {
         FormatParenthesized { hug, ..self }
     }
 }
@@ -173,30 +170,10 @@ impl<'ast> Format<PyFormatContext<'ast>> for FormatParenthesized<'_, 'ast> {
         let indented = format_with(|f| {
             let content = Arguments::from(&self.content);
             if self.comments.is_empty() {
-                match self.hug {
-                    None => group(&soft_block_indent(&content)).fmt(f),
-                    Some(HuggingStyle::Always) => content.fmt(f),
-                    Some(HuggingStyle::IfFirstLineFits) => {
-                        // It's not immediately obvious how the below IR works to only indent the content if the first line exceeds the configured line width.
-                        // The trick is the first group that doesn't wrap `self.content`.
-                        // * The group doesn't wrap `self.content` because we need to assume that `self.content`
-                        //   contains a hard line break and hard-line-breaks always expand the enclosing group.
-                        // * The printer decides that a group fits if its content (in this case a `soft_line_break` that has a width of 0 and is guaranteed to fit)
-                        //   and the content coming after the group in expanded mode (`self.content`) fits on the line.
-                        //   The content coming after fits if the content up to the first soft or hard line break (or the end of the document) fits.
-                        //
-                        // This happens to be right what we want. The first group should add an indent and a soft line break if the content of `self.content`
-                        // up to the first line break exceeds the configured line length, but not otherwise.
-                        let indented = f.group_id("indented_content");
-                        write!(
-                            f,
-                            [
-                                group(&indent(&soft_line_break())).with_group_id(Some(indented)),
-                                indent_if_group_breaks(&content, indented),
-                                if_group_breaks(&soft_line_break()).with_group_id(Some(indented))
-                            ]
-                        )
-                    }
+                if self.hug {
+                    content.fmt(f)
+                } else {
+                    group(&soft_block_indent(&content)).fmt(f)
                 }
             } else {
                 group(&format_args![
@@ -228,20 +205,6 @@ impl<'ast> Format<PyFormatContext<'ast>> for FormatParenthesized<'_, 'ast> {
     }
 }
 
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
-pub(crate) enum HuggingStyle {
-    /// Always hug the content (never indent).
-    Always,
-
-    /// Hug the content if the content up to the first line break fits into the configured line length. Otherwise indent the content.
-    ///
-    /// This is different from [`HuggingStyle::Always`] in that it doesn't indent if the content contains a hard line break, and the content up to that hard line break fits into the configured line length.
-    ///
-    /// This style is used for formatting multiline strings that, by definition, always break. The idea is to
-    /// only hug a multiline string if its content up to the first line breaks exceeds the configured line length.
-    IfFirstLineFits,
-}
-
 /// Wraps an expression in parentheses only if it still does not fit after expanding all expressions that start or end with
 /// a parentheses (`()`, `[]`, `{}`).
 pub(crate) fn optional_parentheses<'content, 'ast, Content>(

crates/ruff_python_formatter/src/other/arguments.rs

@@ -1,16 +1,16 @@
 use ruff_formatter::{write, FormatContext};
 use ruff_python_ast::{ArgOrKeyword, Arguments, Expr};
-use ruff_python_trivia::{SimpleTokenKind, SimpleTokenizer};
-use ruff_text_size::{Ranged, TextRange, TextSize};
+use ruff_python_trivia::{PythonWhitespace, SimpleTokenKind, SimpleTokenizer};
+use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 
 use crate::comments::SourceComment;
 use crate::expression::expr_generator_exp::GeneratorExpParentheses;
 use crate::expression::is_expression_huggable;
-use crate::expression::parentheses::{
-    empty_parenthesized, parenthesized, HuggingStyle, Parentheses,
-};
+use crate::expression::parentheses::{empty_parenthesized, parenthesized, Parentheses};
 use crate::other::commas;
 use crate::prelude::*;
+use crate::preview::is_multiline_string_handling_enabled;
+use crate::string::AnyString;
 
 #[derive(Default)]
 pub struct FormatArguments;
@@ -178,33 +178,75 @@ fn is_single_argument_parenthesized(argument: &Expr, call_end: TextSize, source:
 ///
 /// Hugging should only be applied to single-argument collections, like lists, or starred versions
 /// of those collections.
-fn is_arguments_huggable(item: &Arguments, context: &PyFormatContext) -> Option<HuggingStyle> {
+fn is_arguments_huggable(arguments: &Arguments, context: &PyFormatContext) -> bool {
     // Find the lone argument or `**kwargs` keyword.
-    let arg = match (item.args.as_slice(), item.keywords.as_slice()) {
+    let arg = match (arguments.args.as_slice(), arguments.keywords.as_slice()) {
         ([arg], []) => arg,
         ([], [keyword]) if keyword.arg.is_none() && !context.comments().has(keyword) => {
             &keyword.value
         }
-        _ => return None,
+        _ => return false,
     };
 
     // If the expression itself isn't huggable, then we can't hug it.
-    let hugging_style = is_expression_huggable(arg, context)?;
+    if !(is_expression_huggable(arg, context)
+        || AnyString::from_expression(arg)
+            .is_some_and(|string| is_huggable_string_argument(string, arguments, context)))
+    {
+        return false;
+    }
 
     // If the expression has leading or trailing comments, then we can't hug it.
     let comments = context.comments().leading_dangling_trailing(arg);
     if comments.has_leading() || comments.has_trailing() {
-        return None;
+        return false;
     }
 
     let options = context.options();
 
     // If the expression has a trailing comma, then we can't hug it.
     if options.magic_trailing_comma().is_respect()
-        && commas::has_magic_trailing_comma(TextRange::new(arg.end(), item.end()), options, context)
+        && commas::has_magic_trailing_comma(
+            TextRange::new(arg.end(), arguments.end()),
+            options,
+            context,
+        )
     {
-        return None;
+        return false;
+    }
+
+    true
+}
+
+/// Returns `true` if `string` is a multiline string that is not implicitly concatenated and there's no
+/// newline between the opening parentheses of arguments and the quotes of the string:
+///
+/// ```python
+/// # Hug this string
+/// call("""test
+/// multiline""")
+///
+/// # Don't hug because there's a newline between the opening parentheses and the quotes:
+/// call(
+///     """"
+///     test
+///     """"
+/// )
+/// ```
+fn is_huggable_string_argument(
+    string: AnyString,
+    arguments: &Arguments,
+    context: &PyFormatContext,
+) -> bool {
+    if !is_multiline_string_handling_enabled(context) {
+        return false;
+    }
+
+    if string.is_implicit_concatenated() || !string.is_multiline(context.source()) {
+        return false;
     }
 
-    Some(hugging_style)
+    let between_parens_range = TextRange::new(arguments.start() + '('.text_len(), string.start());
+    let between_parens = &context.source()[between_parens_range];
+    !between_parens.trim_whitespace_end().ends_with(['\n', '\r'])
 }

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__preview_multiline_strings.py.snap

@@ -301,7 +301,19 @@ this_will_also_become_one_line = (  # comment
  # Another use case
  data = yaml.load("""\
  a: 1
-@@ -85,11 +114,13 @@
+@@ -77,19 +106,23 @@
+ b: 2
+ """,
+ )
+-data = yaml.load("""\
++data = yaml.load(
++    """\
+     a: 1
+     b: 2
+-""")
++"""
++)
+ 
  MULTILINE = """
  foo
  """.replace("\n", "")
@@ -316,7 +328,7 @@ this_will_also_become_one_line = (  # comment
  parser.usage += """
  Custom extra help summary.
  
-@@ -156,16 +187,24 @@
+@@ -156,16 +189,24 @@
               10 LOAD_CONST               0 (None)
               12 RETURN_VALUE
  """ % (_C.__init__.__code__.co_firstlineno + 1,)
@@ -347,7 +359,7 @@ this_will_also_become_one_line = (  # comment
  [
      """cow
  moos""",
-@@ -198,7 +237,7 @@
+@@ -198,7 +239,7 @@
  `--global-option` is reserved to flags like `--verbose` or `--quiet`.
  """
  
@@ -356,7 +368,7 @@ this_will_also_become_one_line = (  # comment
  
  this_will_stay_on_three_lines = (
      "a"  # comment
-@@ -206,4 +245,6 @@
+@@ -206,4 +247,6 @@
      "c"
  )
  
@@ -477,10 +489,12 @@ a: 1
 b: 2
 """,
 )
-data = yaml.load("""\
+data = yaml.load(
+    """\
     a: 1
     b: 2
-""")
+"""
+)
 
 MULTILINE = """
 foo