Keep trailing newline in module level docstring

crates/ruff_python_formatter/src/other/string_literal.rs

@@ -1,6 +1,7 @@
 use ruff_python_ast::StringLiteral;
 use ruff_text_size::Ranged;
 
+use crate::context::NodeLevel;
 use crate::prelude::*;
 use crate::preview::is_hex_codes_in_unicode_sequences_enabled;
 use crate::string::{docstring, Quoting, StringPart};
@@ -66,7 +67,8 @@ impl Format<PyFormatContext<'_>> for FormatStringLiteral<'_> {
         );
 
         if self.layout.is_docstring() {
-            docstring::format(&normalized, f)
+            let is_top_level = matches!(f.context().node_level(), NodeLevel::TopLevel(_));
+            docstring::format(&normalized, f, is_top_level)
         } else {
             normalized.fmt(f)
         }

crates/ruff_python_formatter/src/string/docstring.rs

@@ -5,6 +5,7 @@
 use std::{borrow::Cow, collections::VecDeque};
 
 use ruff_python_parser::ParseError;
+use ruff_source_file::NewlineWithTrailingNewline;
 use {once_cell::sync::Lazy, regex::Regex};
 use {
     ruff_formatter::{write, FormatOptions, IndentStyle, LineWidth, Printed},
@@ -102,7 +103,11 @@ use super::{NormalizedString, QuoteChar};
 ///         line c
 ///    """
 /// ```
-pub(crate) fn format(normalized: &NormalizedString, f: &mut PyFormatter) -> FormatResult<()> {
+pub(crate) fn format(
+    normalized: &NormalizedString,
+    f: &mut PyFormatter,
+    is_module: bool,
+) -> FormatResult<()> {
     let docstring = &normalized.text;
 
     // Black doesn't change the indentation of docstrings that contain an escaped newline
@@ -201,6 +206,16 @@ pub(crate) fn format(normalized: &NormalizedString, f: &mut PyFormatter) -> Form
     let trim_end = docstring
         .as_ref()
         .trim_end_matches(|c: char| c.is_whitespace() && c != '\n');
+
+    // When there is a trailing newline, we want to keep it for module docstrings
+    if ({
+        let ref this = trim_end;
+        this.ends_with(&['\r', '\n'][..])
+    }) && is_module
+    {
+        hard_line_break().fmt(f)?;
+    }
+
     if needs_chaperone_space(normalized, trim_end) {
         space().fmt(f)?;
     }