rust-lang · overhacked · May 11, 2024 · Jul 31, 2024
diff --git a/src/comment.rs b/src/comment.rs
@@ -10,8 10,8 @@ use crate::rewrite::RewriteContext;
 use crate::shape::{Indent, Shape};
 use crate::string::{rewrite_string, StringFormat};
 use crate::utils::{
- count_newlines, first_line_width, last_line_width, trim_left_preserve_layout,
- trimmed_last_line_width, unicode_str_width,
  count_newlines, first_line_width, is_horizontal_space, last_line_width,
  trim_left_preserve_layout, trimmed_last_line_width, unicode_str_width,
 };
 use crate::{ErrorKind, FormattingError};
 
@@ -346,7 346,14 @@ fn identify_comment(
  let (first_group, rest) = orig.split_at(first_group_ending);
  let rewritten_first_group =
  if !config.normalize_comments() && has_bare_lines && style.is_block_comment() {
- trim_left_preserve_layout(first_group, shape.indent, config)?
  let reindented = trim_left_preserve_layout(first_group, shape.indent, config)?;
 
  // If wrap_comments is enabled, then remove any trailing blank lines
  if config.wrap_comments() {
  strip_comment_trailing_lines(reindented, style)
  } else {
  reindented
  }
  } else if !config.normalize_comments()
  && !config.wrap_comments()
  && !(
@@ -811,7 818,13 @@ impl<'a> CommentRewrite<'a> {
  } else if self.is_prev_line_multi_line && !line.is_empty() {
  self.result.push(' ')
  } else if is_last && line.is_empty() {
- // trailing blank lines are unwanted
  // Trailing blank lines are unwanted; if the last line is blank, look for additional,
  // preceding blank lines to remove, also.
  let trailing_line = self.comment_line_separator.trim_end_matches(' ');
  while self.result.ends_with(trailing_line) {
  self.result
  .truncate(self.result.len() - trailing_line.len());
  }
  if !self.closer.is_empty() {
  self.result.push_str(&self.indent_str);
  }
@@ -1047,6 1060,46 @@ fn trim_end_unless_two_whitespaces(s: &str, is_doc_comment: bool) -> &str {
  }
 }
 
 /// Removes blank lines at the end of block comments
 fn strip_comment_trailing_lines(comment: String, style: CommentStyle<'_>) -> String {
  debug_assert!(
  style.is_block_comment(),
  "strip_suffix(style.closer()) ensures this function is a no-op on non-block comments"
  );
 
  // If final line is a normal closing line, look for trailing blank lines
  if let Some(without_closer) = comment
  .strip_suffix(style.closer())
  .map(|s| s.trim_end_matches(is_horizontal_space))
  .and_then(|s| s.strip_suffix('\n'))
  {
  let mut trimmed = without_closer.trim_end();
  let closer_line = &comment[without_closer.len()..];
  let line_start = style.line_start().trim_end();
  // Start trimming trailing blank lines
  loop {
  // Remove any asterisk-prefixed or bare block comment lines
  let t = trimmed.trim_end_matches(line_start).trim_end();
  if t.len() == trimmed.len() {
  // If no trimming occurred
  break;
  } else {
  // ... otherwise, keep trying to trim
  trimmed = t;
  }
  }
 
  if without_closer.len() == trimmed.len() {
  // No blank lines were removed
  comment
  } else {
  trimmed.to_string() closer_line
  }
  } else {
  // Final line either didn't have a closer or had non-whitespace along with the closer
  comment
  }
 }
 /// Trims whitespace and aligns to indent, but otherwise does not change comments.
 fn light_rewrite_comment(
  orig: &str,

diff --git a/src/utils.rs b/src/utils.rs
@@ -675,6 675,10 @@ pub(crate) fn is_empty_line(s: &str) -> bool {
  s.is_empty() || s.chars().all(char::is_whitespace)
 }
 
 pub(crate) fn is_horizontal_space(c: char) -> bool {
  c == ' ' || c == '\t'
 }
 
 fn get_prefix_space_width(config: &Config, s: &str) -> usize {
  let mut width = 0;
  for c in s.chars() {

diff --git a/tests/source/comment_trailing_lines.rs b/tests/source/comment_trailing_lines.rs
@@ -0,0 1,28 @@
 // rustfmt-wrap_comments: true
 
 //! Module comment with multiple trailing lines
 //!
 //!
 
 /// Doc comment with multiple trailing lines
 ///
 ///
 pub mod foo {}
 
 /// Doc comment with one trailing line
 ///
 pub mod bar {}
 
 /*
  * Block comment with multiple trailing lines
  *
  *
  */
 pub mod block {}
 
 /**
 Outer Block doc comment with multiple trailing lines
 
 
  */
 pub mod outer_block_doc_comment {}
diff --git a/tests/target/comment_trailing_lines.rs b/tests/target/comment_trailing_lines.rs
@@ -0,0 1,19 @@
 // rustfmt-wrap_comments: true
 
 //! Module comment with multiple trailing lines
 
 /// Doc comment with multiple trailing lines
 pub mod foo {}
 
 /// Doc comment with one trailing line
 pub mod bar {}
 
 /*
  * Block comment with multiple trailing lines
  */
 pub mod block {}
 
 /**
 Outer Block doc comment with multiple trailing lines
  */
 pub mod outer_block_doc_comment {}