try to fix comment bad wrapping (rust-lang#3099)

Author: danieledapo

src/comment.rs

@@ -579,7 +579,11 @@ fn rewrite_comment_inner(
             let item_fmt = ib.create_string_format(&fmt);
             result.push_str(&comment_line_separator);
             result.push_str(&ib.opener);
-            match rewrite_string(&item_block_buffer.replace("\n", " "), &item_fmt) {
+            match rewrite_string(
+                &item_block_buffer.replace("\n", " "),
+                &item_fmt,
+                max_chars.saturating_sub(ib.indent),
+            ) {
                 Some(s) => result.push_str(&join_block(
                     &s,
                     &format!("{}{}", &comment_line_separator, ib.line_start),
@@ -654,7 +658,7 @@ fn rewrite_comment_inner(
         }
 
         if config.wrap_comments() && line.len() > fmt.shape.width && !has_url(line) {
-            match rewrite_string(line, &fmt) {
+            match rewrite_string(line, &fmt, max_chars) {
                 Some(ref s) => {
                     is_prev_line_multi_line = s.contains('\n');
                     result.push_str(s);
@@ -665,7 +669,7 @@ fn rewrite_comment_inner(
                     result.pop();
                     result.push_str(&comment_line_separator);
                     fmt.shape = Shape::legacy(max_chars, fmt_indent);
-                    match rewrite_string(line, &fmt) {
+                    match rewrite_string(line, &fmt, max_chars) {
                         Some(ref s) => {
                             is_prev_line_multi_line = s.contains('\n');
                             result.push_str(s);
@@ -719,7 +723,11 @@ fn rewrite_comment_inner(
         let item_fmt = ib.create_string_format(&fmt);
         result.push_str(&comment_line_separator);
         result.push_str(&ib.opener);
-        match rewrite_string(&item_block_buffer.replace("\n", " "), &item_fmt) {
+        match rewrite_string(
+            &item_block_buffer.replace("\n", " "),
+            &item_fmt,
+            max_chars.saturating_sub(ib.indent),
+        ) {
             Some(s) => result.push_str(&join_block(
                 &s,
                 &format!("{}{}", &comment_line_separator, ib.line_start),

src/expr.rs

@@ -1254,6 +1254,7 @@ fn rewrite_string_lit(context: &RewriteContext, span: Span, shape: Shape) -> Opt
     rewrite_string(
         str_lit,
         &StringFormat::new(shape.visual_indent(0), context.config),
+        shape.width.saturating_sub(2),
     )
 }
 

src/string.rs

@@ -70,7 +70,11 @@ impl<'a> StringFormat<'a> {
     }
 }
 
-pub fn rewrite_string<'a>(orig: &str, fmt: &StringFormat<'a>) -> Option<String> {
+pub fn rewrite_string<'a>(
+    orig: &str,
+    fmt: &StringFormat<'a>,
+    newline_max_chars: usize,
+) -> Option<String> {
     let max_chars_with_indent = fmt.max_chars_with_indent()?;
     let max_chars_without_indent = fmt.max_chars_without_indent()?;
     let indent_with_newline = fmt.shape.indent.to_string_with_newline(fmt.config);
@@ -129,7 +133,7 @@ pub fn rewrite_string<'a>(orig: &str, fmt: &StringFormat<'a>) -> Option<String>
                 result.push_str(fmt.line_end);
                 result.push_str(&indent_with_newline);
                 result.push_str(fmt.line_start);
-                cur_max_chars = max_chars_with_indent;
+                cur_max_chars = newline_max_chars;
                 cur_start += len;
             }
             SnippetState::EndWithLineFeed(line, len) => {
@@ -358,7 +362,7 @@ mod test {
     fn issue343() {
         let config = Default::default();
         let fmt = StringFormat::new(Shape::legacy(2, Indent::empty()), &config);
-        rewrite_string("eq_", &fmt);
+        rewrite_string("eq_", &fmt, 2);
     }
 
     #[test]
@@ -463,7 +467,7 @@ mod test {
         let mut config: Config = Default::default();
         config.set().max_width(27);
         let fmt = StringFormat::new(Shape::legacy(25, Indent::empty()), &config);
-        let rewritten_string = rewrite_string(string, &fmt);
+        let rewritten_string = rewrite_string(string, &fmt, 27);
         assert_eq!(
             rewritten_string,
             Some("\"Nulla\nconsequat erat at massa. \\\n Vivamus id mi.\"".to_string())
@@ -477,11 +481,11 @@ mod test {
         let mut fmt = StringFormat::new(Shape::legacy(25, Indent::empty()), &config);
 
         fmt.trim_end = true;
-        let rewritten_string = rewrite_string(string, &fmt);
+        let rewritten_string = rewrite_string(string, &fmt, 25);
         assert_eq!(rewritten_string, Some("\"Vivamus id mi.\"".to_string()));
 
         fmt.trim_end = false; // default value of trim_end
-        let rewritten_string = rewrite_string(string, &fmt);
+        let rewritten_string = rewrite_string(string, &fmt, 25);
         assert_eq!(rewritten_string, Some("\"Vivamus id mi.  \"".to_string()));
     }
 
@@ -499,7 +503,7 @@ mod test {
             config: &config,
         };
 
-        let rewritten_string = rewrite_string(string, &fmt);
+        let rewritten_string = rewrite_string(string, &fmt, 100);
         assert_eq!(
             rewritten_string,
             Some("Vivamus id mi.\n    // Vivamus id mi.".to_string())
@@ -521,7 +525,7 @@ mod test {
         };
 
         assert_eq!(
-            rewrite_string(comment, &fmt),
+            rewrite_string(comment, &fmt, 30),
             Some(
                 "Aenean metus.\n        // Vestibulum ac lacus. Vivamus\n        // porttitor"
                     .to_string()
@@ -544,7 +548,7 @@ mod test {
         };
 
         assert_eq!(
-            rewrite_string(comment, &fmt),
+            rewrite_string(comment, &fmt, 30),
             Some(
                 "Aenean metus.\n        // Vestibulum ac lacus. Vivamus@\n        // porttitor"
                     .to_string()
@@ -567,7 +571,7 @@ mod test {
 
         let comment = "Aenean metus. Vestibulum\n\nac lacus. Vivamus porttitor";
         assert_eq!(
-            rewrite_string(comment, &fmt),
+            rewrite_string(comment, &fmt, 30),
             Some(
                 "Aenean metus. Vestibulum\n    //\n    // ac lacus. Vivamus porttitor".to_string()
             )
@@ -576,7 +580,7 @@ mod test {
         fmt.shape = Shape::legacy(15, Indent::from_width(&config, 4));
         let comment = "Aenean\n\nmetus. Vestibulum ac lacus. Vivamus porttitor";
         assert_eq!(
-            rewrite_string(comment, &fmt),
+            rewrite_string(comment, &fmt, 15),
             Some(
                 r#"Aenean
     //
@@ -603,21 +607,21 @@ mod test {
 
         let comment = "Aenean\n\nmetus. Vestibulum ac lacus.\n\n";
         assert_eq!(
-            rewrite_string(comment, &fmt),
+            rewrite_string(comment, &fmt, 20),
             Some(
                 "Aenean\n    //\n    // metus. Vestibulum ac\n    // lacus.\n    //\n".to_string()
             )
         );
 
         let comment = "Aenean\n\nmetus. Vestibulum ac lacus.\n";
         assert_eq!(
-            rewrite_string(comment, &fmt),
+            rewrite_string(comment, &fmt, 20),
             Some("Aenean\n    //\n    // metus. Vestibulum ac\n    // lacus.\n".to_string())
         );
 
         let comment = "Aenean\n        \nmetus. Vestibulum ac lacus.";
         assert_eq!(
-            rewrite_string(comment, &fmt),
+            rewrite_string(comment, &fmt, 20),
             Some("Aenean\n    //\n    // metus. Vestibulum ac\n    // lacus.".to_string())
         );
     }
@@ -637,22 +641,22 @@ mod test {
 
         let comment = "Aenean metus. Vestibulum ac lacus.";
         assert_eq!(
-            rewrite_string(comment, &fmt),
+            rewrite_string(comment, &fmt, 13),
             Some("Aenean metus.\n    // Vestibulum ac\n    // lacus.".to_string())
         );
 
         fmt.trim_end = false;
         let comment = "Vestibulum ac lacus.";
         assert_eq!(
-            rewrite_string(comment, &fmt),
+            rewrite_string(comment, &fmt, 13),
             Some("Vestibulum \n    // ac lacus.".to_string())
         );
 
         fmt.trim_end = true;
         fmt.line_end = "\\";
         let comment = "Vestibulum ac lacus.";
         assert_eq!(
-            rewrite_string(comment, &fmt),
+            rewrite_string(comment, &fmt, 13),
             Some("Vestibulum\\\n    // ac lacus.".to_string())
         );
     }

tests/source/issue-3059.rs

@@ -0,0 +1,7 @@
+// rustfmt-wrap_comments: true
+// rustfmt-max_width: 80
+
+/// Vestibulum elit nibh, rhoncus non, euismod sit amet, pretium eu, enim. Nunc commodo ultricies dui.
+/// Cras gravida rutrum massa. Donec accumsan mattis turpis. Quisque sem. Quisque elementum sapien
+/// iaculis augue. In dui sem, congue sit amet, feugiat quis, lobortis at, eros.
+fn func4() {}

tests/target/issue-3059.rs

@@ -0,0 +1,8 @@
+// rustfmt-wrap_comments: true
+// rustfmt-max_width: 80
+
+/// Vestibulum elit nibh, rhoncus non, euismod sit amet, pretium eu, enim. Nunc
+/// commodo ultricies dui. Cras gravida rutrum massa. Donec accumsan mattis
+/// turpis. Quisque sem. Quisque elementum sapien iaculis augue. In dui sem,
+/// congue sit amet, feugiat quis, lobortis at, eros.
+fn func4() {}

tests/target/itemized-blocks/wrap.rs

@@ -40,8 +40,7 @@
 /// All the parameters ***except for
 /// `from_theater`*** should be inserted as sent
 /// by the remote theater, ie. as passed to
-/// [`Theater::send`] on the remote
-/// actor:
+/// [`Theater::send`] on the remote actor:
 ///  * `from` is the sending (remote) [`ActorId`],
 ///    as reported by the remote theater by
 ///    theater-specific means
@@ -53,15 +52,13 @@
 /// All the parameters ***except for
 /// `from_theater`*** should be inserted as sent
 /// by the remote theater, ie. as passed to
-/// [`Theater::send`] on the remote
-/// actor
+/// [`Theater::send`] on the remote actor
 fn func1() {}
 
 /// All the parameters ***except for
 /// `from_theater`*** should be inserted as sent
 /// by the remote theater, ie. as passed to
-/// [`Theater::send`] on the remote
-/// actor:
+/// [`Theater::send`] on the remote actor:
 ///  * `from` is the sending (remote) [`ActorId`],
 ///    as reported by the remote theater by
 ///    theater-specific means