Determine when new comment lines are needed for itemized blocks

src/comment.rs

@@ -519,6 +519,7 @@ struct CommentRewrite<'a> {
     opener: String,
     closer: String,
     line_start: String,
+    style: CommentStyle<'a>,
 }
 
 impl<'a> CommentRewrite<'a> {
@@ -528,10 +529,14 @@ impl<'a> CommentRewrite<'a> {
         shape: Shape,
         config: &'a Config,
     ) -> CommentRewrite<'a> {
-        let (opener, closer, line_start) = if block_style {
-            CommentStyle::SingleBullet.to_str_tuplet()
+        let ((opener, closer, line_start), style) = if block_style {
+            (
+                CommentStyle::SingleBullet.to_str_tuplet(),
+                CommentStyle::SingleBullet,
+            )
         } else {
-            comment_style(orig, config.normalize_comments()).to_str_tuplet()
+            let style = comment_style(orig, config.normalize_comments());
+            (style.to_str_tuplet(), style)
         };
 
         let max_width = shape
@@ -564,6 +569,7 @@ impl<'a> CommentRewrite<'a> {
             opener: opener.to_owned(),
             closer: closer.to_owned(),
             line_start: line_start.to_owned(),
+            style,
         };
         cr.result.push_str(opener);
         cr
@@ -583,6 +589,15 @@ impl<'a> CommentRewrite<'a> {
         result
     }
 
+    /// Check if any characters were written to the result buffer after the start of the comment.
+    /// when calling [`CommentRewrite::new()`] the result buffer is initiazlied with the opening
+    /// characters for the comment.
+    fn buffer_contains_comment(&self) -> bool {
+        // if self.result.len() < self.opener.len() then an empty comment is in the buffer
+        // if self.result.len() > self.opener.len() then a non empty comment is in the buffer
+        self.result.len() != self.opener.len()
+    }
+
     fn finish(mut self) -> String {
         if !self.code_block_buffer.is_empty() {
             // There is a code block that is not properly enclosed by backticks.
@@ -598,7 +613,12 @@ impl<'a> CommentRewrite<'a> {
             // the last few lines are part of an itemized block
             self.fmt.shape = Shape::legacy(self.max_width, self.fmt_indent);
             let item_fmt = ib.create_string_format(&self.fmt);
-            self.result.push_str(&self.comment_line_separator);
+
+            // only push a comment_line_separator for ItemizedBlocks if the comment is not empty
+            if self.buffer_contains_comment() {
+                self.result.push_str(&self.comment_line_separator);
+            }
+
             self.result.push_str(&ib.opener);
             match rewrite_string(
                 &ib.trimmed_block_as_string(),
@@ -632,7 +652,13 @@ impl<'a> CommentRewrite<'a> {
         line: &'a str,
         has_leading_whitespace: bool,
     ) -> bool {
-        let is_last = i == count_newlines(orig);
+        let num_newlines = count_newlines(orig);
+        let is_last = i == num_newlines;
+        let needs_new_comment_line = if self.style.is_block_comment() {
+            num_newlines > 0 || self.buffer_contains_comment()
+        } else {
+            self.buffer_contains_comment()
+        };
 
         if let Some(ref mut ib) = self.item_block {
             if ib.add_line(line) {
@@ -641,7 +667,12 @@ impl<'a> CommentRewrite<'a> {
             self.is_prev_line_multi_line = false;
             self.fmt.shape = Shape::legacy(self.max_width, self.fmt_indent);
             let item_fmt = ib.create_string_format(&self.fmt);
-            self.result.push_str(&self.comment_line_separator);
+
+            // only push a comment_line_separator if we need to start a new comment line
+            if needs_new_comment_line {
+                self.result.push_str(&self.comment_line_separator);
+            }
+
             self.result.push_str(&ib.opener);
             match rewrite_string(
                 &ib.trimmed_block_as_string(),

tests/source/issue-5088/deeply_nested_long_comment_wrap_comments_true.rs

@@ -0,0 +1,33 @@
+// rustfmt-wrap_comments: true
+
+fn main() {
+    {
+        {
+            {
+                {
+                    {
+                        {
+                            {
+                                {
+                                    {
+                                        {
+                                            {
+                                                // - aaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa bbbbbbbbbb bbbbbbbbb bbbbbbbbb ccc cccccccccc ccccccc cccccccc
+
+                                                // * aaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa bbbbbbbbbb bbbbbbbbb bbbbbbbbb ccc cccccccccc ccccccc cccccccc
+
+                                                /* - aaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa bbbbbbbbbb bbbbbbbbb bbbbbbbbb ccc cccccccccc ccccccc cccccccc */
+
+                                                /* * aaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa bbbbbbbbbb bbbbbbbbb bbbbbbbbb ccc cccccccccc ccccccc cccccccc */
+                                            };
+                                        };
+                                    };
+                                };
+                            };
+                        };
+                    };
+                };
+            };
+        };
+    };
+}

tests/source/issue-5088/start_with_empty_comment_very_long_itemized_block_wrap_comments_true.rs

@@ -0,0 +1,19 @@
+// rustfmt-wrap_comments: true
+
+//
+// - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+// - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+
+//
+// * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+// * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+
+/*
+ * - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/
+/*
+ * - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/
+
+/*
+ * * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/
+/*
+ * * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/

tests/source/issue-5088/very_long_comment_wrap_comments_true.rs

@@ -0,0 +1,13 @@
+// rustfmt-wrap_comments: true
+
+// - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+// - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+
+// * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+// * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+
+/* - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/
+/* - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/
+
+/* * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/
+/* * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/

tests/target/issue-5088/deeply_nested_long_comment_wrap_comments_false.rs

@@ -0,0 +1,33 @@
+// rustfmt-wrap_comments: false
+
+fn main() {
+    {
+        {
+            {
+                {
+                    {
+                        {
+                            {
+                                {
+                                    {
+                                        {
+                                            {
+                                                // - aaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa bbbbbbbbbb bbbbbbbbb bbbbbbbbb ccc cccccccccc ccccccc cccccccc
+
+                                                // * aaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa bbbbbbbbbb bbbbbbbbb bbbbbbbbb ccc cccccccccc ccccccc cccccccc
+
+                                                /* - aaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa bbbbbbbbbb bbbbbbbbb bbbbbbbbb ccc cccccccccc ccccccc cccccccc */
+
+                                                /* * aaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa aaaaaaaaa bbbbbbbbbb bbbbbbbbb bbbbbbbbb ccc cccccccccc ccccccc cccccccc */
+                                            };
+                                        };
+                                    };
+                                };
+                            };
+                        };
+                    };
+                };
+            };
+        };
+    };
+}

tests/target/issue-5088/deeply_nested_long_comment_wrap_comments_true.rs

@@ -0,0 +1,49 @@
+// rustfmt-wrap_comments: true
+
+fn main() {
+    {
+        {
+            {
+                {
+                    {
+                        {
+                            {
+                                {
+                                    {
+                                        {
+                                            {
+                                                // - aaaa aaaaaaaaa aaaaaaaaa
+                                                //   aaaaaaaaa aaaaaaaaa
+                                                //   bbbbbbbbbb bbbbbbbbb
+                                                //   bbbbbbbbb ccc cccccccccc
+                                                //   ccccccc cccccccc
+
+                                                // * aaaa aaaaaaaaa aaaaaaaaa
+                                                //   aaaaaaaaa aaaaaaaaa
+                                                //   bbbbbbbbbb bbbbbbbbb
+                                                //   bbbbbbbbb ccc cccccccccc
+                                                //   ccccccc cccccccc
+
+                                                /* - aaaa aaaaaaaaa aaaaaaaaa
+                                                 *   aaaaaaaaa aaaaaaaaa
+                                                 *   bbbbbbbbbb bbbbbbbbb
+                                                 *   bbbbbbbbb ccc cccccccccc
+                                                 *   ccccccc cccccccc */
+
+                                                /* * aaaa aaaaaaaaa aaaaaaaaa
+                                                 *   aaaaaaaaa aaaaaaaaa
+                                                 *   bbbbbbbbbb bbbbbbbbb
+                                                 *   bbbbbbbbb ccc cccccccccc
+                                                 *   ccccccc cccccccc */
+                                            };
+                                        };
+                                    };
+                                };
+                            };
+                        };
+                    };
+                };
+            };
+        };
+    };
+}

tests/target/issue-5088/multi_line_itemized_block_wrap_comments_false.rs

@@ -0,0 +1,17 @@
+// rustfmt-wrap_comments: false
+
+// - some itemized block 1
+// - some itemized block 2
+
+// * some itemized block 3
+// * some itemized block 4
+
+/*
+ * - some itemized block 5
+ * - some itemized block 6
+ */
+
+/*
+ * * some itemized block 7
+ * * some itemized block 8
+ */

tests/target/issue-5088/multi_line_itemized_block_wrap_comments_true.rs

@@ -0,0 +1,17 @@
+// rustfmt-wrap_comments: true
+
+// - some itemized block 1
+// - some itemized block 2
+
+// * some itemized block 3
+// * some itemized block 4
+
+/*
+ * - some itemized block 5
+ * - some itemized block 6
+ */
+
+/*
+ * * some itemized block 7
+ * * some itemized block 8
+ */

tests/target/issue-5088/multi_line_text_with_itemized_block_wrap_comments_false.rs

@@ -0,0 +1,37 @@
+// rustfmt-wrap_comments: false
+
+// Some text
+// - some itemized block 1
+// - some itemized block 2
+// Some more text
+// - some itemized block 3
+// - some itemized block 4
+// Even more text
+
+// Some text
+// * some itemized block 5
+// * some itemized block 6
+// Some more text
+// * some itemized block 7
+// * some itemized block 8
+// Even more text
+
+/*
+ * Some text
+ * - some itemized block 9
+ * - some itemized block 10
+ * Some more text
+ * - some itemized block 11
+ * - some itemized block 12
+ * Even more text
+ */
+
+/*
+ * Some text
+ * * some itemized block 13
+ * * some itemized block 14
+ * Some more text
+ * * some itemized block 15
+ * * some itemized block 16
+ * Even more text
+ */

tests/target/issue-5088/multi_line_text_with_itemized_block_wrap_comments_true.rs

@@ -0,0 +1,37 @@
+// rustfmt-wrap_comments: true
+
+// Some text
+// - some itemized block 1
+// - some itemized block 2
+// Some more text
+// - some itemized block 3
+// - some itemized block 4
+// Even more text
+
+// Some text
+// * some itemized block 5
+// * some itemized block 6
+// Some more text
+// * some itemized block 7
+// * some itemized block 8
+// Even more text
+
+/*
+ * Some text
+ * - some itemized block 9
+ * - some itemized block 10
+ * Some more text
+ * - some itemized block 11
+ * - some itemized block 12
+ * Even more text
+ */
+
+/*
+ * Some text
+ * * some itemized block 13
+ * * some itemized block 14
+ * Some more text
+ * * some itemized block 15
+ * * some itemized block 16
+ * Even more text
+ */

tests/target/issue-5088/single_line_itemized_block_wrap_comments_false.rs

@@ -0,0 +1,9 @@
+// rustfmt-wrap_comments: false
+
+// - some itemized block 1
+
+// * some itemized block 2
+
+/* - some itemized block 3 */
+
+/* * some itemized block 4 */

tests/target/issue-5088/single_line_itemized_block_wrap_comments_true.rs

@@ -0,0 +1,9 @@
+// rustfmt-wrap_comments: true
+
+// - some itemized block 1
+
+// * some itemized block 2
+
+/* - some itemized block 3 */
+
+/* * some itemized block 4 */

tests/target/issue-5088/start_with_empty_comment_very_long_itemized_block_wrap_comments_false.rs

@@ -0,0 +1,19 @@
+// rustfmt-wrap_comments: false
+
+//
+// - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+// - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+
+//
+// * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+// * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+
+/*
+ * - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/
+/*
+ * - Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/
+
+/*
+ * * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/
+/*
+ * * Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.*/