From 0489bbc54ced7edae1bff606e3cae024a53bb77c Mon Sep 17 00:00:00 2001
From: Chris Pryer <14341145+cnpryer@users.noreply.github.com>
Date: Fri, 1 Sep 2023 08:52:59 -0400
Subject: [PATCH] Match Black's formatting of trailing comments containing NBSP
 (#7030)

---
 .../src/comments/format.rs                    | 19 ++++++++++---------
 .../format@trailing_comments.py.snap          |  4 ++--
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/crates/ruff_python_formatter/src/comments/format.rs b/crates/ruff_python_formatter/src/comments/format.rs
index e682924284d56..6a6cb33768e16 100644
--- a/crates/ruff_python_formatter/src/comments/format.rs
+++ b/crates/ruff_python_formatter/src/comments/format.rs
@@ -474,18 +474,19 @@ fn normalize_comment<'a>(
     if content.starts_with('\u{A0}') {
         let trimmed = content.trim_start_matches('\u{A0}');
 
-        // Black adds a space before the non-breaking space if part of a type pragma.
         if trimmed.trim_start().starts_with("type:") {
-            return Ok(Cow::Owned(std::format!("# \u{A0}{trimmed}")));
-        }
-
-        // Black replaces the non-breaking space with a space if followed by a space.
-        if trimmed.starts_with(' ') {
-            return Ok(Cow::Owned(std::format!("# {trimmed}")));
+            // Black adds a space before the non-breaking space if part of a type pragma.
+            Ok(Cow::Owned(std::format!("# {content}")))
+        } else if trimmed.starts_with(' ') {
+            // Black replaces the non-breaking space with a space if followed by a space.
+            Ok(Cow::Owned(std::format!("# {trimmed}")))
+        } else {
+            // Otherwise we replace the first non-breaking space with a regular space.
+            Ok(Cow::Owned(std::format!("# {}", &content["\u{A0}".len()..])))
         }
+    } else {
+        Ok(Cow::Owned(std::format!("# {}", content.trim_start())))
     }
-
-    Ok(Cow::Owned(std::format!("# {}", content.trim_start())))
 }
 
 /// A helper for stripping '#' from comments.
diff --git a/crates/ruff_python_formatter/tests/snapshots/format@trailing_comments.py.snap b/crates/ruff_python_formatter/tests/snapshots/format@trailing_comments.py.snap
index 982bb00711926..7e6a4bdc161e4 100644
--- a/crates/ruff_python_formatter/tests/snapshots/format@trailing_comments.py.snap
+++ b/crates/ruff_python_formatter/tests/snapshots/format@trailing_comments.py.snap
@@ -65,11 +65,11 @@ i = ""  #          type: Add space before leading NBSP followed by spaces
 i = ""  # type: A space is added
 i = ""  #   type: Add space before leading NBSP followed by a space
 i = ""  #  type: Add space before leading NBSP
-i = ""  #  type: Add space before two leading NBSP
+i = ""  #   type: Add space before two leading NBSP
 
 
 # A noqa as `#\u{A0}\u{A0}noqa` becomes `# \u{A0}noqa`
-i = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"  # noqa
+i = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"  #  noqa
 ```