From a91eb73064c9bef76c3a961ab662bb5f75a1543d Mon Sep 17 00:00:00 2001
From: Eddie Darling <darling@berkeley.edu>
Date: Sun, 1 Oct 2023 15:35:42 -0700
Subject: [PATCH] Fix comments getting removed from inside parenthesized
 strings (#3909)

Since the id of the old leaf may be
the key to comments, the new leaf
must adopt the old comments
---
 CHANGES.md                      |  2 ++
 src/black/trans.py              |  3 +++
 tests/data/preview/comments7.py | 24 ++++++++++++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/CHANGES.md b/CHANGES.md
index a879ab3..028a01a 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -17,6 +17,8 @@
 
 <!-- Changes that affect Black's preview style -->
 
+- Fix comments getting removed from inside parenthesized strings (#3909)
+
 ### Configuration
 
 <!-- Changes to how Black can be configured -->
diff --git a/src/black/trans.py b/src/black/trans.py
index daed264..c0cc926 100644
--- a/src/black/trans.py
+++ b/src/black/trans.py
@@ -942,6 +942,9 @@ class StringParenStripper(StringTransformer):
                 LL[lpar_or_rpar_idx].remove()  # Remove lpar.
                 replace_child(LL[idx], string_leaf)
                 new_line.append(string_leaf)
+                # replace comments
+                old_comments = new_line.comments.pop(id(LL[idx]), [])
+                new_line.comments.setdefault(id(string_leaf), []).extend(old_comments)
             else:
                 LL[lpar_or_rpar_idx].remove()  # This is a rpar.
 
diff --git a/tests/data/preview/comments7.py b/tests/data/preview/comments7.py
index 8b12240..0655de9 100644
--- a/tests/data/preview/comments7.py
+++ b/tests/data/preview/comments7.py
@@ -131,6 +131,18 @@ class C:
 
 square = Square(4) # type: Optional[Square]
 
+# Regression test for https://github.com/psf/black/issues/3756.
+[
+    (
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"  # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    ),
+]
+[
+    (  # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"  # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    ),
+]
+
 # output
 
 from .config import (
@@ -282,3 +294,15 @@ class C:
 
 
 square = Square(4)  # type: Optional[Square]
+
+# Regression test for https://github.com/psf/black/issues/3756.
+[
+    (  # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    ),
+]
+[
+    (  # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"  # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    ),
+]
-- 
2.39.2