From 13bd0925eb347926399a5bcb8b70853549f3da07 Mon Sep 17 00:00:00 2001
From: cobalt <61329810+RedGuy12@users.noreply.github.com>
Date: Fri, 22 Mar 2024 21:11:01 -0500
Subject: [PATCH] fix: Stop moving multiline strings to a new line unless
 inside brackets (#4289)

Signed-off-by: RedGuy12 <61329810+RedGuy12@users.noreply.github.com>
---
 CHANGES.md                                    |  1 +
 src/black/lines.py                            |  6 ++++--
 tests/data/cases/preview_multiline_strings.py | 14 ++++++++++++++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 12a2d5fa064..e6098b7ff59 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -16,6 +16,7 @@
 
 - `if` guards in `case` blocks are now wrapped in parentheses when the line is too long.
   (#4269)
+- Stop moving multiline strings to a new line unless inside brackets (#4289)
 
 ### Configuration
 
diff --git a/src/black/lines.py b/src/black/lines.py
index 72634fd36d2..6b65372fb3f 100644
--- a/src/black/lines.py
+++ b/src/black/lines.py
@@ -858,11 +858,13 @@ def is_line_short_enough(  # noqa: C901
                     return False
 
         if leaf.bracket_depth <= max_level_to_update and leaf.type == token.COMMA:
-            # Ignore non-nested trailing comma
+            # Inside brackets, ignore trailing comma
             # directly after MLS/MLS-containing expression
             ignore_ctxs: List[Optional[LN]] = [None]
             ignore_ctxs += multiline_string_contexts
-            if not (leaf.prev_sibling in ignore_ctxs and i == len(line.leaves) - 1):
+            if (line.inside_brackets or leaf.bracket_depth > 0) and (
+                i != len(line.leaves) - 1 or leaf.prev_sibling not in ignore_ctxs
+            ):
                 commas[leaf.bracket_depth] += 1
         if max_level_to_update != math.inf:
             max_level_to_update = min(max_level_to_update, leaf.bracket_depth)
diff --git a/tests/data/cases/preview_multiline_strings.py b/tests/data/cases/preview_multiline_strings.py
index 9288f6991bd..1daf6f4d784 100644
--- a/tests/data/cases/preview_multiline_strings.py
+++ b/tests/data/cases/preview_multiline_strings.py
@@ -175,6 +175,13 @@ def dastardly_default_value(
     "c"
 )
 
+assert some_var == expected_result, """
+test
+"""
+assert some_var == expected_result, f"""
+expected: {expected_result}
+actual: {some_var}"""
+
 # output
 """cow
 say""",
@@ -385,3 +392,10 @@ def dastardly_default_value(
 )
 
 this_will_also_become_one_line = "abc"  # comment
+
+assert some_var == expected_result, """
+test
+"""
+assert some_var == expected_result, f"""
+expected: {expected_result}
+actual: {some_var}"""