From 37b838ff293dc2147dc4c263f7cbfb5e35311641 Mon Sep 17 00:00:00 2001
From: Henri Holopainen <henri.i.holopainen@gmail.com>
Date: Tue, 31 Oct 2023 14:07:15 +0200
Subject: [PATCH 1/4] Add test case

---
 tests/data/cases/docstring.py | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tests/data/cases/docstring.py b/tests/data/cases/docstring.py
index c31d6a68783..e983c5bd438 100644
--- a/tests/data/cases/docstring.py
+++ b/tests/data/cases/docstring.py
@@ -221,6 +221,12 @@ def stable_quote_normalization_with_immediate_inner_single_quote(self):
     '''
 
 
+def foo():
+    """
+    Docstring with a backslash followed by a space\ 
+    and then another line
+    """
+
 # output
 
 class MyClass:
@@ -442,3 +448,10 @@ def stable_quote_normalization_with_immediate_inner_single_quote(self):
 
     <text here, since without another non-empty line black is stable>
     """
+
+
+def foo():
+    """
+    Docstring with a backslash followed by a space\ 
+    and then another line
+    """

From 392d693b7c5f7d8752d77a2bab999dc4244da172 Mon Sep 17 00:00:00 2001
From: Henri Holopainen <henri.i.holopainen@gmail.com>
Date: Tue, 31 Oct 2023 14:17:14 +0200
Subject: [PATCH 2/4] Don't format docstrings that end with backslash followed
 by whitespace(s)

---
 src/black/linegen.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/black/linegen.py b/src/black/linegen.py
index 43bc08efbbd..121c6e314fe 100644
--- a/src/black/linegen.py
+++ b/src/black/linegen.py
@@ -2,6 +2,7 @@
 Generating lines of code.
 """
 
+import re
 import sys
 from dataclasses import replace
 from enum import Enum, auto
@@ -420,7 +421,7 @@ def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
         if Preview.hex_codes_in_unicode_sequences in self.mode:
             normalize_unicode_escape_sequences(leaf)
 
-        if is_docstring(leaf) and "\\\n" not in leaf.value:
+        if is_docstring(leaf) and not re.search(r"\\\s*\n", leaf.value):
             # We're ignoring docstrings with backslash newline escapes because changing
             # indentation of those changes the AST representation of the code.
             if self.mode.string_normalization:

From 42ed17eb7c4959c6fe2b15618e859aa400545446 Mon Sep 17 00:00:00 2001
From: Henri Holopainen <henri.i.holopainen@gmail.com>
Date: Tue, 31 Oct 2023 14:17:32 +0200
Subject: [PATCH 3/4] Add changelog line

---
 CHANGES.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/CHANGES.md b/CHANGES.md
index dd5f52cf706..d5bcee7bc60 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -8,7 +8,8 @@
 
 ### Stable style
 
-<!-- Changes that affect Black's stable style -->
+- Fix a crash when whitespace(s) followed a backslash before newline in a docstring
+  (#XXXX)
 
 ### Preview style
 

From 0da28a62b3c1194c41d8764d81bcee41804cbdbc Mon Sep 17 00:00:00 2001
From: Henri Holopainen <henri.i.holopainen@gmail.com>
Date: Tue, 31 Oct 2023 14:23:53 +0200
Subject: [PATCH 4/4] Update PR number

---
 CHANGES.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGES.md b/CHANGES.md
index d5bcee7bc60..e910fbed162 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -9,7 +9,7 @@
 ### Stable style
 
 - Fix a crash when whitespace(s) followed a backslash before newline in a docstring
-  (#XXXX)
+  (#4008)
 
 ### Preview style