From 8163f2dced27bc91cd756b1af8a958d714e1deff Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Mon, 30 Oct 2023 07:37:20 -0700
Subject: [PATCH 1/2] Fix bytes strings being treated as docstrings

Fixes #4002

I think this only fixes crashes so it doesn't need to go through the preview style,
but not 100% sure.
---
 CHANGES.md                              |  2 +-
 src/black/nodes.py                      |  9 ++++++-
 tests/data/cases/bytes_docstring.py     | 34 +++++++++++++++++++++++++
 tests/data/{ => cases}/raw_docstring.py |  0
 4 files changed, 43 insertions(+), 2 deletions(-)
 create mode 100644 tests/data/cases/bytes_docstring.py
 rename tests/data/{ => cases}/raw_docstring.py (100%)

diff --git a/CHANGES.md b/CHANGES.md
index 60231468bdf..4d5b30f56b9 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -8,7 +8,7 @@
 
 ### Stable style
 
-<!-- Changes that affect Black's stable style -->
+- Fix crash on formatting bytes strings that look like docstrings (#4003)
 
 ### Preview style
 
diff --git a/src/black/nodes.py b/src/black/nodes.py
index b2e96cb9edf..5f6b280c035 100644
--- a/src/black/nodes.py
+++ b/src/black/nodes.py
@@ -14,7 +14,7 @@
 
 from black.cache import CACHE_DIR
 from black.mode import Mode, Preview
-from black.strings import has_triple_quotes
+from black.strings import get_string_prefix, has_triple_quotes
 from blib2to3 import pygram
 from blib2to3.pgen2 import token
 from blib2to3.pytree import NL, Leaf, Node, type_repr
@@ -525,6 +525,13 @@ def is_arith_like(node: LN) -> bool:
 
 
 def is_docstring(leaf: Leaf) -> bool:
+    if leaf.type != token.STRING:
+        return False
+
+    prefix = get_string_prefix(leaf.value)
+    if "b" in prefix or "B" in prefix:
+        return False
+
     if prev_siblings_are(
         leaf.parent, [None, token.NEWLINE, token.INDENT, syms.simple_stmt]
     ):
diff --git a/tests/data/cases/bytes_docstring.py b/tests/data/cases/bytes_docstring.py
new file mode 100644
index 00000000000..2326e95293a
--- /dev/null
+++ b/tests/data/cases/bytes_docstring.py
@@ -0,0 +1,34 @@
+def bitey():
+    b" not a docstring"
+
+def bitey2():
+    b' also not a docstring'
+
+def triple_quoted_bytes():
+    b""" not a docstring"""
+
+def triple_quoted_bytes2():
+    b''' also not a docstring'''
+
+def capitalized_bytes():
+    B" NOT A DOCSTRING"
+
+# output
+def bitey():
+    b" not a docstring"
+
+
+def bitey2():
+    b" also not a docstring"
+
+
+def triple_quoted_bytes():
+    b""" not a docstring"""
+
+
+def triple_quoted_bytes2():
+    b""" also not a docstring"""
+
+
+def capitalized_bytes():
+    b" NOT A DOCSTRING"
\ No newline at end of file
diff --git a/tests/data/raw_docstring.py b/tests/data/cases/raw_docstring.py
similarity index 100%
rename from tests/data/raw_docstring.py
rename to tests/data/cases/raw_docstring.py

From d5fd14d4903805c4cf823468f9daee06fca1494f Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 31 Oct 2023 23:56:44 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 CHANGES.md | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 269a32b1bb4..f365f1c239b 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -9,8 +9,7 @@
 ### Stable style
 
 - Fix crash on formatting bytes strings that look like docstrings (#4003)
-- Fix crash when whitespace followed a backslash before newline in a docstring
-  (#4008)
+- Fix crash when whitespace followed a backslash before newline in a docstring (#4008)
 
 ### Preview style