Issue #15054: Fix incorrect tokenization of 'b' and 'br' string literals.
Patch by Serhiy Storchaka.
diff --git a/Lib/tokenize.py b/Lib/tokenize.py
index ae3de54..1cba6e5 100644
--- a/Lib/tokenize.py
+++ b/Lib/tokenize.py
@@ -70,10 +70,10 @@
Single3 = r"[^'\\]*(?:(?:\\.|'(?!''))[^'\\]*)*'''"
# Tail end of """ string.
Double3 = r'[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*"""'
-Triple = group("[uU]?[rR]?'''", '[uU]?[rR]?"""')
+Triple = group("[uUbB]?[rR]?'''", '[uUbB]?[rR]?"""')
# Single-line ' or " string.
-String = group(r"[uU]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*'",
- r'[uU]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*"')
+String = group(r"[uUbB]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*'",
+ r'[uUbB]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*"')
# Because of leftmost-then-longest match semantics, be sure to put the
# longest operators first (e.g., if = came before ==, == would get
@@ -91,9 +91,9 @@
Token = Ignore + PlainToken
# First (or only) line of ' or " string.
-ContStr = group(r"[uU]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*" +
+ContStr = group(r"[uUbB]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*" +
group("'", r'\\\r?\n'),
- r'[uU]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*' +
+ r'[uUbB]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*' +
group('"', r'\\\r?\n'))
PseudoExtras = group(r'\\\r?\n', Comment, Triple)
PseudoToken = Whitespace + group(PseudoExtras, Number, Funny, ContStr, Name)