From 91107fe78a290a7d25a042fec09ea89f14f480d9 Mon Sep 17 00:00:00 2001
From: xuhuijie <[email protected]>
Date: Wed, 16 Jun 2021 15:47:22 +0800
Subject: [PATCH] regex: fix dead loop in parse_repea 
 There is a bug in parse_repeat(), after deal with comment the
 contin value will be always true. So we enter a dead loop. To deal with this,
 we assign contin to false each time we enter the loop.
 Testcase: boost::regex(std::string("1?+(?#)1"))

Signed-off-by: Xu Huijie <[email protected]>
---
 boost/regex/v4/basic_regex_parser.hpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/boost/regex/v4/basic_regex_parser.hpp b/boost/regex/v4/basic_regex_parser.hpp
index 6c7065f05..de22f7000 100644
--- a/boost/regex/v4/basic_regex_parser.hpp
+++ b/boost/regex/v4/basic_regex_parser.hpp
@@ -1080,9 +1080,10 @@ bool basic_regex_parser<charT, traits>::parse_repeat(std::size_t low, std::size_
          // Check for illegal following quantifier, we have to do this here, because
          // the extra states we insert below circumvents our usual error checking :-(
          //
-         bool contin = false;
+         bool contin;
          do
          {
+            contin = false;
             if ((this->flags() & (regbase::main_option_type | regbase::mod_x | regbase::no_perl_ex)) == regbase::mod_x)
             {
                // whitespace skip:
-- 
2.23.0