From 711156629f3ddca81f7c33c0307e1eaf32f27f84 Mon Sep 17 00:00:00 2001
From: tpcwang <tpc.wang@gmail.com>
Date: Wed, 23 Mar 2016 15:22:33 -0700
Subject: [PATCH] Fix TDebugProtocol::writeString to avoid assertion in isprint

---
 lib/cpp/src/thrift/protocol/TDebugProtocol.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/cpp/src/thrift/protocol/TDebugProtocol.cpp b/lib/cpp/src/thrift/protocol/TDebugProtocol.cpp
index 4687e82f832..09b978c2d7f 100644
--- a/lib/cpp/src/thrift/protocol/TDebugProtocol.cpp
+++ b/lib/cpp/src/thrift/protocol/TDebugProtocol.cpp
@@ -347,7 +347,9 @@ uint32_t TDebugProtocol::writeString(const string& str) {
       output += "\\\\";
     } else if (*it == '"') {
       output += "\\\"";
-    } else if (std::isprint(*it)) {
+      // passing characters <0 to std::isprint causes asserts. isprint takes an
+      // int, so we need to be careful of sign extension
+    } else if (std::isprint((unsigned char)*it)) {
       output += *it;
     } else {
       switch (*it) {