From 539bc017a62f91bdf7c547b58948cb5a2f59d918 Mon Sep 17 00:00:00 2001
From: Ben Webb <ben@salilab.org>
Date: Thu, 12 Jul 2018 10:58:10 -0700
Subject: [PATCH] Add Python 3.7 compatibility (#4862)

Compilation of Python wrappers fails with Python 3.7 because
the Python folks changed their C API such that
PyUnicode_AsUTF8AndSize() now returns a const char* rather
than a char*. Add a patch to work around. Relates #4086.
---
 python/google/protobuf/pyext/descriptor.cc            | 2 +-
 python/google/protobuf/pyext/descriptor_containers.cc | 2 +-
 python/google/protobuf/pyext/descriptor_pool.cc       | 2 +-
 python/google/protobuf/pyext/extension_dict.cc        | 2 +-
 python/google/protobuf/pyext/message.cc               | 4 ++--
 5 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/python/google/protobuf/pyext/descriptor.cc b/python/google/protobuf/pyext/descriptor.cc
index 8af0cb1289..19a1c38a62 100644
--- a/python/google/protobuf/pyext/descriptor.cc
+++ b/python/google/protobuf/pyext/descriptor.cc
@@ -56,7 +56,7 @@
   #endif
   #define PyString_AsStringAndSize(ob, charpp, sizep) \
     (PyUnicode_Check(ob)? \
-       ((*(charpp) = PyUnicode_AsUTF8AndSize(ob, (sizep))) == NULL? -1: 0): \
+       ((*(charpp) = const_cast<char*>(PyUnicode_AsUTF8AndSize(ob, (sizep)))) == NULL? -1: 0): \
        PyBytes_AsStringAndSize(ob, (charpp), (sizep)))
 #endif

diff --git a/python/google/protobuf/pyext/descriptor_containers.cc b/python/google/protobuf/pyext/descriptor_containers.cc
index bc007f7efa..0153664f50 100644
--- a/python/google/protobuf/pyext/descriptor_containers.cc
+++ b/python/google/protobuf/pyext/descriptor_containers.cc
@@ -66,7 +66,7 @@
   #endif
   #define PyString_AsStringAndSize(ob, charpp, sizep) \
     (PyUnicode_Check(ob)? \
-       ((*(charpp) = PyUnicode_AsUTF8AndSize(ob, (sizep))) == NULL? -1: 0): \
+       ((*(charpp) = const_cast<char*>(PyUnicode_AsUTF8AndSize(ob, (sizep)))) == NULL? -1: 0): \
        PyBytes_AsStringAndSize(ob, (charpp), (sizep)))
 #endif

diff --git a/python/google/protobuf/pyext/descriptor_pool.cc b/python/google/protobuf/pyext/descriptor_pool.cc
index 95882aeb35..962accc6e9 100644
--- a/python/google/protobuf/pyext/descriptor_pool.cc
+++ b/python/google/protobuf/pyext/descriptor_pool.cc
@@ -48,7 +48,7 @@
   #endif
   #define PyString_AsStringAndSize(ob, charpp, sizep) \
     (PyUnicode_Check(ob)? \
-       ((*(charpp) = PyUnicode_AsUTF8AndSize(ob, (sizep))) == NULL? -1: 0): \
+       ((*(charpp) = const_cast<char*>(PyUnicode_AsUTF8AndSize(ob, (sizep)))) == NULL? -1: 0): \
        PyBytes_AsStringAndSize(ob, (charpp), (sizep)))
 #endif

diff --git a/python/google/protobuf/pyext/extension_dict.cc b/python/google/protobuf/pyext/extension_dict.cc
index 018b5c2c49..174c5470c2 100644
--- a/python/google/protobuf/pyext/extension_dict.cc
+++ b/python/google/protobuf/pyext/extension_dict.cc
@@ -53,7 +53,7 @@
   #endif
   #define PyString_AsStringAndSize(ob, charpp, sizep) \
     (PyUnicode_Check(ob)? \
-       ((*(charpp) = PyUnicode_AsUTF8AndSize(ob, (sizep))) == NULL? -1: 0): \
+       ((*(charpp) = const_cast<char*>(PyUnicode_AsUTF8AndSize(ob, (sizep)))) == NULL? -1: 0): \
        PyBytes_AsStringAndSize(ob, (charpp), (sizep)))
 #endif

diff --git a/python/google/protobuf/pyext/message.cc b/python/google/protobuf/pyext/message.cc
index 5893533adf..31094b7e10 100644
--- a/python/google/protobuf/pyext/message.cc
+++ b/python/google/protobuf/pyext/message.cc
@@ -79,7 +79,7 @@
     (PyUnicode_Check(ob)? PyUnicode_AsUTF8(ob): PyBytes_AsString(ob))
   #define PyString_AsStringAndSize(ob, charpp, sizep) \
     (PyUnicode_Check(ob)? \
-       ((*(charpp) = PyUnicode_AsUTF8AndSize(ob, (sizep))) == NULL? -1: 0): \
+       ((*(charpp) = const_cast<char*>(PyUnicode_AsUTF8AndSize(ob, (sizep)))) == NULL? -1: 0): \
        PyBytes_AsStringAndSize(ob, (charpp), (sizep)))
   #endif
 #endif
@@ -1529,7 +1529,7 @@ PyObject* HasField(CMessage* self, PyObject* arg) {
     return NULL;
   }
 #else
-  field_name = PyUnicode_AsUTF8AndSize(arg, &size);
+  field_name = const_cast<char*>(PyUnicode_AsUTF8AndSize(arg, &size));
   if (!field_name) {
     return NULL;
   }
