from six import PY3, binary_type, text_type

from cryptography.hazmat.bindings.openssl.binding import Binding
binding = Binding()
ffi = binding.ffi
lib = binding.lib

def exception_from_error_queue(exceptionType):
    def text(charp):
        return native(ffi.string(charp))

    errors = []
    while True:
        error = lib.ERR_get_error()
        if error == 0:
            break
        errors.append((
                text(lib.ERR_lib_error_string(error)),
                text(lib.ERR_func_error_string(error)),
                text(lib.ERR_reason_error_string(error))))

    raise exceptionType(errors)



def native(s):
    """
    Convert :py:class:`bytes` or :py:class:`unicode` to the native
    :py:class:`str` type, using UTF-8 encoding if conversion is necessary.

    :raise UnicodeError: The input string is not UTF-8 decodeable.

    :raise TypeError: The input is neither :py:class:`bytes` nor
        :py:class:`unicode`.
    """
    if not isinstance(s, (binary_type, text_type)):
        raise TypeError("%r is neither bytes nor unicode" % s)
    if PY3:
        if isinstance(s, binary_type):
            return s.decode("utf-8")
    else:
        if isinstance(s, text_type):
            return s.encode("utf-8")
    return s



if PY3:
    def byte_string(s):
        return s.encode("charmap")
else:
    def byte_string(s):
        return s

from six import PY3, binary_type, text_type

from cryptography.hazmat.bindings.openssl.binding import Binding
binding = Binding()
ffi = binding.ffi
lib = binding.lib

def exception_from_error_queue(exceptionType):
    def text(charp):
        if not charp:
            return ""
        return native(ffi.string(charp))

    errors = []
    while True:
        error = lib.ERR_get_error()
        if error == 0:
            break
        errors.append((
                text(lib.ERR_lib_error_string(error)),
                text(lib.ERR_func_error_string(error)),
                text(lib.ERR_reason_error_string(error))))

    raise exceptionType(errors)



def native(s):
    """
    Convert :py:class:`bytes` or :py:class:`unicode` to the native
    :py:class:`str` type, using UTF-8 encoding if conversion is necessary.

    :raise UnicodeError: The input string is not UTF-8 decodeable.

    :raise TypeError: The input is neither :py:class:`bytes` nor
        :py:class:`unicode`.
    """
    if not isinstance(s, (binary_type, text_type)):
        raise TypeError("%r is neither bytes nor unicode" % s)
    if PY3:
        if isinstance(s, binary_type):
            return s.decode("utf-8")
    else:
        if isinstance(s, text_type):
            return s.encode("utf-8")
    return s



if PY3:
    def byte_string(s):
        return s.encode("charmap")
else:
    def byte_string(s):
        return s

Handle when an OpenSSL error doesn't contain a reason
Handle when an OpenSSL error doesn't contain a reason

(Or any other field)

You can reproduce the error by running:

```
treq.get('https://nile.ghdonline.org')
```

from within a twisted program (and doing the approrpiate deferred stuff).

I'm unsure how to craft a unit test for this

  from six import PY3, binary_type, text_type
  
  from cryptography.hazmat.bindings.openssl.binding import Binding
  binding = Binding()
  ffi = binding.ffi
  lib = binding.lib
  
  def exception_from_error_queue(exceptionType):
      def text(charp):
+         if not charp:
+             return ""
          return native(ffi.string(charp))
  
      errors = []
      while True:
          error = lib.ERR_get_error()
          if error == 0:
              break
          errors.append((
                  text(lib.ERR_lib_error_string(error)),
                  text(lib.ERR_func_error_string(error)),
                  text(lib.ERR_reason_error_string(error))))
  
      raise exceptionType(errors)
  
  
  
  def native(s):
      """
      Convert :py:class:`bytes` or :py:class:`unicode` to the native
      :py:class:`str` type, using UTF-8 encoding if conversion is necessary.
  
      :raise UnicodeError: The input string is not UTF-8 decodeable.
  
      :raise TypeError: The input is neither :py:class:`bytes` nor
          :py:class:`unicode`.
      """
      if not isinstance(s, (binary_type, text_type)):
          raise TypeError("%r is neither bytes nor unicode" % s)
      if PY3:
          if isinstance(s, binary_type):
              return s.decode("utf-8")
      else:
          if isinstance(s, text_type):
              return s.encode("utf-8")
      return s
  
  
  
  if PY3:
      def byte_string(s):
          return s.encode("charmap")
  else:
      def byte_string(s):
          return s
  
Handle when an OpenSSL error doesn't contain a reason
## Code Before:
from six import PY3, binary_type, text_type

from cryptography.hazmat.bindings.openssl.binding import Binding
binding = Binding()
ffi = binding.ffi
lib = binding.lib

def exception_from_error_queue(exceptionType):
    def text(charp):
        return native(ffi.string(charp))

    errors = []
    while True:
        error = lib.ERR_get_error()
        if error == 0:
            break
        errors.append((
                text(lib.ERR_lib_error_string(error)),
                text(lib.ERR_func_error_string(error)),
                text(lib.ERR_reason_error_string(error))))

    raise exceptionType(errors)



def native(s):
    """
    Convert :py:class:`bytes` or :py:class:`unicode` to the native
    :py:class:`str` type, using UTF-8 encoding if conversion is necessary.

    :raise UnicodeError: The input string is not UTF-8 decodeable.

    :raise TypeError: The input is neither :py:class:`bytes` nor
        :py:class:`unicode`.
    """
    if not isinstance(s, (binary_type, text_type)):
        raise TypeError("%r is neither bytes nor unicode" % s)
    if PY3:
        if isinstance(s, binary_type):
            return s.decode("utf-8")
    else:
        if isinstance(s, text_type):
            return s.encode("utf-8")
    return s



if PY3:
    def byte_string(s):
        return s.encode("charmap")
else:
    def byte_string(s):
        return s

## Instruction:
Handle when an OpenSSL error doesn't contain a reason
## Code After:
from six import PY3, binary_type, text_type

from cryptography.hazmat.bindings.openssl.binding import Binding
binding = Binding()
ffi = binding.ffi
lib = binding.lib

def exception_from_error_queue(exceptionType):
    def text(charp):
        if not charp:
            return ""
        return native(ffi.string(charp))

    errors = []
    while True:
        error = lib.ERR_get_error()
        if error == 0:
            break
        errors.append((
                text(lib.ERR_lib_error_string(error)),
                text(lib.ERR_func_error_string(error)),
                text(lib.ERR_reason_error_string(error))))

    raise exceptionType(errors)



def native(s):
    """
    Convert :py:class:`bytes` or :py:class:`unicode` to the native
    :py:class:`str` type, using UTF-8 encoding if conversion is necessary.

    :raise UnicodeError: The input string is not UTF-8 decodeable.

    :raise TypeError: The input is neither :py:class:`bytes` nor
        :py:class:`unicode`.
    """
    if not isinstance(s, (binary_type, text_type)):
        raise TypeError("%r is neither bytes nor unicode" % s)
    if PY3:
        if isinstance(s, binary_type):
            return s.decode("utf-8")
    else:
        if isinstance(s, text_type):
            return s.encode("utf-8")
    return s



if PY3:
    def byte_string(s):
        return s.encode("charmap")
else:
    def byte_string(s):
        return s
