Python 2.7 and "from __future__ import unicode_literals" causes UnicodeEncodeError #2276
Description
I have some very strange UnicodeEncodeError in my application. I could reduce the problem to the following example:
from __future__ import unicode_literals
deg = u'\u00B0'
'%s%s' % ('15', deg)
When I compile this example with cython>=0.28.0 and run is with Python 2.7.14 I get the following error:
C:\tmp\python
Python 2.7.14 (v2.7.14:84471935ed, Sep 16 2017, 20:25:58) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import crash
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "crash.pyx", line 3, in init crash
'%s%s' % ('15', deg)
UnicodeEncodeError: 'ascii' codec can't encode character u'\xb0' in position 0: ordinal not in range(128)
Using cython==0.27.3 there is no such error and the example works fine.
By looking at the code it seems the "PyObject_Str" statement causes the problem. However I have no idea how to fix the issue except for using cython 0.27.3 for python 2.7.
/* "crash.pyx":3
* from __future__ import unicode_literals
* deg = u'\u00B0'
* '%s%s' % ('15', deg) # <<<<<<<<<<<<<<
*/
__Pyx_GetModuleGlobalName(__pyx_t_1, __pyx_n_s_deg); if (unlikely(!__pyx_t_1)) __PYX_ERR(0, 3, __pyx_L1_error)
__Pyx_GOTREF(__pyx_t_1);
__pyx_t_2 = __Pyx_PyObject_FormatSimpleAndDecref(PyObject_Str(__pyx_t_1), __pyx_empty_unicode); if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 3, __pyx_L1_error)
__Pyx_GOTREF(__pyx_t_2);
__Pyx_DECREF(__pyx_t_1); __pyx_t_1 = 0;
__pyx_t_1 = __Pyx_PyUnicode_Concat(__pyx_kp_u_15, __pyx_t_2); if (unlikely(!__pyx_t_1)) __PYX_ERR(0, 3, __pyx_L1_error)
__Pyx_GOTREF(__pyx_t_1);
__Pyx_DECREF(__pyx_t_2); __pyx_t_2 = 0;
__Pyx_DECREF(__pyx_t_1); __pyx_t_1 = 0;