[GRASS-dev] [GRASS GIS] #2532: TypeError: environment can only contain string when launching script on Windows

GRASS GIS trac at osgeo.org
Tue Jan 20 15:22:53 PST 2015

#2532: TypeError: environment can only contain string when launching script on
 Reporter:  annakrat     |       Owner:  grass-dev@…              
     Type:  defect       |      Status:  new                      
 Priority:  normal       |   Milestone:  7.0.0                    
Component:  Default      |     Version:  svn-trunk                
 Keywords:  encoding     |    Platform:  MSWindows 8              
      Cpu:  Unspecified  |  

Comment(by glynn):

 Replying to [comment:15 annakrat]:

 > No, when I print the string I get xml, seems to be valid:
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE task SYSTEM "C:\Users\akratoc\Programs\GRASS GIS 7.1.svn\gui\xml
 <task name="test_workshopá.py">
 > I don't understand what's wrong with it.

 The name= attribute will fail to decode due to not being valid UTF-8. The
 "á" will be encoded in cp1252 (i.e. '\xe1'); attempting to decode that as
 UTF-8 will fail (non-ASCII characters are encoded as multi-byte sequences;
 an isolated byte >= 128 can never occur in UTF-8).

 > > In any case, the GUI should be encoding the arguments which it passes
 to Popen(); it shouldn't be passing unicode values.
 > Should the be encoding moved to `get_interface_description` in task.py?

 No. The GUI shouldn't be passing unicode values to the grass.script
 library; it should be converting them to strings itself.

 > The `EncodeString` function is in gui, not in python scripting library.

 grass.script.core has encode() and decode().

 > If I try to run the script (this time the script name is only ascii, but
 the path has some non-ascii characters which are in cp1252), I get the gui
 dialog and when I run it, I get an error:
   File "C:\Users\akratoc\Programs\GRASS GIS
 7.1.svn\gui\wxpython\core\gcmd.py", line 92, in EncodeString
     return string.encode(_enc)
   File "C:\Users\akratoc\Programs\GRASS GIS
 7.1.svn\Python27\lib\encodings\cp1252.py", line 12, in
 UnicodeDecodeError: 'ascii' codec can't decode byte 0xe1 in
 position 38: ordinal not in range(128)

 Ugh. I couldn't figure out what was happening here until I read the next
 sentence. It appears that str.encode() actually exists; it tries to
 convert the string to unicode (using the default encoding) so that it can
 encode it.

 > because in Popen class in
 gcmd.py] some of the arguments are of type `str`, some are `unicode`. So
 if encode only the unicode ones, it starts to work.

 That makes sense. But the encoding should ideally be done at a higher
 level, at the point that wxGUI "knows" that it's dealing with a unicode

 This is the main reason why I dislike dynamically-typed languages for
 large-scale projects (I'd never have suggested Python if I'd have known
 that wxGUI was going to turn into such a behemoth). In C/C++, you'd just
 get a compile error if you pass a wchar_t*/std::wstring() where a
 char*/std::string was expected. In Python, you get something which appears
 to work until it starts getting decent test coverage.

 I'm wondering if sys.setdefaultencoding("EBCDIC-CP-BE") would work ...

Ticket URL: <http://trac.osgeo.org/grass/ticket/2532#comment:16>
GRASS GIS <http://grass.osgeo.org>

More information about the grass-dev mailing list