Importing svg2tikz in Pyzo causes exception, works fine in the terminal

[ysalmon]

Hi, I stumbled upon a failure with svg2tikz master in Pyzo : xyz2tex/svg2tikz#144

Setting up en venv with the bare minimum to have svg2tikz code from their master branch, and creating a shell in Pyzo to use that venv, causes

>>> import svg2tikz
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/tmp/v2/lib/python3.10/site-packages/svg2tikz/__init__.py", line 1, in <module>
    from .tikz_export import convert_file, convert_svg
  File "/tmp/v2/lib/python3.10/site-packages/svg2tikz/tikz_export.py", line 383, in <module>
    class TikZPathExporter(inkex.Effect, inkex.EffectExtension):
  File "/tmp/v2/lib/python3.10/site-packages/svg2tikz/tikz_export.py", line 1340, in TikZPathExporter
    def run(self, args=None, output=sys.stdout.buffer):
AttributeError: 'FileWrapper' object has no attribute 'buffer'

Opening a terminal and doing

. /tmp/v2/bin/activate
python
import svg2tikz

gives no error.

However, their latest release, which of course predates their master, does not exhibit this problem in pyzo.

I suspect a strange interaction between the two…

[bdieterm]

Hi @ysalmon!
The error means that sys.stdout has not buffer attribute.
This is because Pyzo replaces sys.stdout with a yoton FileWrapper object (see pyzo/yoton/channels/channels_file.py and pyzo/pyzokernel/start.py) in order to communicate between the Python kernel and the Pyzo main application.
Implementing a buffer substitute in the yoton FileWrapper class would be possible but complicated because communication between the kernel and Pyzo is supposed to be via utf-8 strings and not random raw bytes. And the next problem would be to properly display that random bytes (that might not be mapped to utf-8 characters) in the shell in Pyzo via the QPlainTextEdit widget.

As far as I have seen, sys.stdout.buffer as a default parameter value was introduced around two weeks after the current release -- see xyz2tex/svg2tikz#126

I only had a quick look at the code. This stdout buffer seems to be intended to be used when running svg2tikz with command line arguments in a terminal and piping the result from stdout to another tool.

I guess, since you are importing svg2tikz in a shell within Pyzo, that you are not using the command line arguments with that module. In this case you could do a simple workaround. Just set the stdout buffer to None before importing the module:

sys.stdout.buffer = None
import svg2tikz

If you do not want to modify (existing) source codes, then you could also add sys.stdout.buffer = None to the "startupScript" textbox in the Pyzo shell configuration dialog.

[ldevillez]

Fixed in svg2tikz 👍