Issue with subclasses now no longer using isinstance

I am using django so some of my strings are subclasses of str, more specifically they are SafeText instances. This means that the changes to speed up the write method no longer do isinstance checks and instead check the content passed though are actual str types. Unfortunately this makes the library less pythonic (“if it quacks like a duck…”). Further, apart from not writing this as a string to the workbook it also uncovers an issue where unicode is no longer a keyword in python 3 and so I get the below stack trace.

I am using Python version 3.6 and XlsxWriter 1.0.6

Here is some code that demonstrates the problem:

In [3]: class MyStr(str):
   ...:     pass
   ...:
   ...:

In [4]: import xlsxwriter

In [5]: workbook = xlsxwriter.Workbook('hello.xlsx')

In [6]: worksheet = workbook.add_worksheet()

In [7]: worksheet.write('A1', MyStr('Hello world'))
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-7-ba253f798a36> in <module>()
----> 1 worksheet.write('A1', MyStr('Hello world'))

~/.local/share/virtualenvs/AgricolaWeb-bDFxwp9T/lib/python3.7/site-packages/xlsxwriter/worksheet.py in cell_wrapper(self, *args, **kwargs)
     64             args = new_args + args[1:]
     65
---> 66         return method(self, *args, **kwargs)
     67
     68     return cell_wrapper

~/.local/share/virtualenvs/AgricolaWeb-bDFxwp9T/lib/python3.7/site-packages/xlsxwriter/worksheet.py in write(self, row, col, *args)
    402
    403         """
--> 404         return self._write(row, col, *args)
    405
    406     # Undecorated version of write().

~/.local/share/virtualenvs/AgricolaWeb-bDFxwp9T/lib/python3.7/site-packages/xlsxwriter/worksheet.py in _write(self, row, col, *args)
    435             return self._write_datetime(row, col, *args)
    436
--> 437         if token_type is unicode:
    438             try:
    439                 return self._write_token_as_string(str(token), row, col, *args)

NameError: name 'unicode' is not defined

In [8]: isinstance(MyStr('Hello world'), str)
Out[8]: True

In the meantime I will pin to 1.0.5 as that is simpler than going though and figuring out if all the places I pass strings to get written are subclasses of str.

[jmcnamara]

Thanks for the report. Definitely a bug. I’ll revert the unicode part of the change and release an update in the next 12 hours.

@percious Any comments?

[jmcnamara]

Test and fixed on 29b411b