Re: [PATCH] gnulib-tool.py: Inline 'sed' invocations used on library files.

[Collin Funk]

On 3/27/24 6:24 PM, Bruno Haible wrote:
> Thanks! Applied, with one tweak: Let's continue to use 'rb' and 'wb' as
> file open() modes, not 'r' and 'w'. If gnulib-tool ever gets used on
> Windows, we don't want the trouble caused by Windows CRLF newlines.
> We want all generated files to use Unix LF newlines. (Some of the
> constants.nlconvert nonsense will have to go away as well.)

Oops, I've been using the the standard open() function since I'm not
too familiar with the 'codecs' module. I believe they work a bit
differently.

With open() using binary mode with encoding='utf-8' causes a failure:

     with open('test.txt', 'wb', encoding='utf-8') as file:
         file.write('abc')

     Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
     ValueError: binary mode doesn't take an encoding argument

The default encoding if not passed is None. I use it since the default
encoding is None. I assume in that case it is left up to the operating
system. I know previous versions of Windows liked UTF-16, but maybe it
is different now.

The codecs module doesn't seem to have that restriction, but Python
says that the regular open() and 'io' module should be used for text
files [1].

>From the documentation from open, it seems the best way to deal with
this is for reading files [2]:

     # Accepts '\n', '\r', '\r\n' as newline.
     with open('file.txt', 'r', encoding='utf-8') as file:
          data = file.read()

And then for writing files:

    # Write files with '\n' as newline character.
    with open('file.txt', 'w', encoding='utf-8', newline='\n') as file:
         file.write(data)

These changes are pretty simple though. I can get a Windows virtual
machine running at some point to test these changes.

[1] https://docs.python.org/3/library/functions.html#open
[2] https://docs.python.org/3/library/functions.html#open

Collin