usCodePageRange Macintosh Character Set (US Roman) (bit 29) is not saved as an integer in the Glyphs source and causes an error

[kalapi]

I'm getting the following error when I try to run fontmake 3.7.1 on a Glyphs 3.1.2 (3151) source:

fontmake: Error: In '~/Meursault.glyphs': Loading Glyphs file failed: invalid literal for int() with base 10: 'bit 29'

A bit of a background

The codePageRanges custom parameter in Glyphs 2 did not include support for bit 29: Macintosh Character Set (US Roman). As a result, a trick to enable it was to open the source file in a text editor and add "bit 29" manually as a value in the codePageRanges key in the XML like so:

{
name = codePageRanges;
value = (
"1252",
"1250",
"1254",
"1257",
"1258",
"bit 29"
);
}

In Glyphs 3, support for the missing codepage has been added and it seems that for backward compatibility purposes instead of using an integer value, the value remains a string which raises:

File "~/testing_environments/FMake37/lib/python3.8/site-packages/glyphsLib/types.py", line 356, in _mutate_list
    l[i] = fn(l[i])
ValueError: invalid literal for int() with base 10: 'bit 29'

What would be the best way to handle this?

[anthrotype]

ugh... hi kalapi! thanks for the report. I think glyphsLib should take care of this for fontmake. I'll see if I can transfer the issue.

[anthrotype]

looks like this is a duplicate of https://github.com/googlefonts/glyphsLib/issues/530 and https://github.com/googlefonts/glyphsLib/issues/807