Bug#950103: fonts-lemonada FTBFS: KeyError: "glyph 'M' already exists"

[Adrian Bunk <bunk@debian.org>]

Source: fonts-lemonada
Version: 4.004+git20190612-1
Severity: serious
Tags: ftbfs

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/fonts-lemonada.html

...
   debian/rules override_dh_auto_build
make[1]: Entering directory '/build/1st/fonts-lemonada-4.004+git20190612'
fontmake -i -o otf -g sources/*.glyphs
INFO:fontmake.font_project:Building master UFOs and designspace from Glyphs source
INFO:glyphsLib.classes:Parsing "sources/Lemonada.glyphs" file into <GSFont>
Traceback (most recent call last):
  File "/usr/bin/fontmake", line 11, in <module>
    load_entry_point('fontmake==2.0.7', 'console_scripts', 'fontmake')()
  File "/usr/lib/python3/dist-packages/fontmake/__main__.py", line 425, in main
    project.run_from_glyphs(glyphs_path, **args)
  File "/usr/lib/python3/dist-packages/fontmake/font_project.py", line 670, in run_from_glyphs
    write_skipexportglyphs=write_skipexportglyphs,
  File "/usr/lib/python3/dist-packages/fontTools/misc/loggingTools.py", line 367, in wrapper
    return func(*args, **kwds)
  File "/usr/lib/python3/dist-packages/fontmake/font_project.py", line 156, in build_master_ufos
    ufo_module=ufoLib2,
  File "/usr/lib/python3/dist-packages/glyphsLib/builder/__init__.py", line 111, in to_designspace
    return builder.designspace
  File "/usr/lib/python3/dist-packages/glyphsLib/builder/builders.py", line 260, in designspace
    list(self.masters)  # Make sure that the UFOs are built
  File "/usr/lib/python3/dist-packages/glyphsLib/builder/builders.py", line 222, in masters
    ufo_glyph = ufo_layer.newGlyph(glyph.name)
  File "/usr/lib/python3/dist-packages/ufoLib2/objects/layer.py", line 120, in newGlyph
    raise KeyError("glyph %r already exists" % name)
KeyError: "glyph 'M' already exists"
make[1]: *** [debian/rules:12: override_dh_auto_build] Error 1