FileNotFoundError for not existing file

[marxin]

Sometimes gcov creates .gcov files that don't have a source file (a typical example is a .l lexer file):

gcov a-test.c
File 'foooo.c'
Lines executed:100.00% of 2
Creating 'foooo.c.gcov'
Cannot open source file foooo.c

Lines executed:100.00% of 2

where foooo.c.gcov contains:

cat foooo.c.gcov
        -:    0:Source:foooo.c
        -:    0:Graph:a-test.gcno
        -:    0:Data:a-test.gcda
        -:    0:Runs:1

and coverall crashes:

coveralls 
Traceback (most recent call last):
  File "/home/marxin/.local/bin/coveralls", line 8, in <module>
    sys.exit(run())
  File "/home/marxin/.local/lib/python3.8/site-packages/cpp_coveralls/__init__.py", line 97, in run
    cov_report = coverage.collect(args)
  File "/home/marxin/.local/lib/python3.8/site-packages/cpp_coveralls/coverage.py", line 455, in collect
    with io.open(source_file_path, mode='rb') as src_file:
FileNotFoundError: [Errno 2] No such file or directory: '/home/marxin/Programming/testcases/sample/foooo.c'