example.py

# match greedy level 0
a = '%s' % '123'

# match greedy level 1
b = ('x' + '%s') % '123'

c = '%s'
# match greedy level 2
d = c % '123'

# false positive greedy level 1
e = '' + str(3 % 2)

# false positive greedy level 2
f = 3 % 2

# match greedy level 0
g = '{val}'.format(val=123)

# match greedy level 1
h = ('x' + '{}').format(123)

i = '{}'
# match greedy level 2
j = i.format(123)


class C:
    def format(self):  # noqa: A003
        return ''


# false positive greedy level 1
k = '' + C().format()

# false positive greedy level 2
m = C().format()

# missing prefix false positive
n = (rf'{m}'
     '{'
     '}'
     'm'
     ''
     '{}'
     '{{m}}')

# match missing prefix
o = ('{n}'
     '{{m}} {n}'
     r'[a-z]{1,3}')  # Should not be matched.

# should not be matched on any greedy level < 2
# (bytestrings can't be f-strings)
p = b'%d' % f

# should not be matched for missing prefix
# (bytestrings can't be f-strings)
q = b'{n}'

# no errors below; coverage
''.strip()