agronholm / typeguard / 262

95%

push

travis-ci-com

Correctly match package/module names in import hook (#144)

The previously used regular expression tried to handle both exact
matches and and prefix matches in one go, using this approach:

    re.compile(r'^%s\.?' % pkg)

However, this is incorrect, since the literal dot is optional in the
pattern, causing longer matches to also get included. For example, ‘foo’
should match ‘foo’ and ‘foo.bar’, but it also incorrectly matches
‘foobar’:

    >>> re.compile(r'^foo\.?').match('foobar')
    <_sre.SRE_Match object; span=(0, 3), match='foo'>

In practice, a command like this (using the pytest plugin as an example)
is supposed to check the ‘flask’ package and any modules below it:

    pytest --typeguard-packages=flask

... but in reality it also checks other packages, such as
‘flask_sqlalchemy’ and ‘flask_redis’, if those happen to be installed.

This can be easily fixed by not using regular expression, but simple
string matching instead.

3 of 3 new or added lines in 1 file covered. (100.0%)

598 of 675 relevant lines covered (88.59%)

3.47 hits per line