Basic support for requirements.txt file

LICENSE.txt

@@ -1,6 +1,6 @@
 The MIT License
 
-Copyright (c) 2017 Arkadiusz Bokowy <[email protected]>
+Copyright (c) 2017-2018 Arkadiusz Bokowy <[email protected]>
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.rst

@@ -14,7 +14,8 @@ Important notice
 
 In order to collect project's dependencies, this checker evaluates Python code from the
 ``setup.py`` file stored in the project's root directory. Code evaluation is done with the
-`eval() <https://docs.python.org/3/library/functions.html#eval>`_ function.
+`eval() <https://docs.python.org/3/library/functions.html#eval>`_ function. As a fall-back
+method, this checker also tries to load dependencies from the ``requirements.txt`` file.
 
 At this point it is very important to be aware of the consequences of the above approach. One
 might inject malicious code into the ``setup.py`` file, which will be executed by this checker.

src/flake8_requirements/checker.py

@@ -13,7 +13,7 @@
 from .modules import STDLIB_PY3
 
 # NOTE: Changing this number will alter package version as well.
-__version__ = "1.0.0"
+__version__ = "1.1.0"
 __license__ = "MIT"
 
 LOG = getLogger('flake8.plugin.requires')
@@ -256,6 +256,7 @@ def __init__(self, tree, filename, lines=None):
         self.tree = tree
         self.filename = filename
         self.lines = lines
+        self.requirements = self.get_requirements()
         self.setup = self.get_setup()
 
     @classmethod
@@ -284,6 +285,17 @@ def parse_options(cls, options):
             ]
         }
 
+    @classmethod
+    @memoize
+    def get_requirements(cls):
+        """Get package requirements."""
+        try:
+            with open("requirements.txt") as f:
+                return tuple(parse_requirements(f.readlines()))
+        except IOError as e:
+            LOG.debug("Couldn't open requirements file: %s", e)
+            return ()
+
     @classmethod
     @memoize
     def get_setup(cls):
@@ -325,10 +337,13 @@ def modcmp(lib=(), test=()):
             modules = self.known_modules[modules[0]]
         mods_1st_party.update(split(x) for x in modules)
 
-        requirements = self.setup.get_requirements(
-            setup=self.processing_setup_py,
-            tests=True,
-        )
+        requirements = self.requirements
+        if self.setup.redirected:
+            # Use requirements from setup if available.
+            requirements = self.setup.get_requirements(
+                setup=self.processing_setup_py,
+                tests=True,
+            )
 
         # Get 3rd party module names based on requirements.
         for requirement in requirements:

test/test_checker.py

@@ -7,6 +7,7 @@
 class SetupVisitorMock(checker.SetupVisitor):
 
     def __init__(self):
+        self.redirected = True
         self.keywords = {
             'name': "flake8-requires",
             'install_requires': [