Use setup requirements when checking setup.py

src/flake8_requirements/checker.py

@@ -3,6 +3,8 @@
 import sys
 from collections import namedtuple
 from itertools import chain
+from logging import getLogger
+from os import path
 
 from pkg_resources import parse_requirements
 
@@ -14,6 +16,8 @@
 __version__ = "1.0.0"
 __license__ = "MIT"
 
+LOG = getLogger('flake8.plugin.requires')
+
 ERRORS = {
     'I900': "I900 '{pkg}' not listed as a requirement",
     'I901': "I901 '{pkg}' required but not used",
@@ -147,7 +151,7 @@ def setup(**kw):
             {'__file__': "setup.py", '__f8r_setup': setup},
         )
 
-    def get_requirements(self, install=True, extras=True):
+    def get_requirements(self, install=True, extras=True, setup=False):
         """Get package requirements."""
         requires = []
         if install:
@@ -157,6 +161,10 @@ def get_requirements(self, install=True, extras=True):
         if extras:
             for r in self.keywords.get('extras_require', {}).values():
                 requires.extend(parse_requirements(r))
+        if setup:
+            requires.extend(parse_requirements(
+                self.keywords.get('setup_requires', ()),
+            ))
         return requires
 
     def visit_Call(self, node):
@@ -202,8 +210,9 @@ class Flake8Checker(object):
 
     def __init__(self, tree, filename, lines=None):
         """Initialize requirements checker."""
-        self.setup = self.get_setup()
         self.tree = tree
+        self.filename = filename
+        self.setup = self.get_setup()
 
     @classmethod
     def add_options(cls, manager):
@@ -231,10 +240,25 @@ def parse_options(cls, options):
             ]
         }
 
-    def get_setup(self):
+    @classmethod
+    def get_setup(cls):
         """Get package setup."""
-        with open("setup.py") as f:
-            return SetupVisitor(ast.parse(f.read()))
+        if not getattr(cls, '_setup', None):
+            try:
+                with open("setup.py") as f:
+                    cls._setup = SetupVisitor(ast.parse(f.read()))
+            except IOError as e:
+                LOG.warning("Couldn't open setup file: %s", e)
+                cls._setup = SetupVisitor(ast.parse(""))
+        return cls._setup
+
+    @property
+    def processing_setup_py(self):
+        """Determine whether we are processing setup.py file."""
+        try:
+            return path.samefile(self.filename, "setup.py")
+        except OSError:
+            return False
 
     def run(self):
         """Run checker."""
@@ -258,15 +282,27 @@ 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,
+        )
+
         # Get 3rd party module names based on requirements.
-        for requirement in self.setup.get_requirements():
+        for requirement in requirements:
             modules = [project2module(requirement.project_name)]
             if modules[0] in KNOWN_3RD_PARTIES:
                 modules = KNOWN_3RD_PARTIES[modules[0]]
             if modules[0] in self.known_modules:
                 modules = self.known_modules[modules[0]]
             mods_3rd_party.update(split(x) for x in modules)
 
+        # When processing setup.py file, forcefully add setuptools to the
+        # project requirements. Setuptools might be required to build the
+        # project, even though it is not listed as a requirement - this
+        # package is required to run setup.py, so listing it as a setup
+        # requirement would be pointless.
+        if self.processing_setup_py:
+            mods_3rd_party.add(split("setuptools"))
+
         for node in ImportVisitor(self.tree).imports:
             _mod = split(node.mod)
             _alt = split(node.alt)

test/test_checker.py

@@ -1,34 +1,38 @@
 import ast
 import unittest
 
-from pkg_resources import parse_requirements
-
 from flake8_requirements import checker
 
 
-class SetupVisitorMock:
-    keywords = {
-        'name': "flake8-requires",
-    }
+class SetupVisitorMock(checker.SetupVisitor):
 
-    def get_requirements(self):
-        return parse_requirements((
-            "foo",
-            "bar",
-            "hyp-hen",
-            "python-boom",
-            "setuptools",
-            "space.module",
-        ))
+    def __init__(self):
+        self.keywords = {
+            'name': "flake8-requires",
+            'install_requires': [
+                "foo",
+                "bar",
+                "hyp-hen",
+                "python-boom",
+                "pillow",
+                "space.module",
+            ],
+        }
 
 
 class Flake8Checker(checker.Flake8Checker):
-    def get_setup(self):
+
+    @classmethod
+    def get_setup(cls):
         return SetupVisitorMock()
 
+    @property
+    def processing_setup_py(self):
+        return self.filename == "setup.py"
+
 
-def check(code):
-    return list(Flake8Checker(ast.parse(code), "<unknown>").run())
+def check(code, filename="<unknown>"):
+    return list(Flake8Checker(ast.parse(code), filename).run())
 
 
 class Flake8CheckerTestCase(unittest.TestCase):
@@ -71,8 +75,8 @@ def test_3rd_party_hyphen(self):
         errors = check("from hyp_hen import Hyphen")
         self.assertEqual(len(errors), 0)
 
-    def test_3rd_party_multi_module(self):
-        errors = check("import pkg_resources")
+    def test_3rd_party_known_module(self):
+        errors = check("import PIL")
         self.assertEqual(len(errors), 0)
 
     def test_non_top_level_import(self):
@@ -96,3 +100,13 @@ def test_relative(self):
         self.assertEqual(len(errors), 0)
         errors = check("from ..local import local")
         self.assertEqual(len(errors), 0)
+
+    def test_setup_py(self):
+        errors = check("from setuptools import setup", "setup.py")
+        self.assertEqual(len(errors), 0)
+        errors = check("from setuptools import setup", "xxx.py")
+        self.assertEqual(len(errors), 1)
+        self.assertEqual(
+            errors[0][2],
+            "I900 'setuptools' not listed as a requirement",
+        )