Handle PIP requirements text file options

Reference:
https://pip.pypa.io/en/stable/reference/pip_install/#requirements-file-format

Fixes arkq#9 and closes arkq#11

src/flake8_requirements/checker.py

@@ -68,6 +68,19 @@ def project2module(project):
     return project
 
 
+def joinlines(lines):
+    """Strip comments and join line continuations."""
+    joined_line = ""
+    for line in map(lambda x: x.strip(), lines):
+        if not line or line.startswith("#"):
+            continue
+        if line.endswith("\\"):
+            joined_line += line[:-1]
+            continue
+        yield joined_line + line
+        joined_line = ""
+
+
 class ImportVisitor(ast.NodeVisitor):
     """Import statement visitor."""
 
@@ -318,25 +331,32 @@ def parse_options(cls, options):
     @classmethod
     def resolve_requirement(cls, requirement, max_depth=0):
         """Resolves flags like -r in an individual requirement line."""
-        requirement = requirement.strip()
 
-        if requirement.startswith("#") or not requirement:
-            return []
+        option = None
+        option_matcher = re.match(r"(-[\w-]+)(.*)", requirement)
+        if option_matcher:
+            option = option_matcher.group(1)
+            requirement = option_matcher.group(2).lstrip()
 
-        if requirement.startswith("-r "):
+        if option in ("-e", "--editable"):
+            # We do not care about installation mode.
+            option = None
+
+        if option in ("-r", "--requirement"):
             # Error out if we need to recurse deeper than allowed.
             if max_depth <= 0:
                 msg = "Cannot resolve {}: beyond max depth"
-                raise RuntimeError(msg.format(requirement.strip()))
-
+                raise RuntimeError(msg.format(requirement))
             resolved = []
             # Error out if requirements file cannot be opened.
-            with open(requirement[3:].lstrip()) as f:
-                for line in f.readlines():
+            with open(requirement) as f:
+                for line in joinlines(f.readlines()):
                     resolved.extend(cls.resolve_requirement(
                         line, max_depth - 1))
             return resolved
 
+        if option:
+            return []
         return [requirement]
 
     @classmethod

test/test_requirements.py

@@ -18,19 +18,16 @@ class RequirementsTestCase(unittest.TestCase):
     def setUp(self):
         memoize.mem = {}
 
-    def test_resolve_requirement_with_blank(self):
-        self.assertEqual(Flake8Checker.resolve_requirement(""), [])
-
-    def test_resolve_requirement_with_comment(self):
+    def test_resolve_requirement(self):
         self.assertEqual(
-            Flake8Checker.resolve_requirement("#-r requirements.txt"),
-            [],
+            Flake8Checker.resolve_requirement("foo >= 1.0.0"),
+            ["foo >= 1.0.0"],
         )
 
-    def test_resolve_requirement_with_simple(self):
+    def test_resolve_requirement_option(self):
         self.assertEqual(
-            Flake8Checker.resolve_requirement("foo >= 1.0.0"),
-            ["foo >= 1.0.0"],
+            Flake8Checker.resolve_requirement("--extra-index-url"),
+            [],
         )
 
     def test_resolve_requirement_with_file_beyond_max_depth(self):
@@ -53,14 +50,22 @@ def test_resolve_requirement_with_file_content(self):
                 ["foo >= 1.0.0", "bar <= 1.0.0"],
             )
 
+    def test_resolve_requirement_with_file_content_line_continuation(self):
+        content = "foo[bar] \\\n>= 1.0.0\n"
+        with mock.patch(builtins_open, mock.mock_open(read_data=content)):
+            self.assertEqual(
+                Flake8Checker.resolve_requirement("-r requirements.txt", 1),
+                ["foo[bar] >= 1.0.0"],
+            )
+
     def test_resolve_requirement_with_file_recursion_beyond_max_depth(self):
         content = "-r requirements.txt\n"
         with mock.patch(builtins_open, mock.mock_open(read_data=content)):
             with self.assertRaises(RuntimeError):
                 Flake8Checker.resolve_requirement("-r requirements.txt", 1),
 
     def test_resolve_requirement_with_file_recursion(self):
-        content = "foo >= 1.0.0\n-r inner.txt\nbar <= 1.0.0\n"
+        content = "--requirement inner.txt\nbar <= 1.0.0\n"
         inner_content = "# inner\nbaz\n\nqux\n"
 
         with mock.patch(builtins_open, mock.mock_open()) as m:
@@ -71,7 +76,7 @@ def test_resolve_requirement_with_file_recursion(self):
 
             self.assertEqual(
                 Flake8Checker.resolve_requirement("-r requirements.txt", 2),
-                ["foo >= 1.0.0", "baz", "qux", "bar <= 1.0.0"],
+                ["baz", "qux", "bar <= 1.0.0"],
             )
 
     def test_init_with_no_requirements(self):