Merge pull request #187 from Nurdok/dunder_all_import_bugfix

Proper parsing of imports to avoid misunderstanding __all__ imports

Author: Nurdok

docs/release_notes.rst

@@ -13,14 +13,17 @@ New Features
   the summary of a multi-line docstring starts at the first line,
   respectively at the second line (#174).
 
-* Added D404 - First word of the docstring should not be `This`. It is turned
+* Added D404 - First word of the docstring should not be "This". It is turned
   off by default (#183).
 
 Bug Fixes
 
 * The error code D300 is now also being reported if a docstring has
   uppercase literals (``R`` or ``U``) as prefix (#176).
 
+* Fixed a bug where an ``__all__`` error was reported when ``__all__`` was
+  imported from another module with a different name (#182, #187).
+
 1.0.0 - January 30th, 2016
 --------------------------
 

src/pydocstyle.py

@@ -13,6 +13,7 @@
 import ast
 import copy
 import logging
+import textwrap
 import tokenize as tk
 from itertools import takewhile, dropwhile, chain
 from re import compile as re
@@ -486,20 +487,48 @@ def parse_definition(self, class_):
                   self.current.value)
         return definition
 
+    def check_current(self, kind=None, value=None):
+        msg = textwrap.dedent("""
+        Unexpected token at line {self.line}:
+
+        In file: {self.filename}
+
+        Got kind {self.current.kind!r}
+        Got value {self.current.value}
+        """.format(self=self))
+        kind_valid = self.current.kind == kind if kind else True
+        value_valid = self.current.value == value if value else True
+        assert kind_valid and value_valid, msg
+
     def parse_from_import_statement(self):
         """Parse a 'from x import y' statement.
 
         The purpose is to find __future__ statements.
 
         """
         log.debug('parsing from/import statement.')
+        is_future_import = self._parse_from_import_source()
+        self._parse_from_import_names(is_future_import)
+
+    def _parse_from_import_source(self):
+        """Parse the 'from x import' part in a 'from x import y' statement.
+
+        Return true iff `x` is __future__.
+        """
         assert self.current.value == 'from', self.current.value
         self.stream.move()
-        if self.current.value != '__future__':
-            return
+        is_future_import = self.current.value == '__future__'
         self.stream.move()
+        while (self.current.kind in (tk.DOT, tk.NAME, tk.OP) and
+               self.current.value != 'import'):
+            self.stream.move()
+        self.check_current(value='import')
         assert self.current.value == 'import', self.current.value
         self.stream.move()
+        return is_future_import
+
+    def _parse_from_import_names(self, is_future_import):
+        """Parse the 'y' part in a 'from x import y' statement."""
         if self.current.value == '(':
             self.consume(tk.OP)
             expected_end_kind = tk.OP
@@ -512,8 +541,9 @@ def parse_from_import_statement(self):
                 continue
             log.debug("parsing import, token is %r (%s)",
                       self.current.kind, self.current.value)
-            log.debug('found future import: %s', self.current.value)
-            self.future_imports[self.current.value] = True
+            if is_future_import:
+                log.debug('found future import: %s', self.current.value)
+                self.future_imports[self.current.value] = True
             self.consume(tk.NAME)
             log.debug("parsing import, token is %r (%s)",
                       self.current.kind, self.current.value)

src/tests/test_cases/all_import.py

@@ -0,0 +1,17 @@
+"""A valid module docstring."""
+
+from .all_import_aux import __all__
+from .expected import Expectation
+
+expectation = Expectation()
+expect = expectation.expect
+
+
+@expect("D103: Missing docstring in public function")
+def public_func():
+    pass
+
+
+@expect("D103: Missing docstring in public function")
+def this():
+    pass

src/tests/test_cases/all_import_as.py

@@ -0,0 +1,18 @@
+"""A valid module docstring."""
+
+from .all_import_aux import __all__ as not_dunder_all
+from .expected import Expectation
+
+expectation = Expectation()
+expect = expectation.expect
+
+__all__ = ('public_func', )
+
+
+@expect("D103: Missing docstring in public function")
+def public_func():
+    pass
+
+
+def private_func():
+    pass

src/tests/test_cases/all_import_aux.py

@@ -0,0 +1 @@
+__all__ = ('this', 'is', 'a', 'helper', 'file')

src/tests/test_definitions.py

@@ -260,6 +260,8 @@ def test_token_stream():
     'capitalization',
     'comment_after_def_bug',
     'multi_line_summary_start',
+    'all_import',
+    'all_import_as',
 ])
 def test_pep257(test_case):
     """Run domain-specific tests from test.py file."""