Merge branch 'master' into import-cycle

* master: (27 commits)
  Don't call --strict-optional and --incremental experimental (python#4642)
  Sync typeshed (python#4641)
  Fix callable types with inconsistent argument counts (python#4611)
  Fix example (add 'class A:')
  Make psutil an optional dependency (python#4634)
  mypy and mypy_extensions aren't posix only (python#3765)
  Documentation for attr support (python#4632)
  Use read_with_python_encoding in stubgen to handle file encoding (python#3790)
  Sync typeshed (python#4631)
  Add remaining core team emails to CREDITS (python#4629)
  Fix issues with attr code. (python#4628)
  Better support for converter in attrs plugin. (python#4607)
  Clean up credits (python#4626)
  Support type aliases in fine-grained incremental mode (python#4525)
  Fine-grained: Fix crash caused by unreachable class (python#4613)
  Treat divmod like a binary operator (python#4585)
  Sync typeshed (python#4605)
  Fine-grained: Don't infer partial types from multiple targets (python#4553)
  Fine-grained: Compare symbol table snapshots when following dependencies (python#4598)
  Fix type of forward reference to a decorated class method (python#4486)
  ...

Author: carljm

CONTRIBUTING.md

@@ -80,11 +80,7 @@ For every pull request, we aim to promptly either merge it or say why
 it's not yet ready; if you go a few days without a reply, please feel
 free to ping the thread by adding a new comment.
 
-At present the core developers are (alphabetically):
-* David Fisher (@ddfisher)
-* Jukka Lehtosalo (@JukkaL)
-* Greg Price (@gnprice)
-* Guido van Rossum (@gvanrossum)
+For a list of mypy core developers, see the file [CREDITS](CREDITS).
 
 
 Preparing Changes

CREDITS

@@ -7,12 +7,17 @@ https://github.com/python/mypy/commits/master
 For lists of contributors per mypy release (including typeshed) see
 the release blog posts at https://mypy-lang.blogspot.com/.
 
-Mypy team:
+Dropbox core team:
 
   Jukka Lehtosalo <[email protected]>
   Guido van Rossum <[email protected]>
-  Ivan Levkivskyi
-  Michael J. Sullivan
+  Ivan Levkivskyi <[email protected]>
+  Michael J. Sullivan <[email protected]>
+
+Non-Dropbox core team members:
+
+  Ethan Smith
+  Jelle Zijlstra
 
 Past Dropbox core team members:
 
@@ -23,11 +28,6 @@ Past Dropbox core team members:
   Michael Lee
   Reid Barton
 
-Non-Dropbox core team members:
-
-  Ethan Smith
-  Jelle Zijlstra
-
 Additional thanks to:
 
   Alex Allain

docs/source/additional_features.rst

@@ -7,3 +7,79 @@ including the following:
 - inheritance between generic classes
 - compatibility and subtyping of generic types, including covariance of generic types
 - ``super()``
+
+
+.. _attrs_package:
+
+The attrs package
+*****************
+
+`attrs <https://www.attrs.org/en/stable>`_ is a package that lets you define
+classes without writing boilerplate code. Mypy can detect uses of the
+package and will generate the necessary method definitions for decorated
+classes using the type annotations it finds.
+Type annotations can be added as follows:
+
+.. code-block:: python
+
+    import attr
+    @attr.s
+    class A:
+        one: int = attr.ib()          # Variable annotation (Python 3.6+)
+        two = attr.ib()  # type: int  # Type comment
+        three = attr.ib(type=int)     # type= argument
+
+If you're using ``auto_attribs=True`` you must use variable annotations.
+
+.. code-block:: python
+
+    import attr
+    @attr.s(auto_attribs=True)
+    class A:
+        one: int
+        two: int = 7
+        three: int = attr.ib(8)
+
+Typeshed has a couple of "white lie" annotations to make type checking
+easier. ``attr.ib`` and ``attr.Factory`` actually return objects, but the
+annotation says these return the types that they expect to be assigned to.
+That enables this to work:
+
+.. code-block:: python
+
+    import attr
+    from typing import Dict
+    @attr.s(auto_attribs=True)
+    class A:
+        one: int = attr.ib(8)
+        two: Dict[str, str] = attr.Factory(dict)
+        bad: str = attr.ib(16)   # Error: can't assign int to str
+
+Caveats/Known Issues
+====================
+
+* The detection of attr classes and attributes works by function name only.
+  This means that if you have your own helper functions that, for example,
+  ``return attr.ib()`` mypy will not see them.
+
+* All boolean arguments that mypy cares about must be literal ``True`` or ``False``.
+  e.g the following will not work:
+
+  .. code-block:: python
+
+      import attr
+      YES = True
+      @attr.s(init=YES)
+      class A:
+          ...
+
+* Currently, ``converter`` only supports named functions.  If mypy finds something else it
+  will complain about not understanding the argument and the type annotation in
+  ``__init__`` will be replaced by ``Any``.
+
+* `Validator decorators <http://www.attrs.org/en/stable/examples.html#decorator>`_
+  and `default decorators <http://www.attrs.org/en/stable/examples.html#defaults>`_
+  are not type-checked against the attribute they are setting/validating.
+
+* Method definitions added by mypy currently overwrite any existing method
+  definitions.

docs/source/command_line.rst

@@ -292,22 +292,11 @@ Here are some more useful flags:
 - ``--ignore-missing-imports`` suppresses error messages about imports
   that cannot be resolved (see :ref:`follow-imports` for some examples).
 
-- ``--strict-optional`` enables experimental strict checking of ``Optional[...]``
-  types and ``None`` values. Without this option, mypy doesn't generally check the
-  use of ``None`` values -- they are valid everywhere. See :ref:`strict_optional` for
-  more about this feature.
-
-- ``--strict-optional-whitelist`` attempts to suppress strict Optional-related
-  errors in non-whitelisted files.  Takes an arbitrary number of globs as the
-  whitelist.  This option is intended to be used to incrementally roll out
-  ``--strict-optional`` to a large codebase that already has mypy annotations.
-  However, this flag comes with some significant caveats.  It does not suppress
-  all errors caused by turning on ``--strict-optional``, only most of them, so
-  there may still be a bit of upfront work to be done before it can be used in
-  CI.  It will also suppress some errors that would be caught in a
-  non-strict-Optional run.  Therefore, when using this flag, you should also
-  re-check your code without ``--strict-optional`` to ensure new type errors
-  are not introduced.
+- ``--strict-optional`` enables strict checking of ``Optional[...]``
+  types and ``None`` values. Without this option, mypy doesn't
+  generally check the use of ``None`` values -- they are valid
+  everywhere. See :ref:`strict_optional` for more about this feature.
+  This flag will become the default in the near future.
 
 - ``--disallow-untyped-defs`` reports an error whenever it encounters
   a function definition without type annotations.
@@ -342,17 +331,19 @@ Here are some more useful flags:
 
 .. _incremental:
 
-- ``--incremental`` is an experimental option that enables a module
-  cache. When enabled, mypy caches results from previous runs
-  to speed up type checking. Incremental mode can help when most parts
-  of your program haven't changed since the previous mypy run.  A
-  companion flag is ``--cache-dir DIR``, which specifies where the
-  cache files are written.  By default this is ``.mypy_cache`` in the
-  current directory.  While the cache is only read in incremental
-  mode, it is written even in non-incremental mode, in order to "warm"
-  the cache.  To disable writing the cache, use
-  ``--cache-dir=/dev/null`` (UNIX) or ``--cache-dir=nul`` (Windows).
-  Cache files belonging to a different mypy version are ignored.
+- ``--incremental`` enables a module cache, using results from
+  previous runs to speed up type checking. Incremental mode can help
+  when most parts of your program haven't changed since the previous
+  mypy run.
+
+- ``--cache-dir DIR`` is a companion flag to ``-incremental``, which
+  specifies where the cache files are written.  By default this is
+  ``.mypy_cache`` in the current directory.  While the cache is only
+  read in incremental mode, it is written even in non-incremental
+  mode, in order to "warm" the cache.  To disable writing the cache,
+  use ``--cache-dir=/dev/null`` (UNIX) or ``--cache-dir=nul``
+  (Windows).  Cache files belonging to a different mypy version are
+  ignored.
 
 .. _quick-mode:
 

docs/source/kinds_of_types.rst

@@ -432,13 +432,14 @@ idiomatic.
 
 .. _strict_optional:
 
-Experimental strict optional type and None checking
+Strict optional type and None checking
 ***************************************************
 
 Currently, ``None`` is a valid value for each type, similar to
 ``null`` or ``NULL`` in many languages. However, you can use the
-experimental ``--strict-optional`` command line option to tell mypy
-that types should not include ``None``
+``--strict-optional`` command line option
+(which will become the default in the near future)
+to tell mypy that types should not include ``None``
 by default. The ``Optional`` type modifier is then used to define
 a type variant that includes ``None``, such as ``Optional[int]``:
 
@@ -478,10 +479,6 @@ recognizes ``is None`` checks:
 Mypy will infer the type of ``x`` to be ``int`` in the else block due to the
 check against ``None`` in the if condition.
 
-.. note::
-
-    ``--strict-optional`` is experimental and still has known issues.
-
 .. _noreturn:
 
 The NoReturn type
@@ -986,7 +983,7 @@ annotated the first example as the following:
    def squares(n: int) -> Generator[int, None, None]:
        for i in range(n):
            yield i * i
-           
+
 This is slightly different from using ``Iterable[int]`` or ``Iterator[int]``,
 since generators have ``close()``, ``send()``, and ``throw()`` methods that
 generic iterables don't. If you will call these methods on the returned

extensions/setup.py

@@ -17,7 +17,6 @@
     'Environment :: Console',
     'Intended Audience :: Developers',
     'License :: OSI Approved :: MIT License',
-    'Operating System :: POSIX',
     'Programming Language :: Python :: 2',
     'Programming Language :: Python :: 2.7',
     'Programming Language :: Python :: 3',
@@ -37,7 +36,6 @@
     author_email='[email protected]',
     url='http://www.mypy-lang.org/',
     license='MIT License',
-    platforms=['POSIX'],
     py_modules=['mypy_extensions'],
     classifiers=classifiers,
     install_requires=[