Merge pull request #323 from Carreau/mypy

Introduce mypy to catch typing error ahead of time

.github/workflows/lint.yml

@@ -19,8 +19,12 @@ jobs:
     - name: Install and update Python dependencies on Python 3
       run: |
         python -m pip install --upgrade pip setuptools wheel
-        python -m pip install --upgrade pyflakes flake8 
+        python -m pip install --upgrade pyflakes flake8 mypy
+        python -m pip install types-six
         pip install -e .
+    - name: Mypy
+      run: |
+        mypy lib/python --ignore-missing-imports
     - name: lint
       run: |
         flake8 --exclude known_imports,etc,__init__.py --select=F;

lib/python/pyflyby/__init__.py

@@ -40,6 +40,8 @@
                                         enable_signal_handler_breakpoint,
                                         waitpoint)
 
+from   typing                   import Sequence
+
 
 # Promote the function & classes that we've chosen to expose publicly to be
 # known as pyflyby.Foo instead of pyflyby._module.Foo.
@@ -51,4 +53,4 @@
 
 # Discourage "from pyflyby import *".
 # Use the tidy-imports/autoimporter instead!
-__all__ = []
+__all__:Sequence[str] = []

lib/python/pyflyby/_autoimp.py

@@ -24,6 +24,8 @@
 from   pyflyby._modules         import ModuleHandle
 from   pyflyby._parse           import PythonBlock, infer_compile_mode, _is_ast_str
 
+from   typing                   import Set, Any
+
 if sys.version_info >= (3, 12):
     ATTRIBUTE_NAME = "value"
 else:
@@ -39,8 +41,12 @@
 else:
     LOAD_SHIFT = 0
 
-NoneType = type(None)
-EllipsisType = type(Ellipsis)
+if sys.version_info >= (3,10):
+    from types import NoneType, EllipsisType
+else:
+    NoneType = type(None)
+    EllipsisType = type(Ellipsis)
+
 
 class _ClassScope(dict):
     pass
@@ -1605,7 +1611,7 @@ def get_known_import(fullname, db=None):
     return None
 
 
-_IMPORT_FAILED = set()
+_IMPORT_FAILED:Set[Any] = set()
 """
 Set of imports we've already attempted and failed.
 """

lib/python/pyflyby/_cmdline.py

@@ -415,8 +415,8 @@ def on_error_filename_arg(arg):
             continue
     if errors:
         msg = "\n%s: encountered the following problems:\n" % (sys.argv[0],)
-        for e in errors:
-            lines = e.splitlines()
+        for er in errors:
+            lines = er.splitlines()
             msg += "    " + lines[0] + '\n'.join(
                 ("            %s"%line for line in lines[1:]))
         raise SystemExit(msg)

lib/python/pyflyby/_comms.py

@@ -9,6 +9,8 @@
 from   pyflyby._importstmt      import Import
 from   pyflyby._log             import logger
 
+from   typing                   import Dict, Any
+
 # These are comm targets that the frontend (lab/notebook) is expected to
 # open. At this point, we handle only missing imports and
 # formatting imports
@@ -23,7 +25,7 @@
 pyflyby_comm_targets= [MISSING_IMPORTS, FORMATTING_IMPORTS, TIDY_IMPORTS]
 
 # A map of the comms opened with a given target name.
-comms = {}
+comms:Dict[str, Any] = {}
 
 # TODO: Document the expected contract for the different
 # custom comm messages

lib/python/pyflyby/_file.py

@@ -1,15 +1,14 @@
 # pyflyby/_file.py.
 # Copyright (C) 2011, 2012, 2013, 2014, 2015, 2018 Karl Chen.
 # License: MIT http://opensource.org/licenses/MIT
-
-
+from __future__ import annotations
 
 from   functools                import total_ordering, cached_property
 import io
 import os
 import re
 import sys
-from   typing                   import Optional, Tuple
+from   typing                   import Optional, Tuple, ClassVar
 
 from   pyflyby._util            import cmp, memoize
 
@@ -30,6 +29,7 @@ class Filename(object):
 
     """
     _filename: str
+    STDIN: Filename
 
     def __new__(cls, arg):
         if isinstance(arg, cls):
@@ -236,6 +236,8 @@ class FilePos(object):
     lineno: int
     colno: int
 
+    _ONE_ONE: ClassVar[FilePos]
+
     def __new__(cls, *args):
         if len(args) == 0:
             return cls._ONE_ONE

lib/python/pyflyby/_flags.py

@@ -157,7 +157,7 @@ def from_ast(cls, nodes):
         return cls(flags)
 
     @cached_attribute
-    def names(self) -> Tuple[str]:
+    def names(self) -> Tuple[str, ...]:
         return tuple(
             n
             for f, n in _FLAGNAME_ITEMS

lib/python/pyflyby/_importclns.py

@@ -2,6 +2,8 @@
 # Copyright (C) 2011, 2012, 2013, 2014 Karl Chen.
 # License: MIT http://opensource.org/licenses/MIT
 
+from __future__ import annotations
+
 
 
 from   collections              import defaultdict
@@ -16,7 +18,7 @@
 from   pyflyby._util            import (cached_attribute, cmp, partition,
                                         stable_unique)
 
-from typing import Dict
+from typing import Dict, ClassVar
 
 
 class NoSuchImportError(ValueError):
@@ -46,6 +48,8 @@ class ImportSet(object):
     An ``ImportSet`` is an immutable data structure.
     """
 
+    _EMPTY : ClassVar[ImportSet]
+
     def __new__(cls, arg, ignore_nonimports=False, ignore_shadowed=False):
         """
         Return as an `ImportSet`.
@@ -519,6 +523,7 @@ class ImportMap(object):
     """
 
     _data: Dict
+    _EMPTY : ClassVar[ImportSet]
 
     def __new__(cls, arg):
         if isinstance(arg, cls):

lib/python/pyflyby/_importdb.py

@@ -8,14 +8,16 @@
 import os
 import re
 
-from pyflyby._file import Filename, expand_py_files_from_args, UnsafeFilenameError
+from   pyflyby._file            import Filename, expand_py_files_from_args, UnsafeFilenameError
 from   pyflyby._idents          import dotted_prefixes
 from   pyflyby._importclns      import ImportMap, ImportSet
 from   pyflyby._importstmt      import Import, ImportStatement
 from   pyflyby._log             import logger
 from   pyflyby._parse           import PythonBlock
 from   pyflyby._util            import cached_attribute, memoize, stable_unique
 
+from   typing                   import Dict, Any
+
 
 @memoize
 def _find_etc_dirs():
@@ -195,7 +197,7 @@ def __new__(cls, *args):
         return cls._from_args(arg) # PythonBlock, Filename, etc
 
 
-    _default_cache = {}
+    _default_cache: Dict[Any, Any] = {}
 
     @classmethod
     def clear_default_cache(cls):

lib/python/pyflyby/_interactive.py

@@ -1048,9 +1048,9 @@ def complete_symbol(fullname, namespaces, db=None, autoimported=None, ip=None,
             except LoadSymbolError as e2:
                 # Even after attempting auto-import, the symbol is still
                 # unavailable, or some other error occurred.  Nothing to complete.
-                e = getattr(e2, "__cause__", e2)
+                e3 = getattr(e2, "__cause__", e2)
                 logger.debug("complete_symbol(%r): couldn't load symbol %r: %s: %s",
-                             fullname, pname, type(e).__name__, e)
+                             fullname, pname, type(e3).__name__, e3)
                 return []
         logger.debug("complete_symbol(%r): %s == %r", fullname, pname, parent)
         results = set()

lib/python/pyflyby/_modules.py

@@ -13,6 +13,7 @@
 from   six                      import reraise
 import sys
 import types
+from typing                     import Dict, Any
 
 from   pyflyby._file            import FileText, Filename
 from   pyflyby._idents          import DottedIdentifier, is_identifier
@@ -22,6 +23,7 @@
                                         prefixes)
 
 
+
 class ErrorDuringImportError(ImportError):
     """
     Exception raised by import_module if the module exists but an exception
@@ -138,7 +140,7 @@ def __new__(cls, arg):
             return cls._from_module(arg)
         raise TypeError("ModuleHandle: unexpected %s" % (type(arg).__name__,))
 
-    _cls_cache = {}
+    _cls_cache:Dict[Any, Any] = {}
 
     @classmethod
     def _from_modulename(cls, modulename):

lib/python/pyflyby/_parse.py

@@ -13,7 +13,7 @@
 import sys
 from   textwrap                 import dedent
 import types
-from   typing                   import Optional
+from   typing                   import Optional, Union
 import warnings
 
 from   pyflyby._file            import FilePos, FileText, Filename
@@ -760,12 +760,15 @@ class PythonStatement:
     block: PythonBlock
 
     def __new__(cls, arg:PythonStatement, filename=None, startpos=None, flags=None):
+        arg_ : Union[PythonBlock, FileText, str, PythonStatement]
         if isinstance(arg, cls):
             if filename is startpos is flags is None:
                 return arg
-            arg = arg.block
+            arg_ = arg.block
             # Fall through
-        if isinstance(arg, (PythonBlock, FileText, str)):
+        else:
+            arg_ = arg
+        if isinstance(arg_, (PythonBlock, FileText, str)):
             block = PythonBlock(arg, filename=filename,
                                 startpos=startpos, flags=flags)
             statements = block.statements
@@ -776,7 +779,7 @@ def __new__(cls, arg:PythonStatement, filename=None, startpos=None, flags=None):
             statement, = statements
             assert isinstance(statement, cls)
             return statement
-        raise TypeError("PythonStatement: unexpected %s" % (type(arg).__name__,))
+        raise TypeError("PythonStatement: unexpected %s" % type(arg_).__name__)
 
     @classmethod
     def _construct_from_block(cls, block:PythonBlock):
@@ -796,7 +799,7 @@ def text(self) -> FileText:
         return self.block.text
 
     @property
-    def filename(self) -> Optional[str]:
+    def filename(self) -> Optional[Filename]:
         """
         :rtype:
           `Filename`

lib/python/pyflyby/autoimport.py

@@ -17,4 +17,4 @@
 
 install_auto_importer = enable_auto_importer
 
-__all__ = [install_auto_importer]
+__all__ = ['install_auto_importer']

mypy.ini

@@ -0,0 +1,14 @@
+[mypy]
+warn_incomplete_stub = False
+warn_unused_configs = True
+
+exclude = (?x)(
+    _dbg\.py
+    |_py\.py
+  )
+
+[mypy-epydoc]
+ignore_missing_imports = True
+
+[mypy-IPython]
+ignore_missing_imports = True