Allow user to specify custom typeshed directory

Author: ddfisher

mypy/build.py

@@ -125,12 +125,20 @@ def build(sources: List[BuildSource],
         directories; if omitted, use '.' as the data directory
     """
 
-    data_dir = default_data_dir(bin_dir)
+    custom_typeshed_name = None
+    if options.custom_typeshed_dir:
+        custom_data_dir, custom_typeshed_name = os.path.split(
+            options.custom_typeshed_dir.rstrip(os.sep))
+        data_dir = custom_data_dir
+    else:
+        data_dir = default_data_dir(bin_dir)
 
     find_module_clear_caches()
 
     # Determine the default module search path.
-    lib_path = default_lib_path(data_dir, options.python_version)
+    lib_path = default_lib_path(data_dir,
+                                options.python_version,
+                                custom_typeshed_name=custom_typeshed_name)
 
     if options.use_builtins_fixtures:
         # Use stub builtins (to speed up test cases and to make them easier to
@@ -244,10 +252,13 @@ def mypy_path() -> List[str]:
     return path_env.split(os.pathsep)
 
 
-def default_lib_path(data_dir: str, pyversion: Tuple[int, int]) -> List[str]:
+def default_lib_path(data_dir: str,
+                     pyversion: Tuple[int, int],
+                     custom_typeshed_name: str = None) -> List[str]:
     """Return default standard library search paths."""
     # IDEA: Make this more portable.
     path = []  # type: List[str]
+    typeshed_name = custom_typeshed_name or 'typeshed'
 
     auto = os.path.join(data_dir, 'stubs-auto')
     if os.path.isdir(auto):
@@ -261,7 +272,7 @@ def default_lib_path(data_dir: str, pyversion: Tuple[int, int]) -> List[str]:
     # (Note that 3.1 and 3.0 aren't really supported, but we don't care.)
     for v in versions + [str(pyversion[0]), '2and3']:
         for lib_type in ['stdlib', 'third_party']:
-            stubdir = os.path.join(data_dir, 'typeshed', lib_type, v)
+            stubdir = os.path.join(data_dir, typeshed_name, lib_type, v)
             if os.path.isdir(stubdir):
                 path.append(stubdir)
 

mypy/main.py

@@ -180,6 +180,8 @@ def parse_version(v: str) -> Tuple[int, int]:
                         help="dump type inference stats")
     parser.add_argument('--custom-typing', metavar='MODULE', dest='custom_typing_module',
                         help="use a custom typing module")
+    parser.add_argument('--custom-typeshed-dir', metavar='DIR',
+                        help="use the custom typeshed in DIR")
 
     report_group = parser.add_argument_group(
         title='report generation',

mypy/options.py

@@ -16,7 +16,8 @@ def __init__(self) -> None:
         # -- build options --
         self.build_type = BuildType.STANDARD
         self.python_version = defaults.PYTHON3_VERSION
-        self.custom_typing_module = None  # type: str
+        self.custom_typing_module = None  # type: Optional[str]
+        self.custom_typeshed_dir = None  # type: Optional[str]
         self.report_dirs = {}  # type: Dict[str, str]
         self.silent_imports = False
         self.almost_silent = False