Add no_site_packages setting

mypy/build.py

@@ -2521,14 +2521,29 @@ def log_configuration(manager: BuildManager) -> None:
     """Output useful configuration information to LOG and TRACE"""
 
     manager.log()
-    configuration_vars = (
+    configuration_vars = [
         ("Mypy Version", __version__),
         ("Config File", (manager.options.config_file or "Default")),
-        ("Configured Executable", manager.options.python_executable),
+    ]
+
+    src_pth_str = "Source Path"
+    src_pths = list(manager.source_set.source_paths.copy())
+    src_pths.sort()
+
+    if len(src_pths) > 1:
+        src_pth_str += "s"
+        configuration_vars.append((src_pth_str, " ".join(src_pths)))
+    elif len(src_pths) == 1:
+        configuration_vars.append((src_pth_str, src_pths.pop()))
+    else:
+        configuration_vars.append((src_pth_str, "None"))
+
+    configuration_vars.extend([
+        ("Configured Executable", manager.options.python_executable or "None"),
         ("Current Executable", sys.executable),
         ("Cache Dir", manager.options.cache_dir),
         ("Compiled", str(not __file__.endswith(".py"))),
-    )
+    ])
 
     for conf_name, conf_value in configuration_vars:
         manager.log("{:24}{}".format(conf_name + ":", conf_value))

mypy/config_parser.py

@@ -79,6 +79,7 @@ def split_and_match_files(paths: str) -> List[str]:
     # These two are for backwards compatibility
     'silent_imports': bool,
     'almost_silent': bool,
+    'no_site_packages': bool,
     'plugins': lambda s: [p.strip() for p in s.split(',')],
     'always_true': lambda s: [p.strip() for p in s.split(',')],
     'always_false': lambda s: [p.strip() for p in s.split(',')],

mypy/main.py

@@ -218,7 +218,7 @@ def infer_python_executable(options: Options,
     python_executable = special_opts.python_executable or options.python_executable
 
     if python_executable is None:
-        if not special_opts.no_executable:
+        if not special_opts.no_executable and not options.no_site_packages:
             python_executable = _python_executable_from_version(options.python_version)
     options.python_executable = python_executable
 
@@ -839,7 +839,7 @@ def set_strict_flags() -> None:
     except PythonExecutableInferenceError as e:
         parser.error(str(e))
 
-    if special_opts.no_executable:
+    if special_opts.no_executable or options.no_site_packages:
         options.python_executable = None
 
     # Paths listed in the config file will be ignored if any paths are passed on

mypy/options.py

@@ -77,6 +77,7 @@ def __init__(self) -> None:
         self.report_dirs = {}  # type: Dict[str, str]
         # Show errors in PEP 561 packages/site-packages modules
         self.no_silence_site_packages = False
+        self.no_site_packages = False
         self.ignore_missing_imports = False
         self.follow_imports = 'normal'  # normal|silent|skip|error
         # Whether to respect the follow_imports setting even for stub files.

mypy/test/testpep561.py

@@ -1,6 +1,7 @@
 from contextlib import contextmanager
 import os
 import pytest  # type: ignore
+import re
 import subprocess
 from subprocess import PIPE
 import sys
@@ -72,7 +73,7 @@ def install_package(pkg: str,
     working_dir = os.path.join(package_path, pkg)
     with tempfile.TemporaryDirectory() as dir:
         if use_pip:
-            install_cmd = [python_executable, '-m', 'pip', 'install', '-b {}'.format(dir)]
+            install_cmd = [python_executable, '-m', 'pip', 'install', '-b', '{}'.format(dir)]
             if editable:
                 install_cmd.append('-e')
             install_cmd.append('.')
@@ -100,10 +101,11 @@ def test_pep561(testcase: DataDrivenTestCase) -> None:
     else:
         python = sys.executable
     assert python is not None, "Should be impossible"
-    pkgs, args = parse_pkgs(testcase.input[0])
+    pkgs, pip_args = parse_pkgs(testcase.input[0])
+    mypy_args = parse_mypy_args(testcase.input[1])
     use_pip = True
     editable = False
-    for arg in args:
+    for arg in pip_args:
         if arg == 'no-pip':
             use_pip = False
         elif arg == 'editable':
@@ -122,9 +124,14 @@ def test_pep561(testcase: DataDrivenTestCase) -> None:
             with open(program, 'w', encoding='utf-8') as f:
                 for s in testcase.input:
                     f.write('{}\n'.format(s))
-            cmd_line = [program, '--no-incremental', '--no-error-summary']
+            cmd_line = mypy_args + [program, '--no-incremental', '--no-error-summary']
             if python_executable != sys.executable:
                 cmd_line.append('--python-executable={}'.format(python_executable))
+            if testcase.files != []:
+                for name, content in testcase.files:
+                    if 'mypy.ini' in name:
+                        with open('mypy.ini', 'w') as m:
+                            m.write(content)
             output = []
             # Type check the module
             out, err, returncode = mypy.api.run(cmd_line)
@@ -153,6 +160,13 @@ def parse_pkgs(comment: str) -> Tuple[List[str], List[str]]:
         return ([pkg.strip() for pkg in pkgs_str.split(',')], [arg.strip() for arg in args])
 
 
+def parse_mypy_args(line: str) -> List[str]:
+    m = re.match('# flags: (.*)$', line)
+    if not m:
+        return []  # No args; mypy will spit out an error.
+    return m.group(1).split()
+
+
 @pytest.mark.skipif(sys.platform == 'darwin' and hasattr(sys, 'base_prefix') and
                     sys.base_prefix != sys.prefix,
                     reason="Temporarily skip to avoid having a virtualenv within a venv.")

test-data/unit/pep561.test

@@ -1,3 +1,16 @@
+[case testTypedPkgNoSitePkgsIgnoredImports]
+# pkgs: typedpkg
+# flags: --no-site-packages
+from typedpkg.sample import ex
+from typedpkg import dne
+a = ex([''])
+reveal_type(a)
+[file mypy.ini]
+\[mypy]
+ignore_missing_imports = True
+[out]
+testTypedPkgNoSitePkgsIgnoredImports.py:6: note: Revealed type is 'Any'
+
 [case testTypedPkgSimple]
 # pkgs: typedpkg
 from typedpkg.sample import ex
@@ -7,6 +20,34 @@ reveal_type(a)
 [out]
 testTypedPkgSimple.py:5: note: Revealed type is 'builtins.tuple[builtins.str]'
 
+[case testTypedPkg_config_nositepackages]
+# pkgs: typedpkg
+from typedpkg.sample import ex
+from typedpkg import dne
+a = ex([''])
+reveal_type(a)
+[file mypy.ini]
+\[mypy]
+no_site_packages=True
+[out]
+testTypedPkg_config_nositepackages.py:2: error: Cannot find implementation or library stub for module named 'typedpkg.sample'
+testTypedPkg_config_nositepackages.py:2: note: See https://mypy.readthedocs.io/en/latest/running_mypy.html#missing-imports
+testTypedPkg_config_nositepackages.py:3: error: Cannot find implementation or library stub for module named 'typedpkg'
+testTypedPkg_config_nositepackages.py:5: note: Revealed type is 'Any'
+
+[case testTypedPkg_args_nositepackages]
+# pkgs: typedpkg
+# flags: --no-site-packages
+from typedpkg.sample import ex
+from typedpkg import dne
+a = ex([''])
+reveal_type(a)
+[out]
+testTypedPkg_args_nositepackages.py:3: error: Cannot find implementation or library stub for module named 'typedpkg.sample'
+testTypedPkg_args_nositepackages.py:3: note: See https://mypy.readthedocs.io/en/latest/running_mypy.html#missing-imports
+testTypedPkg_args_nositepackages.py:4: error: Cannot find implementation or library stub for module named 'typedpkg'
+testTypedPkg_args_nositepackages.py:6: note: Revealed type is 'Any'
+
 [case testTypedPkgStubs]
 # pkgs: typedpkg-stubs
 from typedpkg.sample import ex