Allow apply to overwrite existing annotations using CLI flag. (#183)

It should be safe to remove the `args.existing_annotation_strategy = ExistingAnnotationStrategy.REPLICATE` line because that is now the default value in `args`.

This needed the latest ApplyTypeAnnotationsVisitor from libcst. Set the minimum libcst version to 0.3.5.

Note: I ran `pipenv update -d` to update the packages. This ended up upgrading pyflakes, which now errors on `List[make_forward_ref('Foo')]` saying "undefined name 'Foo'", probably because it's a literal non-class string within a container. So, I've temporarily silenced these errors in .flake8.

Fixed f-strings that didn't have expressions inside.

Co-authored-by: Pradeep Kumar Srinivasan <pradeepkumars@fb.com>

.flake8

@@ -1,2 +1,5 @@
 [flake8]
 max-line-length = 120
+per-file-ignores =
+    tests/test_stubs.py:F821
+    tests/test_typing.py:F821

monkeytype/cli.py

@@ -138,12 +138,18 @@ class HandlerError(Exception):
     pass
 
 
-def apply_stub_using_libcst(stub: str, source: str) -> str:
+def apply_stub_using_libcst(
+    stub: str, source: str, overwrite_existing_annotations: bool
+) -> str:
     try:
         stub_module = parse_module(stub)
         source_module = parse_module(source)
         context = CodemodContext()
-        ApplyTypeAnnotationsVisitor.add_stub_to_context(context, stub_module)
+        ApplyTypeAnnotationsVisitor.store_stub_in_context(
+            context,
+            stub_module,
+            overwrite_existing_annotations,
+        )
         transformer = ApplyTypeAnnotationsVisitor(context)
         transformed_source_module = transformer.transform_module(source_module)
     except Exception as exception:
@@ -152,15 +158,18 @@ def apply_stub_using_libcst(stub: str, source: str) -> str:
 
 
 def apply_stub_handler(args: argparse.Namespace, stdout: IO, stderr: IO) -> None:
-    args.existing_annotation_strategy = ExistingAnnotationStrategy.REPLICATE
     stub = get_stub(args, stdout, stderr)
     if stub is None:
         complain_about_no_traces(args, stderr)
         return
     module = args.module_path[0]
     mod = importlib.import_module(module)
     source_path = Path(inspect.getfile(mod))
-    source_with_types = apply_stub_using_libcst(stub=stub.render(), source=source_path.read_text())
+    source_with_types = apply_stub_using_libcst(
+        stub=stub.render(),
+        source=source_path.read_text(),
+        overwrite_existing_annotations=args.existing_annotation_strategy == ExistingAnnotationStrategy.IGNORE,
+    )
     source_path.write_text(source_with_types)
     print(source_with_types, file=stdout)
 
@@ -297,6 +306,14 @@ def main(argv: List[str], stdout: IO, stderr: IO) -> int:
         default=False,
         help='Print to stderr the numbers of traces stubs are based on'
         )
+    apply_parser.add_argument(
+        "--ignore-existing-annotations",
+        action="store_const",
+        dest="existing_annotation_strategy",
+        default=ExistingAnnotationStrategy.REPLICATE,
+        const=ExistingAnnotationStrategy.IGNORE,
+        help="Ignore existing annotations when applying stubs from traces.",
+    )
     apply_parser.set_defaults(handler=apply_stub_handler)
 
     stub_parser = subparsers.add_parser(

setup.py

@@ -45,7 +45,7 @@ def get_version(root_path):
         ]
     },
     python_requires='>=3.6',
-    install_requires=['mypy_extensions', 'libcst>=0.3.4'],
+    install_requires=['mypy_extensions', 'libcst>=0.3.5'],
     classifiers=[
         'Development Status :: 5 - Production/Stable',
         'Intended Audience :: Developers',

tests/test_cli.py

@@ -408,7 +408,11 @@ def no_stub(a):
         def uses_union(d: Union[int, bool]) -> None:
           return None
     """
-    assert cli.apply_stub_using_libcst(textwrap.dedent(stub), textwrap.dedent(source)) == textwrap.dedent(expected)
+    assert cli.apply_stub_using_libcst(
+        textwrap.dedent(stub),
+        textwrap.dedent(source),
+        overwrite_existing_annotations=False,
+    ) == textwrap.dedent(expected)
 
 
 def test_apply_stub_using_libcst__exception(stdout, stderr):
@@ -419,4 +423,30 @@ def my_test_function(
         def my_test_function(a: int, b: str) -> bool: ...
     """
     with pytest.raises(cli.HandlerError):
-        cli.apply_stub_using_libcst(textwrap.dedent(stub), textwrap.dedent(erroneous_source))
+        cli.apply_stub_using_libcst(
+            textwrap.dedent(stub),
+            textwrap.dedent(erroneous_source),
+            overwrite_existing_annotations=False,
+        )
+
+
+def test_apply_stub_using_libcst__overwrite_existing_annotations():
+    source = """
+        def has_annotations(x: int) -> str:
+          return 1 in x
+    """
+    stub = """
+        from typing import List
+        def has_annotations(x: List[int]) -> bool: ...
+    """
+    expected = """
+        from typing import List
+
+        def has_annotations(x: List[int]) -> bool:
+          return 1 in x
+    """
+    assert cli.apply_stub_using_libcst(
+        textwrap.dedent(stub),
+        textwrap.dedent(source),
+        overwrite_existing_annotations=True,
+    ) == textwrap.dedent(expected)

tests/test_stubs.py

@@ -397,7 +397,7 @@ class TestReplaceTypedDictsWithStubs:
                 AttributeStub(name='b', typ=str),
             ]),
         ClassStub(
-            name=f'FooBarTypedDict__RENAME_ME__NonTotal(FooBarTypedDict__RENAME_ME__, total=False)',
+            name='FooBarTypedDict__RENAME_ME__NonTotal(FooBarTypedDict__RENAME_ME__, total=False)',
             function_stubs=[],
             attribute_stubs=[
                 AttributeStub(name='c', typ=int),
@@ -723,7 +723,7 @@ def test_render_typed_dict_in_list(self):
             '',
             '',
             'class Dummy:',
-            f'    def an_instance_method(self, foo: List[\'FooTypedDict__RENAME_ME__\'], bar: int) -> int: ...'])
+            '    def an_instance_method(self, foo: List[\'FooTypedDict__RENAME_ME__\'], bar: int) -> int: ...'])
         self.maxDiff = None
         assert build_module_stubs(entries)['tests.util'].render() == expected
 
@@ -747,12 +747,12 @@ def test_render_typed_dict_base_and_subclass(self):
             '    a: int',
             '',
             '',
-            f'class FooTypedDict__RENAME_ME__NonTotal(FooTypedDict__RENAME_ME__, total=False):',
+            'class FooTypedDict__RENAME_ME__NonTotal(FooTypedDict__RENAME_ME__, total=False):',
             '    b: str',
             '',
             '',
             'class Dummy:',
-            f'    def an_instance_method(self, foo: \'FooTypedDict__RENAME_ME__NonTotal\', bar: int) -> int: ...'])
+            '    def an_instance_method(self, foo: \'FooTypedDict__RENAME_ME__NonTotal\', bar: int) -> int: ...'])
         assert build_module_stubs(entries)['tests.util'].render() == expected