1 files changed, 106 insertions, 0 deletions
diff --git a/pre_commit_hooks/check_builtin_literals.py b/pre_commit_hooks/check_builtin_literals.py
new file mode 100644
index 0000000..3fbae3e
--- /dev/null
+++ b/pre_commit_hooks/check_builtin_literals.py
@@ -0,0 +1,106 @@
+import argparse
+import ast
+from typing import List
+from typing import NamedTuple
+from typing import Optional
+from typing import Sequence
+from typing import Set
+
+
+BUILTIN_TYPES = {
+    'complex': '0j',
+    'dict': '{}',
+    'float': '0.0',
+    'int': '0',
+    'list': '[]',
+    'str': "''",
+    'tuple': '()',
+}
+
+
+class Call(NamedTuple):
+    name: str
+    line: int
+    column: int
+
+
+class Visitor(ast.NodeVisitor):
+    def __init__(
+            self,
+            ignore: Optional[Sequence[str]] = None,
+            allow_dict_kwargs: bool = True,
+    ) -> None:
+        self.builtin_type_calls: List[Call] = []
+        self.ignore = set(ignore) if ignore else set()
+        self.allow_dict_kwargs = allow_dict_kwargs
+
+    def _check_dict_call(self, node: ast.Call) -> bool:
+        return self.allow_dict_kwargs and bool(node.keywords)
+
+    def visit_Call(self, node: ast.Call) -> None:
+        if not isinstance(node.func, ast.Name):
+            # Ignore functions that are object attributes (`foo.bar()`).
+            # Assume that if the user calls `builtins.list()`, they know what
+            # they're doing.
+            return
+        if node.func.id not in set(BUILTIN_TYPES).difference(self.ignore):
+            return
+        if node.func.id == 'dict' and self._check_dict_call(node):
+            return
+        elif node.args:
+            return
+        self.builtin_type_calls.append(
+            Call(node.func.id, node.lineno, node.col_offset),
+        )
+
+
+def check_file(
+        filename: str,
+        ignore: Optional[Sequence[str]] = None,
+        allow_dict_kwargs: bool = True,
+) -> List[Call]:
+    with open(filename, 'rb') as f:
+        tree = ast.parse(f.read(), filename=filename)
+    visitor = Visitor(ignore=ignore, allow_dict_kwargs=allow_dict_kwargs)
+    visitor.visit(tree)
+    return visitor.builtin_type_calls
+
+
+def parse_ignore(value: str) -> Set[str]:
+    return set(value.split(','))
+
+
+def main(argv: Optional[Sequence[str]] = None) -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('filenames', nargs='*')
+    parser.add_argument('--ignore', type=parse_ignore, default=set())
+
+    mutex = parser.add_mutually_exclusive_group(required=False)
+    mutex.add_argument('--allow-dict-kwargs', action='store_true')
+    mutex.add_argument(
+        '--no-allow-dict-kwargs',
+        dest='allow_dict_kwargs', action='store_false',
+    )
+    mutex.set_defaults(allow_dict_kwargs=True)
+
+    args = parser.parse_args(argv)
+
+    rc = 0
+    for filename in args.filenames:
+        calls = check_file(
+            filename,
+            ignore=args.ignore,
+            allow_dict_kwargs=args.allow_dict_kwargs,
+        )
+        if calls:
+            rc = rc or 1
+        for call in calls:
+            print(
+                f'{filename}:{call.line}:{call.column}: '
+                f'replace {call.name}() with {BUILTIN_TYPES[call.name]}',
+            )
+    return rc
+
+
+if __name__ == '__main__':
+    raise SystemExit(main())