Merge pull request #406 from MarcoGorelli/dequote-annotations

quoted annotations + `from __future__ import annotations`

pyupgrade/_plugins/typing_pep563.py

@@ -0,0 +1,168 @@
+import ast
+import functools
+import sys
+from typing import Iterable
+from typing import List
+from typing import Optional
+from typing import Sequence
+from typing import Tuple
+
+from tokenize_rt import Offset
+
+from pyupgrade._ast_helpers import ast_to_offset
+from pyupgrade._data import register
+from pyupgrade._data import State
+from pyupgrade._data import Token
+from pyupgrade._data import TokenFunc
+
+
+def _supported_version(state: State) -> bool:
+    return (
+        state.settings.min_version >= (3, 10) or
+        'annotations' in state.from_imports['__future__']
+    )
+
+
+def _dequote(i: int, tokens: List[Token], *, new: str) -> None:
+    tokens[i] = tokens[i]._replace(src=new)
+
+
+def _get_name(node: ast.expr) -> str:
+    if isinstance(node, ast.Name):
+        return node.id
+    elif isinstance(node, ast.Attribute):
+        return node.attr
+    else:
+        raise AssertionError(f'expected Name or Attribute: {ast.dump(node)}')
+
+
+def _get_keyword_value(
+        keywords: List[ast.keyword],
+        keyword: str,
+) -> Optional[ast.expr]:
+    for kw in keywords:
+        if kw.arg == keyword:
+            return kw.value
+    else:
+        return None
+
+
+def _process_call(node: ast.Call) -> Iterable[ast.AST]:
+    name = _get_name(node.func)
+    args = node.args
+    keywords = node.keywords
+    if name == 'TypedDict':
+        if keywords:
+            for keyword in keywords:
+                yield keyword.value
+        elif len(args) != 2:  # garbage
+            pass
+        elif isinstance(args[1], ast.Dict):
+            yield from args[1].values
+        else:
+            raise AssertionError(f'expected ast.Dict: {ast.dump(args[1])}')
+    elif name == 'NamedTuple':
+        if len(args) == 2:
+            fields: Optional[ast.expr] = args[1]
+        elif keywords:
+            fields = _get_keyword_value(keywords, 'fields')
+        else:  # garbage
+            fields = None
+
+        if isinstance(fields, ast.List):
+            for elt in fields.elts:
+                if isinstance(elt, ast.Tuple) and len(elt.elts) == 2:
+                    yield elt.elts[1]
+        elif fields is not None:
+            raise AssertionError(f'expected ast.List: {ast.dump(fields)}')
+    elif name in {
+        'Arg',
+        'DefaultArg',
+        'NamedArg',
+        'DefaultNamedArg',
+        'VarArg',
+        'KwArg',
+    }:
+        if args:
+            yield args[0]
+        else:
+            keyword_value = _get_keyword_value(keywords, 'type')
+            if keyword_value is not None:
+                yield keyword_value
+
+
+def _process_subscript(node: ast.Subscript) -> Iterable[ast.AST]:
+    name = _get_name(node.value)
+    if name == 'Annotated':
+        if sys.version_info >= (3, 9):  # pragma: no cover (py39+)
+            node_slice: ast.expr = node.slice
+        elif isinstance(node.slice, ast.Index):  # pragma: no cover (<py39)
+            node_slice = node.slice.value
+        else:  # pragma: no cover (<py39)
+            pass  # unexpected slice type
+
+        if isinstance(node_slice, ast.Tuple):
+            if node_slice.elts:
+                yield node_slice.elts[0]
+        else:
+            raise AssertionError(f'expected ast.Tuple: {ast.dump(node_slice)}')
+    elif name != 'Literal':
+        yield node.slice
+
+
+def _replace_string_literal(
+        annotation: ast.expr,
+) -> Iterable[Tuple[Offset, TokenFunc]]:
+    nodes: List[ast.AST] = [annotation]
+    while nodes:
+        node = nodes.pop()
+        if isinstance(node, ast.Call):
+            nodes.extend(_process_call(node))
+        elif isinstance(node, ast.Subscript):
+            nodes.extend(_process_subscript(node))
+        elif isinstance(node, ast.Str):
+            func = functools.partial(_dequote, new=node.s)
+            yield ast_to_offset(node), func
+        else:
+            for name in node._fields:
+                value = getattr(node, name)
+                if isinstance(value, ast.AST):
+                    nodes.append(value)
+                elif isinstance(value, list):
+                    nodes.extend(value)
+
+
+def _process_args(
+        args: Sequence[Optional[ast.arg]],
+) -> Iterable[Tuple[Offset, TokenFunc]]:
+    for arg in args:
+        if arg is not None and arg.annotation is not None:
+            yield from _replace_string_literal(arg.annotation)
+
+
+@register(ast.FunctionDef)
+def visit_FunctionDef(
+        state: State,
+        node: ast.FunctionDef,
+        parent: ast.AST,
+) -> Iterable[Tuple[Offset, TokenFunc]]:
+    if not _supported_version(state):
+        return
+
+    yield from _process_args([node.args.vararg, node.args.kwarg])
+    yield from _process_args(node.args.args)
+    yield from _process_args(node.args.kwonlyargs)
+    yield from _process_args(getattr(node.args, 'posonlyargs', []))
+    if node.returns is not None:
+        yield from _replace_string_literal(node.returns)
+
+
+@register(ast.AnnAssign)
+def visit_AnnAssign(
+        state: State,
+        node: ast.AnnAssign,
+        parent: ast.AST,
+) -> Iterable[Tuple[Offset, TokenFunc]]:
+    if not _supported_version(state):
+        return
+    yield from _replace_string_literal(node.annotation)