X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/a68dd928e681cc6a921f39b2c3fc1f05e15afdd3..223268aaae19ef53254209db43721a18c4295245:/black.py?ds=inline

diff --git a/black.py b/black.py
index eb99a41..913fe8d 100644
--- a/black.py
+++ b/black.py
@@ -409,9 +409,10 @@ def format_str(src_contents: str, line_length: int) -> FileContent:
     """
     src_node = lib2to3_parse(src_contents)
     dst_contents = ""
-    lines = LineGenerator()
-    elt = EmptyLineTracker()
+    future_imports = get_future_imports(src_node)
     py36 = is_python36(src_node)
+    lines = LineGenerator(remove_u_prefix=py36 or "unicode_literals" in future_imports)
+    elt = EmptyLineTracker()
     empty_line = Line()
     after = 0
     for current_line in lines.visit(src_node):
@@ -599,6 +600,22 @@ TEST_DESCENDANTS = {
     syms.term,
     syms.power,
 }
+ASSIGNMENTS = {
+    "=",
+    "+=",
+    "-=",
+    "*=",
+    "@=",
+    "/=",
+    "%=",
+    "&=",
+    "|=",
+    "^=",
+    "<<=",
+    ">>=",
+    "**=",
+    "//=",
+}
 COMPREHENSION_PRIORITY = 20
 COMMA_PRIORITY = 18
 TERNARY_PRIORITY = 16
@@ -631,8 +648,8 @@ class BracketTracker:
     bracket_match: Dict[Tuple[Depth, NodeType], Leaf] = Factory(dict)
     delimiters: Dict[LeafID, Priority] = Factory(dict)
     previous: Optional[Leaf] = None
-    _for_loop_variable: bool = False
-    _lambda_arguments: bool = False
+    _for_loop_variable: int = 0
+    _lambda_arguments: int = 0
 
     def mark(self, leaf: Leaf) -> None:
         """Mark `leaf` with bracket-related metadata. Keep track of delimiters.
@@ -694,7 +711,7 @@ class BracketTracker:
         """
         if leaf.type == token.NAME and leaf.value == "for":
             self.depth += 1
-            self._for_loop_variable = True
+            self._for_loop_variable += 1
             return True
 
         return False
@@ -703,7 +720,7 @@ class BracketTracker:
         """See `maybe_increment_for_loop_variable` above for explanation."""
         if self._for_loop_variable and leaf.type == token.NAME and leaf.value == "in":
             self.depth -= 1
-            self._for_loop_variable = False
+            self._for_loop_variable -= 1
             return True
 
         return False
@@ -716,7 +733,7 @@ class BracketTracker:
         """
         if leaf.type == token.NAME and leaf.value == "lambda":
             self.depth += 1
-            self._lambda_arguments = True
+            self._lambda_arguments += 1
             return True
 
         return False
@@ -725,7 +742,7 @@ class BracketTracker:
         """See `maybe_increment_lambda_arguments` above for explanation."""
         if self._lambda_arguments and leaf.type == token.COLON:
             self.depth -= 1
-            self._lambda_arguments = False
+            self._lambda_arguments -= 1
             return True
 
         return False
@@ -994,8 +1011,9 @@ class Line:
             and subscript_start.type == syms.subscriptlist
         ):
             subscript_start = child_towards(subscript_start, leaf)
-        return subscript_start is not None and any(
-            n.type in TEST_DESCENDANTS for n in subscript_start.pre_order()
+        return (
+            subscript_start is not None
+            and any(n.type in TEST_DESCENDANTS for n in subscript_start.pre_order())
         )
 
     def __str__(self) -> str:
@@ -1154,6 +1172,7 @@ class LineGenerator(Visitor[Line]):
     in ways that will no longer stringify to valid Python code on the tree.
     """
     current_line: Line = Factory(Line)
+    remove_u_prefix: bool = False
 
     def line(self, indent: int = 0, type: Type[Line] = Line) -> Iterator[Line]:
         """Generate a line.
@@ -1221,6 +1240,7 @@ class LineGenerator(Visitor[Line]):
             else:
                 normalize_prefix(node, inside_brackets=any_open_brackets)
                 if node.type == token.STRING:
+                    normalize_string_prefix(node, remove_u_prefix=self.remove_u_prefix)
                     normalize_string_quotes(node)
                 if node.type not in WHITESPACE:
                     self.current_line.append(node)
@@ -1252,7 +1272,7 @@ class LineGenerator(Visitor[Line]):
         """Visit a statement.
 
         This implementation is shared for `if`, `while`, `for`, `try`, `except`,
-        `def`, `with`, `class`, and `assert`.
+        `def`, `with`, `class`, `assert` and assignments.
 
         The relevant Python language `keywords` for a given statement will be
         NAME leaves within it. This methods puts those on a separate line.
@@ -1358,7 +1378,9 @@ class LineGenerator(Visitor[Line]):
         v = self.visit_stmt
         Ø: Set[str] = set()
         self.visit_assert_stmt = partial(v, keywords={"assert"}, parens={"assert", ","})
-        self.visit_if_stmt = partial(v, keywords={"if", "else", "elif"}, parens={"if"})
+        self.visit_if_stmt = partial(
+            v, keywords={"if", "else", "elif"}, parens={"if", "elif"}
+        )
         self.visit_while_stmt = partial(v, keywords={"while", "else"}, parens={"while"})
         self.visit_for_stmt = partial(v, keywords={"for", "else"}, parens={"for", "in"})
         self.visit_try_stmt = partial(
@@ -1368,6 +1390,8 @@ class LineGenerator(Visitor[Line]):
         self.visit_with_stmt = partial(v, keywords={"with"}, parens=Ø)
         self.visit_funcdef = partial(v, keywords={"def"}, parens=Ø)
         self.visit_classdef = partial(v, keywords={"class"}, parens=Ø)
+        self.visit_expr_stmt = partial(v, keywords=Ø, parens=ASSIGNMENTS)
+        self.visit_return_stmt = partial(v, keywords={"return"}, parens={"return"})
         self.visit_async_funcdef = self.visit_async_stmt
         self.visit_decorated = self.visit_decorators
 
@@ -2140,6 +2164,22 @@ def normalize_prefix(leaf: Leaf, *, inside_brackets: bool) -> None:
     leaf.prefix = ""
 
 
+def normalize_string_prefix(leaf: Leaf, remove_u_prefix: bool = False) -> None:
+    """Make all string prefixes lowercase.
+
+    If remove_u_prefix is given, also removes any u prefix from the string.
+
+    Note: Mutates its argument.
+    """
+    match = re.match(r"^([furbFURB]*)(.*)$", leaf.value, re.DOTALL)
+    assert match is not None, f"failed to match string {leaf.value!r}"
+    orig_prefix = match.group(1)
+    new_prefix = orig_prefix.lower()
+    if remove_u_prefix:
+        new_prefix = new_prefix.replace("u", "")
+    leaf.value = f"{new_prefix}{match.group(2)}"
+
+
 def normalize_string_quotes(leaf: Leaf) -> None:
     """Prefer double quotes but only if it doesn't cause more escaping.
 
@@ -2237,6 +2277,7 @@ def maybe_make_parens_invisible_in_atom(node: LN) -> bool:
         node.type != syms.atom
         or is_empty_tuple(node)
         or is_one_tuple(node)
+        or is_yield(node)
         or max_delimiter_priority_in_atom(node) >= COMMA_PRIORITY
     ):
         return False
@@ -2287,12 +2328,33 @@ def is_one_tuple(node: LN) -> bool:
     )
 
 
+def is_yield(node: LN) -> bool:
+    """Return True if `node` holds a `yield` or `yield from` expression."""
+    if node.type == syms.yield_expr:
+        return True
+
+    if node.type == token.NAME and node.value == "yield":  # type: ignore
+        return True
+
+    if node.type != syms.atom:
+        return False
+
+    if len(node.children) != 3:
+        return False
+
+    lpar, expr, rpar = node.children
+    if lpar.type == token.LPAR and rpar.type == token.RPAR:
+        return is_yield(expr)
+
+    return False
+
+
 def is_vararg(leaf: Leaf, within: Set[NodeType]) -> bool:
     """Return True if `leaf` is a star or double star in a vararg or kwarg.
 
     If `within` includes VARARGS_PARENTS, this applies to function signatures.
-    If `within` includes COLLECTION_LIBERALS_PARENTS, it applies to right
-    hand-side extended iterable unpacking (PEP 3132) and additional unpacking
+    If `within` includes UNPACKING_PARENTS, it applies to right hand-side
+    extended iterable unpacking (PEP 3132) and additional unpacking
     generalizations (PEP 448).
     """
     if leaf.type not in STARS or not leaf.parent:
@@ -2380,6 +2442,41 @@ def is_python36(node: Node) -> bool:
     return False
 
 
+def get_future_imports(node: Node) -> Set[str]:
+    """Return a set of __future__ imports in the file."""
+    imports = set()
+    for child in node.children:
+        if child.type != syms.simple_stmt:
+            break
+        first_child = child.children[0]
+        if isinstance(first_child, Leaf):
+            # Continue looking if we see a docstring; otherwise stop.
+            if (
+                len(child.children) == 2
+                and first_child.type == token.STRING
+                and child.children[1].type == token.NEWLINE
+            ):
+                continue
+            else:
+                break
+        elif first_child.type == syms.import_from:
+            module_name = first_child.children[1]
+            if not isinstance(module_name, Leaf) or module_name.value != "__future__":
+                break
+            for import_from_child in first_child.children[3:]:
+                if isinstance(import_from_child, Leaf):
+                    if import_from_child.type == token.NAME:
+                        imports.add(import_from_child.value)
+                else:
+                    assert import_from_child.type == syms.import_as_names
+                    for leaf in import_from_child.children:
+                        if isinstance(leaf, Leaf) and leaf.type == token.NAME:
+                            imports.add(leaf.value)
+        else:
+            break
+    return imports
+
+
 PYTHON_EXTENSIONS = {".py"}
 BLACKLISTED_DIRECTORIES = {
     "build", "buck-out", "dist", "_build", ".git", ".hg", ".mypy_cache", ".tox", ".venv"