Wrap arithmetic and binary arithmetic expressions in invisible parentheses (#2001)

[etc/vim.git] / src / black / __init__.py

diff --git a/src/black/__init__.py b/src/black/__init__.py
index 7f727b18bf0366f4164ad8dc49a5e1c9f3aa8394..6919468609ce34c6079a27c0794120b54c57acf2 100644 (file)
--- a/src/black/__init__.py
+++ b/src/black/__init__.py
@@ -883,7 +883,7 @@ def format_file_in_place(
         dst_name = f"{src}\t{now} +0000"
         diff_contents = diff(src_contents, dst_contents, src_name, dst_name)
 
-        if write_back == write_back.COLOR_DIFF:
+        if write_back == WriteBack.COLOR_DIFF:
             diff_contents = color_diff(diff_contents)
 
         with lock or nullcontext():
@@ -1480,7 +1480,7 @@ class Line:
     comments: Dict[LeafID, List[Leaf]] = field(default_factory=dict)
     bracket_tracker: BracketTracker = field(default_factory=BracketTracker)
     inside_brackets: bool = False
-    should_split: bool = False
+    should_split_rhs: bool = False
     magic_trailing_comma: Optional[Leaf] = None
 
     def append(self, leaf: Leaf, preformatted: bool = False) -> None:
@@ -1792,7 +1792,7 @@ class Line:
             mode=self.mode,
             depth=self.depth,
             inside_brackets=self.inside_brackets,
-            should_split=self.should_split,
+            should_split_rhs=self.should_split_rhs,
             magic_trailing_comma=self.magic_trailing_comma,
         )
 
@@ -2049,6 +2049,8 @@ class LineGenerator(Visitor[Line]):
 
     def visit_simple_stmt(self, node: Node) -> Iterator[Line]:
         """Visit a statement without nested statements."""
+        if first_child_is_arith(node):
+            wrap_in_parentheses(node, node.children[0], visible=False)
         is_suite_like = node.parent and node.parent.type in STATEMENT
         if is_suite_like:
             if self.mode.is_pyi and is_stub_body(node):
@@ -2712,7 +2714,8 @@ def transform_line(
     transformers: List[Transformer]
     if (
         not line.contains_uncollapsable_type_comments()
-        and not (line.should_split or line.magic_trailing_comma)
+        and not line.should_split_rhs
+        and not line.magic_trailing_comma
         and (
             is_line_short_enough(line, line_length=mode.line_length, line_str=line_str)
             or line.contains_unsplittable_type_ignore()
@@ -4386,7 +4389,7 @@ class StringParenWrapper(CustomSplitMapMixin, BaseStringSplitter):
             mode=line.mode,
             depth=line.depth + 1,
             inside_brackets=True,
-            should_split=line.should_split,
+            should_split_rhs=line.should_split_rhs,
             magic_trailing_comma=line.magic_trailing_comma,
         )
         string_leaf = Leaf(token.STRING, string_value)
@@ -5009,7 +5012,7 @@ def bracket_split_build_line(
         for comment_after in original.comments_after(leaf):
             result.append(comment_after, preformatted=True)
     if is_body and should_split_line(result, opening_bracket):
-        result.should_split = True
+        result.should_split_rhs = True
     return result
 
 
@@ -5612,6 +5615,17 @@ def unwrap_singleton_parenthesis(node: LN) -> Optional[LN]:
     return wrapped
 
 
+def first_child_is_arith(node: Node) -> bool:
+    """Whether first child is an arithmetic or a binary arithmetic expression"""
+    expr_types = {
+        syms.arith_expr,
+        syms.shift_expr,
+        syms.xor_expr,
+        syms.and_expr,
+    }
+    return bool(node.children and node.children[0].type in expr_types)
+
+
 def wrap_in_parentheses(parent: Node, child: LN, *, visible: bool = True) -> None:
     """Wrap `child` in parentheses.
 
@@ -5949,7 +5963,7 @@ def generate_trailers_to_omit(line: Line, line_length: int) -> Iterator[Set[Leaf
     """
 
     omit: Set[LeafID] = set()
-    if not line.should_split and not line.magic_trailing_comma:
+    if not line.magic_trailing_comma:
         yield omit
 
     length = 4 * line.depth
@@ -5971,8 +5985,7 @@ def generate_trailers_to_omit(line: Line, line_length: int) -> Iterator[Set[Leaf
             elif leaf.type in CLOSING_BRACKETS:
                 prev = line.leaves[index - 1] if index > 0 else None
                 if (
-                    line.magic_trailing_comma
-                    and prev
+                    prev
                     and prev.type == token.COMMA
                     and not is_one_tuple_between(
                         leaf.opening_bracket, leaf, line.leaves
@@ -5999,8 +6012,7 @@ def generate_trailers_to_omit(line: Line, line_length: int) -> Iterator[Set[Leaf
                 yield omit
 
             if (
-                line.magic_trailing_comma
-                and prev
+                prev
                 and prev.type == token.COMMA
                 and not is_one_tuple_between(leaf.opening_bracket, leaf, line.leaves)
             ):
@@ -6426,14 +6438,14 @@ def assert_stable(src: str, dst: str, mode: Mode) -> None:
 
 
 @mypyc_attr(patchable=True)
-def dump_to_file(*output: str) -> str:
+def dump_to_file(*output: str, ensure_final_newline: bool = True) -> str:
     """Dump `output` to a temporary file. Return path to the file."""
     with tempfile.NamedTemporaryFile(
         mode="w", prefix="blk_", suffix=".log", delete=False, encoding="utf8"
     ) as f:
         for lines in output:
             f.write(lines)
-            if lines and lines[-1] != "\n":
+            if ensure_final_newline and lines and lines[-1] != "\n":
                 f.write("\n")
     return f.name
 
@@ -6451,11 +6463,20 @@ def diff(a: str, b: str, a_name: str, b_name: str) -> str:
     """Return a unified diff string between strings `a` and `b`."""
     import difflib
 
-    a_lines = [line + "\n" for line in a.splitlines()]
-    b_lines = [line + "\n" for line in b.splitlines()]
-    return "".join(
-        difflib.unified_diff(a_lines, b_lines, fromfile=a_name, tofile=b_name, n=5)
-    )
+    a_lines = [line for line in a.splitlines(keepends=True)]
+    b_lines = [line for line in b.splitlines(keepends=True)]
+    diff_lines = []
+    for line in difflib.unified_diff(
+        a_lines, b_lines, fromfile=a_name, tofile=b_name, n=5
+    ):
+        # Work around https://bugs.python.org/issue2142
+        # See https://www.gnu.org/software/diffutils/manual/html_node/Incomplete-Lines.html
+        if line[-1] == "\n":
+            diff_lines.append(line)
+        else:
+            diff_lines.append(line + "\n")
+            diff_lines.append("\\ No newline at end of file\n")
+    return "".join(diff_lines)
 
 
 def cancel(tasks: Iterable["asyncio.Task[Any]"]) -> None:
@@ -6632,7 +6653,7 @@ def can_omit_invisible_parens(
 
     penultimate = line.leaves[-2]
     last = line.leaves[-1]
-    if line.should_split or line.magic_trailing_comma:
+    if line.magic_trailing_comma:
         try:
             penultimate, last = last_two_except(line.leaves, omit=omit_on_explode)
         except LookupError: