From 95e77cb5590a1499d3aa4cf7fe60481347191c35 Mon Sep 17 00:00:00 2001 From: Shantanu <12621235+hauntsaninja@users.noreply.github.com> Date: Fri, 28 Jan 2022 16:57:05 -0800 Subject: [PATCH] Fix arithmetic stability issue (#2817) It turns out "simple_stmt" isn't that simple: it can contain multiple statements separated by semicolons. Invisible parenthesis logic for arithmetic expressions only looked at the first child of simple_stmt. This causes instability in the presence of semicolons, since the next run through the statement following the semicolon will be the first child of another simple_stmt. I believe this along with #2572 fix the known stability issues. --- CHANGES.md | 1 + src/black/linegen.py | 10 +++++++--- src/black/nodes.py | 7 +++---- 3 files changed, 11 insertions(+), 7 deletions(-) diff --git a/CHANGES.md b/CHANGES.md index 274c564..b57a360 100644 --- a/CHANGES.md +++ b/CHANGES.md @@ -24,6 +24,7 @@ and the first release covered by our new stability policy. - Don't add whitespace for attribute access on hexadecimal, binary, octal, and complex literals (#2799) - Treat blank lines in stubs the same inside top-level `if` statements (#2820) +- Fix unstable formatting with semicolons and arithmetic expressions (#2817) ### Parser diff --git a/src/black/linegen.py b/src/black/linegen.py index b572ed0..495d323 100644 --- a/src/black/linegen.py +++ b/src/black/linegen.py @@ -7,7 +7,7 @@ from typing import Collection, Iterator, List, Optional, Set, Union from black.nodes import WHITESPACE, RARROW, STATEMENT, STANDALONE_COMMENT from black.nodes import ASSIGNMENTS, OPENING_BRACKETS, CLOSING_BRACKETS -from black.nodes import Visitor, syms, first_child_is_arith, ensure_visible +from black.nodes import Visitor, syms, is_arith_like, ensure_visible from black.nodes import is_docstring, is_empty_tuple, is_one_tuple, is_one_tuple_between from black.nodes import is_name_token, is_lpar_token, is_rpar_token from black.nodes import is_walrus_assignment, is_yield, is_vararg, is_multiline_string @@ -156,8 +156,12 @@ 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) + prev_type: Optional[int] = None + for child in node.children: + if (prev_type is None or prev_type == token.SEMI) and is_arith_like(child): + wrap_in_parentheses(node, child, visible=False) + prev_type = child.type + 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): diff --git a/src/black/nodes.py b/src/black/nodes.py index 51d4cb8..7466670 100644 --- a/src/black/nodes.py +++ b/src/black/nodes.py @@ -531,15 +531,14 @@ def first_leaf_column(node: Node) -> Optional[int]: return None -def first_child_is_arith(node: Node) -> bool: - """Whether first child is an arithmetic or a binary arithmetic expression""" - expr_types = { +def is_arith_like(node: LN) -> bool: + """Whether node is an arithmetic or a binary arithmetic expression""" + return node.type in { 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 is_docstring(leaf: Leaf) -> bool: -- 2.39.5