From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Thu, 13 Aug 2020 02:12:21 +0000 (-0700)
Subject: Remove slow assertion (#1592)
X-Git-Url: https://git.madduck.net/etc/vim.git/commitdiff_plain/f825e7ef28c65689e06453d0c3a00310b90cdfdb?hp=b59a5246577346e6da2cc2802015f08524abf545

Remove slow assertion (#1592)

Partial fix for #1581

This assertion produces behavior quadratic in the number of leaves in a line, which is making Black extremely slow on files with very long expressions. On my benchmark file this change makes Black 10x faster.
---

diff --git a/src/black/__init__.py b/src/black/__init__.py
index 930f2cb..7ce2ac8 100644
--- a/src/black/__init__.py
+++ b/src/black/__init__.py
@@ -4594,8 +4594,6 @@ def append_leaves(new_line: Line, old_line: Line, leaves: List[Leaf]) -> None:
         set(@leaves) is a subset of set(@old_line.leaves).
     """
     for old_leaf in leaves:
-        assert old_leaf in old_line.leaves
-
         new_leaf = Leaf(old_leaf.type, old_leaf.value)
         replace_child(old_leaf, new_leaf)
         new_line.append(new_leaf)