Assignment to env var in Jupyter Notebook doesn't round-trip (#2642)

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

diff --git a/src/black/linegen.py b/src/black/linegen.py
index 8cf32c973bb6a4880e543ec6a51ec06ff54dc492..4cba4164fb357f73b971ff0070fc0fd624323bc2 100644 (file)
--- a/src/black/linegen.py
+++ b/src/black/linegen.py
@@ -5,8 +5,6 @@ from functools import partial, wraps
 import sys
 from typing import Collection, Iterator, List, Optional, Set, Union
 
-from dataclasses import dataclass, field
-
 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
@@ -40,7 +38,8 @@ class CannotSplit(CannotTransform):
     """A readable split that fits the allotted line length is impossible."""
 
 
-@dataclass
+# This isn't a dataclass because @dataclass + Generic breaks mypyc.
+# See also https://github.com/mypyc/mypyc/issues/827.
 class LineGenerator(Visitor[Line]):
     """Generates reformatted Line objects.  Empty lines are not emitted.
 
@@ -48,9 +47,11 @@ class LineGenerator(Visitor[Line]):
     in ways that will no longer stringify to valid Python code on the tree.
     """
 
-    mode: Mode
-    remove_u_prefix: bool = False
-    current_line: Line = field(init=False)
+    def __init__(self, mode: Mode, remove_u_prefix: bool = False) -> None:
+        self.mode = mode
+        self.remove_u_prefix = remove_u_prefix
+        self.current_line: Line
+        self.__post_init__()
 
     def line(self, indent: int = 0) -> Iterator[Line]:
         """Generate a line.
@@ -339,7 +340,9 @@ def transform_line(
         transformers = [left_hand_split]
     else:
 
-        def rhs(line: Line, features: Collection[Feature]) -> Iterator[Line]:
+        def _rhs(
+            self: object, line: Line, features: Collection[Feature]
+        ) -> Iterator[Line]:
             """Wraps calls to `right_hand_split`.
 
             The calls increasingly `omit` right-hand trailers (bracket pairs with
@@ -366,6 +369,12 @@ def transform_line(
                 line, line_length=mode.line_length, features=features
             )
 
+        # HACK: nested functions (like _rhs) compiled by mypyc don't retain their
+        # __name__ attribute which is needed in `run_transformer` further down.
+        # Unfortunately a nested class breaks mypyc too. So a class must be created
+        # via type ... https://github.com/mypyc/mypyc/issues/884
+        rhs = type("rhs", (), {"__call__": _rhs})()
+
         if mode.experimental_string_processing:
             if line.inside_brackets:
                 transformers = [
@@ -980,7 +989,7 @@ def run_transformer(
         result.extend(transform_line(transformed_line, mode=mode, features=features))
 
     if (
-        transform.__name__ != "rhs"
+        transform.__class__.__name__ != "rhs"
         or not line.bracket_tracker.invisible
         or any(bracket.value for bracket in line.bracket_tracker.invisible)
         or line.contains_multiline_strings()