split long del statements into multiple lines (#698)

Fixes #693

diff --git a/README.md b/README.md
index b25f64fb8af79682cbda9bebf8b4b4da37e990ea..57272aefc3f85078499b4eccc204a3472dac1ca6 100644 (file)
--- a/README.md
+++ b/README.md
@@ -944,10 +944,12 @@ More details can be found in [CONTRIBUTING](CONTRIBUTING.md).
 
 ### 19.2b0
 
-* *Black* no longer normalizes numeric literals to include `_` separators.
+* long `del` statements are now split into multiple lines (#698)
+
+* *Black* no longer normalizes numeric literals to include `_` separators (#696)
 
 * new option `--target-version` to control which Python versions
-  *Black*-formatted code should target
+  *Black*-formatted code should target (#618)
 
 ### 18.9b0
 

diff --git a/black.py b/black.py
index 34bd59eacdddb8998ca7231d0c959f49f19b611e..8f50d3e217dbf1746036186691ce4cb3f7dbb1fe 100644 (file)
--- a/black.py
+++ b/black.py
@@ -1646,6 +1646,7 @@ class LineGenerator(Visitor[Line]):
         self.visit_expr_stmt = partial(v, keywords=Ø, parens=ASSIGNMENTS)
         self.visit_return_stmt = partial(v, keywords={"return"}, parens={"return"})
         self.visit_import_from = partial(v, keywords=Ø, parens={"import"})
+        self.visit_del_stmt = partial(v, keywords=Ø, parens={"del"})
         self.visit_async_funcdef = self.visit_async_stmt
         self.visit_decorated = self.visit_decorators
 
@@ -3350,7 +3351,16 @@ def assert_equivalent(src: str, dst: str) -> None:
 
             if isinstance(value, list):
                 for item in value:
-                    if isinstance(item, ast.AST):
+                    # Ignore nested tuples within del statements, because we may insert
+                    # parentheses and they change the AST.
+                    if (
+                        field == "targets"
+                        and isinstance(node, ast.Delete)
+                        and isinstance(item, ast.Tuple)
+                    ):
+                        for item in item.elts:
+                            yield from _v(item, depth + 2)
+                    elif isinstance(item, ast.AST):
                         yield from _v(item, depth + 2)
 
             elif isinstance(value, ast.AST):

diff --git a/tests/data/cantfit.py b/tests/data/cantfit.py
index 2a7cde348840ef7b1244b4924066b79680fdf1e2..0ab1575ffbcd0e6999e074e01b84ed6020b0efc3 100644 (file)
--- a/tests/data/cantfit.py
+++ b/tests/data/cantfit.py
@@ -36,6 +36,7 @@ for key in """
     if key in self.connect_kwargs:
         raise ValueError(err.format(key))
 concatenated_strings = "some strings that are" "concatenated implicitly, so if you put them on separate" "lines it will fit"
+del concatenated_strings, string_variable_name, normal_function_name, normal_name, need_more_to_make_the_line_long_enough
 
 
 # output
@@ -91,3 +92,10 @@ concatenated_strings = (
     "concatenated implicitly, so if you put them on separate"
     "lines it will fit"
 )
+del (
+    concatenated_strings,
+    string_variable_name,
+    normal_function_name,
+    normal_name,
+    need_more_to_make_the_line_long_enough,
+)