Unpacking on flow constructs (return/yield) now implies 3.8+ (#2700)

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

diff --git a/src/black/__init__.py b/src/black/__init__.py
index 59018d00de469c5e276a98f84cca506e44c29d80..08c239dc15561be1ceb41a7411957289880620ac 100644 (file)
--- a/src/black/__init__.py
+++ b/src/black/__init__.py
@@ -1210,6 +1210,14 @@ def get_features_used(  # noqa: C901
                         if argch.type in STARS:
                             features.add(feature)
 
+        elif (
+            n.type in {syms.return_stmt, syms.yield_expr}
+            and len(n.children) >= 2
+            and n.children[1].type == syms.testlist_star_expr
+            and any(child.type == syms.star_expr for child in n.children[1].children)
+        ):
+            features.add(Feature.UNPACKING_ON_FLOW)
+
         # Python 2 only features (for its deprecation) except for integers, see above
         elif n.type == syms.print_stmt:
             features.add(Feature.PRINT_STMT)
@@ -1305,7 +1313,7 @@ def assert_equivalent(src: str, dst: str, *, pass_num: int = 1) -> None:
         src_ast = parse_ast(src)
     except Exception as exc:
         raise AssertionError(
-            "cannot use --safe with this file; failed to parse source file."
+            f"cannot use --safe with this file; failed to parse source file: {exc}"
         ) from exc
 
     try: