fix crash with long type annotations (#1093)

diff --git a/black.py b/black.py
index ada9b0efe1b989500cb05c1959440eca7be0f8e4..5b2e0171c484d2ed5d94ad3066d4fb2a13068ce7 100644 (file)
--- a/black.py
+++ b/black.py
@@ -2601,9 +2601,11 @@ def bracket_split_build_line(
             # Since body is a new indent level, remove spurious leading whitespace.
             normalize_prefix(leaves[0], inside_brackets=True)
             # Ensure a trailing comma for imports and standalone function arguments, but
-            # be careful not to add one after any comments.
-            no_commas = original.is_def and not any(
-                l.type == token.COMMA for l in leaves
+            # be careful not to add one after any comments or within type annotations.
+            no_commas = (
+                original.is_def
+                and opening_bracket.value == "("
+                and not any(l.type == token.COMMA for l in leaves)
             )
 
             if original.is_import or no_commas:

diff --git a/tests/data/function_trailing_comma.py b/tests/data/function_trailing_comma.py
index f2594c68ae246743348851d860ccdd8d78fd2ede..fcd81ad7d9689e74d856cd1e75b1d1c3ef7557b1 100644 (file)
--- a/tests/data/function_trailing_comma.py
+++ b/tests/data/function_trailing_comma.py
@@ -4,6 +4,11 @@ def f(a,):
 def f(a:int=1,):
     ...
 
+def xxxxxxxxxxxxxxxxxxxxxxxxxxxx() -> Set[
+    "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+]:
+    pass
+
 # output
 
 def f(a,):
@@ -12,3 +17,9 @@ def f(a,):
 
 def f(a: int = 1,):
     ...
+
+
+def xxxxxxxxxxxxxxxxxxxxxxxxxxxx() -> Set[
+    "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+]:
+    pass