From 9938c92fd72deda1156aca79946d7996a5365eaa Mon Sep 17 00:00:00 2001
From: Andrew Zhou <andrewfzhou@gmail.com>
Date: Fri, 8 May 2020 08:01:42 -0500
Subject: [PATCH] Add error on non-list target-version in config file (#1284)

---
 black.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/black.py b/black.py
index ff4f098..b3f387a 100644
--- a/black.py
+++ b/black.py
@@ -296,6 +296,12 @@ def read_pyproject_toml(
     if not config:
         return None
 
+    target_version = config.get("target_version")
+    if target_version is not None and not isinstance(target_version, list):
+        raise click.BadOptionUsage(
+            "target-version", f"Config key target-version must be a list"
+        )
+
     default_map: Dict[str, Any] = {}
     if ctx.default_map:
         default_map.update(ctx.default_map)
-- 
2.39.5