Don't freeze when multiple comments directly precede # fmt: off

Fixes #371

README.md

@@ -820,6 +820,11 @@ More details can be found in [CONTRIBUTING](CONTRIBUTING.md).
 
 ## Change Log
 
+### 18.6b4
+
+* hotfix: don't freeze when multiple comments directly precede `# fmt: off` (#371)
+
+
 ### 18.6b3
 
 * typing stub files (`.pyi`) now have blank lines added after constants (#340)

black.py

@@ -2608,7 +2608,7 @@ def convert_one_fmt_off_pair(node: Node) -> bool:
                 )
                 return True
 
-            previous_consumed += comment.consumed
+            previous_consumed = comment.consumed
 
     return False
 

tests/data/fmtonoff.py

@@ -11,6 +11,10 @@
                          Y, Z)
 # fmt: on
 f'trigger 3.6 mode'
+# Comment 1
+
+# Comment 2
+
 # fmt: off
 def func_no_args():
   a; b; c
@@ -159,6 +163,10 @@ def single_literal_yapf_disable():
                          Y, Z)
 # fmt: on
 f"trigger 3.6 mode"
+# Comment 1
+
+# Comment 2
+
 # fmt: off
 def func_no_args():
   a; b; c