INTERNAL ERROR: Black produced different code on the second pass of the formatter

[semajson]

Describe the bug When running black over the following code:

def verify_data(number_of_messages, pdu_payload, binascii):
    udh_prefix = "test"

    # Verify the UDH header and the data_coding.
    assert pdu_payload.startswith(udh_prefix + chr(number_of_messages)), (
        "Expected PDU payload to begin with (as hex) "
        "{udh_prefix}{number_of_messages}, but was {actual}".format(
            udh_prefix=binascii.b2a_hex(udh_prefix),
            number_of_messages=binascii.b2a_hex(chr(number_of_messages)),
            actual=binascii.b2a_hex(pdu_payload)))

The error INTERNAL ERROR: Black produced different code on the second pass of the formatter is reported

To Reproduce Run black over code snippet posted above

Expected behavior Black formats the file without error

Environment :

• Version: 20.8b1
• OS and Python version: Centos 7 / Python 2.7.5 (although code was from a python 2 script, I don't think it's a python 2 specific issue)

Does this bug also happen on master? Yes, it repos on https://black.now.sh/?version=master

Additional context Output of the of the diff file:

Mode(target_versions=set(), line_length=88, string_normalization=True, experimental_string_processing=False, is_pyi=False)
--- source
+++ first pass
@@ -1,11 +1,12 @@
-
 def verify_data(number_of_messages, pdu_payload, binascii):
     udh_prefix = "test"
 
     # Verify the UDH header and the data_coding.
     assert pdu_payload.startswith(udh_prefix + chr(number_of_messages)), (
         "Expected PDU payload to begin with (as hex) "
         "{udh_prefix}{number_of_messages}, but was {actual}".format(
             udh_prefix=binascii.b2a_hex(udh_prefix),
             number_of_messages=binascii.b2a_hex(chr(number_of_messages)),
-            actual=binascii.b2a_hex(pdu_payload)))
+            actual=binascii.b2a_hex(pdu_payload),
+        )
+    )
--- first pass
+++ second pass
@@ -1,12 +1,11 @@
 def verify_data(number_of_messages, pdu_payload, binascii):
     udh_prefix = "test"
 
     # Verify the UDH header and the data_coding.
-    assert pdu_payload.startswith(udh_prefix + chr(number_of_messages)), (
-        "Expected PDU payload to begin with (as hex) "
-        "{udh_prefix}{number_of_messages}, but was {actual}".format(
-            udh_prefix=binascii.b2a_hex(udh_prefix),
-            number_of_messages=binascii.b2a_hex(chr(number_of_messages)),
-            actual=binascii.b2a_hex(pdu_payload),
-        )
+    assert pdu_payload.startswith(
+        udh_prefix + chr(number_of_messages)
+    ), "Expected PDU payload to begin with (as hex) " "{udh_prefix}{number_of_messages}, but was {actual}".format(
+        udh_prefix=binascii.b2a_hex(udh_prefix),
+        number_of_messages=binascii.b2a_hex(chr(number_of_messages)),
+        actual=binascii.b2a_hex(pdu_payload),
     )

[ichard26]

Hello!

All reproduction cases in this issue format without error on master. The fixing commit was 8672af3 from PR GH-2126. I'll be marking this issue as a duplicate of GH-1629 since that's what GH-2126 aimed to fix and it's highly likely this issue falls under GH-1629.

Since we use the issue tracker as a reflection of what's on master, I'll be closing this issue. If you have any issues, especially with the new (but stable) output, please open a new issue. Oh and the fix should be available in a published release soon, see GH-2125 for more info.

Thank you for reporting!