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

[trygveaa]

Describe the bug A clear and concise description of what the bug is.

To Reproduce Steps to reproduce the behavior:

1. Take this file: https://github.com/wee-slack/wee-slack/blob/bf9ef6f4bcd580a9b4ba858537d0a99cae7bb87e/wee_slack.py
2. Run Black on it with these arguments: black wee_slack.py
3. See error:

error: cannot format wee_slack.py: INTERNAL ERROR: Black produced different code on the second pass of the formatter.  Please report a bug on https://github.com/psf/black/issues.  This diff might be helpful: /tmp/blk_wg5ef8k0.log
Oh no! 💥 💔 💥
1 file failed to reformat.

blk_wg5ef8k0.log

Expected behavior A clear and concise description of what you expected to happen.

Black should format the file.

Environment (please complete the following information):

• Version: 20.8b1 and master
• OS and Python version: Linux/Python 3.9.2

Does this bug also happen on master? To answer this, you have two options:

Yes

[trygveaa]

If I run black --fast, it does manage to reformat. If I then touch the file (otherwise black won't do anything the second time) and run black again (with or without --fast), I get this diff:

diff --git a/wee_slack.py b/wee_slack.py
index d0290ae..c9d0c60 100644
--- a/wee_slack.py
+++ b/wee_slack.py
@@ -3279,10 +3279,14 @@ class SlackMessage(object):
         if self.message_json.get("mrkdwn", True):
             text = render_formatting(text)
 
-        if self.message_json.get("subtype") in (
-            "channel_join",
-            "group_join",
-        ) and self.message_json.get("inviter"):
+        if (
+            self.message_json.get("subtype")
+            in (
+                "channel_join",
+                "group_join",
+            )
+            and self.message_json.get("inviter")
+        ):
             inviter_id = self.message_json.get("inviter")
             text += " by invitation from <@{}>".format(inviter_id)
 

If I run black subsequent times after that, it doesn't change anything more.

[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!