Black fails to format over-length line containing walrus operator (works on master)

Describe the bug As per title - lines longer than 88 containing a walrus operator fail to be formatted.

It works on master though (tested in the online version)

To Reproduce Steps to reproduce the behavior:

1. Take this code

longnamelongnamelongnamelongnamelongnamelongnamelongnamelongname = 5
if x := longnamelongnamelongnamelongnamelongnamelongnamelongnamelongname + longnamelongnamelongnamelongnamelongnamelongnamelongnamelongname:
    print(x)

1. Run Black on it
2. See error

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

Environment (please complete the following information):

• Version: 19.10b0
• OS and Python version: windows 10, python 3.8.0

Does this bug also happen on master? It does work on master - tested on online version. Looks like we just need a new release.

[aberrier]

Do we have an approximate time of when the release will come up? 😃

[jcusick13]

I’m also running into an issue with the walrus operator, though it seems to be independent of line length. When running black on a file, it fails on this line

while (foo := my_func(bar)) >= 0:

providing

cannot use --safe with this file; failed to parse source file. AST error message: invalid syntax (<unknown>, line 12)

By removing the walrus operator from that line, black is successfully able to format the file.

Environment

• black version 19.10b
• Python 3.8.0
• Ubuntu 18.04.3

Does this bug happen on master? No, this bug does not occur on the master branch. I agree with Martin about the new release.

Thanks for all of the work thus far! 👍