UnicodeEncodeError in Python application

[Andrew Clayton]

On Fri, 16 Dec 2022 13:28:24 +0100
Tobias Genannt <tobias.genannt at kappa-velorum.net> wrote:

> Hello,

Hi!,

> I'm seeing a crash in a Python application with Unit 1.29 which is not 
> happening in Unit 1.28. I'm not sure if I have to change the 
> configuration for this version bump because I didn't find an entry in 

No, you shouldn't.

> the changelog which would point to the problem.
> This is the stack trace:

[...]

>      print(f"\U0001f9ec loaded config '{path}'")
> UnicodeEncodeError: 'ascii' codec can't encode character '\U0001f9ec' in 
> position 0: ordinal not in range(128)

OK, so looks like a unicode issue.
 
> You can find the contents of the problematic file (last strack trace 
> entry) here:
> https://github.com/tobiasge/netbox-docker/blob/new-unit/docker/configuration.docker.py

I did quickly try reproducing this using current unit master and Python
3.11

{
    "listeners": {
        "[::1]:8080": {
            "pass": "applications/python"
        }
    },

    "applications": {
        "python": {
            "type": "python",
            "path": "/srv/unit/python/app/",
            "module": "app"
        }
    }
}

$ cat /srv/unit/python/app/app.py 
def application(environ, start_response):
    start_response("200 OK", [("Content-Type", "text/plain")])
    print("⚠️ test\n");
    return (b"Hello, Python on Unit!\n")

which works OK.

There aren't that many Python changes since 1.28.0

$ git log --oneline 1.28.0.. src/python/
6dae517e Python: Added "prefix" to configuration.
491d0f70 Python: Added support for Python 3.11.
6902cd14 Refactored functions that set WSGI variables.
3b970ed9 Removed dead code.
40d75c94 Optimization for the "--no-unix-sockets" case.
b0098336 Renamed a couple of members of nxt_unit_request_t.

If you're up for it, could you try reverting 491d0f70 ("Python: Added
support for Python 3.11.")?

$ git clone https://github.com/nginx/unit.git
$ cd unit

$ git revert -n 491d0f70

(ignore the warnings...)

build unit and the python module etc and test.

If things are still broken

$ git reset --hard
$ git revert -n 6902cd14

build/install and test again.

If things are still broken, you could repeat the above with the other
commits. 

Alternatively, if you have a simple bare minimum reproducer...

> Greetings,
> Tobias

Cheers,
Andrew