[TSP] Double errors with pyrefly

[kinto0]

Environment data

TSP settings:

    "python.analysis.enableExternalTypeServer": true,
    "python.analysis.typeServerArguments": [
        "tsp"
    ],
    "python.analysis.typeServerExecutable": "/Users/kylei/projects/test/.venv/bin/pyrefly"

• Pylance version: 2026.1.102
• OS: Mac
• Python version (& distribution if applicable, e.g. Anaconda): 3.13.8 using UV
• Pyrefly version:

(test) testkylei@kylei-mbp test % pyrefly --version
pyrefly 0.58.0

Code Snippet

1 + ""

->
see two pyrefly errors appear

Expected behavior

One pyrefly error

Logs

2026-03-25 15:30:57.318 [error] (44796): BG(test): TS:  INFO Published 2 diagnostics for file:///Users/kylei/projects/test/test.py

[rchiodo]

I don't reproduce this problem?

Do you maybe have the Pyrefly extension installed too?

[kinto0]

I don't reproduce this problem?

Do you maybe have the Pyrefly extension installed too?

that would be funny, but unfortunately no

I see this log message like in the issue summary:

2026-03-31 22:07:13.184 [error] (38962): BG(test): TS:  INFO Published 2 diagnostics for file:///Users/kylei/projects/test/test.py

what's the easiest way to see the TSP traffic to debug this?

[rchiodo]

what's the easiest way to see the TSP traffic to debug this?

I guess modify Pyrefly's TSP handlers to eprintln? All of its output should show up in the Python Language Server log.

[rchiodo]

Otherwise we don't log TSP messages at the moment on the client side. I should add something for that though.