`--detach-process` doesn't work on standalone CLI (but works fine from `spawn` in the SDK)

[m-decoster]

Describe the bug The CLI flag --detach-process does nothing, since the default value is already set to true here.

I noticed that I couldn't get the viewer to not detach using the CLI. In the line linked above, the default value is set to true, which, if I'm not mistaken, means that even if the flag isn't passed, detach_process will also be true.

Apologies if I'm missing something, it wasn't entirely clear to me where this value is set.

To Reproduce Steps to reproduce the behavior:

1. Create a script which only purpose is to start rerun (see below).
2. Kill the script.
3. Rerun will keep running.

Expected behavior I expect the viewer to not detach when I don't pass this flag.

Screenshots N/A

Backtrace N/A

Desktop (please complete the following information):

• OS: Ubuntu 24.04

Rerun version

rerun-cli 0.26.2 (base lance map_view nasm native_viewer oss_server re_server release_full release_no_web_viewer web_viewer) [rustc 1.88.0 (6b00bc388 2025-06-23), LLVM 20.1.5] x86_64-unknown-linux-gnu release-0.26.2 e3c279d, built 2025-10-27T10:38:18.139141282Z
Video features: av1 default ffmpeg nasm serde

Additional context

[Wumpf]

the code you linked to is the Rust APIs struct spawn configure struct, i.e. the argument that's expected when calling spawn in Rust. The default for the CLI is in fact opt-in as it should be, that's over here

However, trying this out it doesn't seem to do anything either way from the CLI. Detaching via the API works fine though, just tried this:

from time import sleep
import rerun as rr

rr.init("test", spawn=False)
rr.spawn(detach_process=False)

sleep(1000)

and killing the process kills Rerun as expected

So outcome is the same: rerun --detach-process doesn't seem to have an effect when starting Rerun on the CLI, I don't get control back to the command line and cmd/ctrl+c kills the Viewer when it shouldn't 🤔