Closes#47489
The search worker pool was sized as `num_cpus - 1`, which spawned zero
workers when a devcontainer exposed only 1 CPU. All search channels
closed immediately and the search yielded zero results, while file
finder and LSP symbols worked fine.
The fix ensures at least 1 worker is always spawned: `(num_cpus -
1).max(1)`. A `num_cpus` override on `TestDispatcher` and a new test
reproduce the bug with `server_cx.executor().set_num_cpus(1)`.
## Manual testing
Add a `.devcontainer/` directory to a new project with these files:
```
// docker-compose.yml
services:
dev:
image: debian:bookworm-slim
cpuset: "0"
volumes:
- ..:/workspace:cached
command: sleep infinity
```
```
// devcontainer.json
{
"name": "zed-sandbox (1 CPU)",
"dockerComposeFile": "docker-compose.yml",
"service": "dev",
"workspaceFolder": "/workspace"
}
```
Build zed and point it at the new project:
```
cargo run -p zed -- ~/Repos/zed-sandbox-project
```
Open the built-in terminal, confirm `nproc` prints `1`.
Finally, run a project search (`Cmd+Shift+F`) and search for contents
that exist in it.
Results should appear 🎉
Release Notes:
- Fixed project search returning no results in devcontainers with a
single visible CPU.
Oliver Azevedo Barnes
9d40c471a0