Function default_runner_root 

pub fn default_runner_root(
    app_paths: &AppPaths,
) -> Result<LocalAbsolutePath, RunnerRootError>

The platform default host runner root for this machine.

macOS and Linux keep the directory attempts have always used — AppPaths::runtime_dir — byte for byte. Only Windows had a path-length problem, and relocating the other two would move live workspaces for no reason (02-target-architecture.md, “Platform defaults”).

Errors

RunnerRootError::ApplicationRuntimeDirectoryUnusable or RunnerRootError::NonUnicode when the resolved application runtime directory is not a storable local path, which for a discovered layout means the account’s own data directory is unusable.