* fix(daemon): skip machine-scope fallback on permission-denied bus errors; fall back to --user when sudo machine scope fails
When systemctl --user fails with "Failed to connect to bus: Permission
denied", the machine-scope fallback is now skipped. A Permission denied
error means the bus socket exists but the process cannot connect to it,
so --machine user@ would hit the same wall.
Additionally, the sudo path in execSystemctlUser now tries machine scope
first but falls through to a direct --user attempt if it fails, instead
of returning the error immediately.
Fixes#61959
* fix(daemon): guard against double machine-scope call when sudo path already tried it
When SUDO_USER is set and machine scope fails with a non-permission-denied
bus error, execution falls through to the direct --user attempt. If that
also fails with a bus-unavailable message, shouldFallbackToMachineUserScope
returns true and machine scope is tried a second time -- a redundant exec
that was never reachable before this PR opened the fallthrough path.
Add machineScopeAlreadyTried flag and include it in the bottom-fallback
guard condition so the second call is skipped when machine scope was
already attempted in the sudo branch.
Add regression test asserting exactly 2 execFile calls in this scenario.
* fix: keep sudo systemctl scoped
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Co-authored-by: Peter Steinberger <steipete@gmail.com>