On Thu, 11 Oct 2018 at 08:57, Klaus-Dieter Bauer
<bauer.klaus.dieter@gmail.com> wrote:

>     M-x eval-expression RET
>       (make-process :name "test" :command '("c:/No Such Command"))
>
> will merely display in the echo-area message:
>
>     eval: Spawning child process: Invalid argument

The confusing thing here is that the error is signaled between
block_input()...unblock_input(), which prevents the debugger from
triggering. E.g., the "-unless-debug" part in the expression below
appears not to work, even though the error flows normally in other
respects:

(condition-case-unless-debug err
    (make-process :name "test" :command '("c:/No Such Command"))
  (error (list :error err)))
;=> (:error (file-error "Spawning child process" "Invalid argument"))

The attached patch fixes this by moving the signal to after the unblock_input().