Re: [PATCH 2/6] Automatically close stderr pipes created by run_command

> Shawn O. Pearce schrieb:
>> Like the out pipe and in pipe, we now automatically close the err
>> pipe if it was requested by the caller and it hasn't been closed
>> by the caller.  This simplifies anyone who wants to get a pipe to
>> the stderr stream for another process.
>
> IMHO, this is backwards.
>
> The .in, .out, .err members of struct child_process serve two different
> purposes:
>
> 1. Caller sets them to some fd > 0. This means:
>    "Here is a readable (.in) or writable (.out, .err) fd; use it."
>
> 2. Caller sets them to -1: This means:
>    "Create a pipe and give me the writable (.in) or readable (.out,
>    .err) end of it back."
>
> Notice that in a clean implementation:
>
> - case 1. would imply that the fd is "given away", i.e.
>   start_command/finish_command take ownership and close it;
>
> - case 2. would imply that the caller takes ownership of the returned
>   fd and has to close it.