Re: make calling script calling make results in read jobs pipe: Bad file descriptor. Stop.

[Paul Smith]

On Thu, 2021-03-04 at 14:12 -0500, Martin d'Anjou wrote:
> Thanks Paul, but I am confused by this paragraph:
> 
> >However, make ALWAYS sends along the MAKEFLAGS variable to all commands
> >it runs, whether they are sub-makes or not.  And, there is a bug (filed
> >in Savannah) that even when make determines that the process is not a
> >sub-make, it will still send along the jobserver information in
> >MAKEFLAGS.
> 
> The confusing parts to me: "make ALWAYS sends along the MAKEFLAGS"
> and "it will still send along the jobserver information in
> MAKEFLAGS".
> 
> If make already always sends MAKEFLAGS, why say that the bug fix
> proposes to also always send MAKEFLAGS. I am not getting it... it's
> already doing it.

I probably just wasn't clear.

Today, all commands make invokes receive MAKEFLAGS in their environment
and the value of that variable is always the same, regardless of
whether the jobserver file descriptors were closed or not.

For example, it might be this:

    MAKEFLAGS=-j10 --jobserver-auth=3,4

What I'm saying is that we want to make a change where if make invokes
a sub-make and leaves the jobserver pipe open, it will send the above
value of MAKEFLAGS to the command.

But, if make invokes a non-sub-make process and closes the jobserver
pipe (so that file descritors 3 and 4 are no longer valid for the
jobserver), we will change make to send a MAKEFLAGS value like:

    MAKEFLAGS=-j10 --jobserver-auth=-

or something instead, so that any subprocess make invocations that
inherit this MAKEFLAGS will know that they shouldn't try to use the
jobserver and won't try to use descriptors 3 and 4 as the jobserver
pipe.