Re: Regression on Cygwin: Problems with parallel make in 4.4

[Paul Smith]

On Tue, 2023-02-21 at 08:35 -0500, Ken Brown wrote:
> On 2/21/2023 3:54 AM, Ken Brown wrote:
> > On 2/21/2023 12:27 AM, Paul Smith wrote:
> > > Just to note, I do run the regression test suite with the
> > > equivalent of "jobserver-style=pipe" (basically I force the
> > > configure to believe that the system doesn't support mkfifo() so
> > > it falls back to "pipe" mode).
> 
> Somehow the test suite isn't catching this problem, at least on
> Cygwin.

Understood.  I'm just saying it's not the case that there is no testing
at all with "pipe", anymore.  Agreed that the regression tests are not
completely sufficient to find all problems.

> make[5]: not recursive -2,-2
> make[5]: warning: jobserver unavailable: using -j1.  Add '+' to
> parent make rule.

Perfect, thanks.  That probably means the message is the result of an
explicit change we made to lock down the pipe mode, rather than some
unanticipated modification.  I'll look at the makefile you provided to
see if I can figure it out.  Maybe the changes we made need to be
adjusted.

For more info, see this entry in the NEWS file:

* When the pipe-based jobserver is enabled and GNU Make decides it is invoking
  a non-make sub-process and closes the jobserver pipes, it will now add a new
  option to the MAKEFLAGS environment variable that disables the jobserver.
  This prevents sub-processes that invoke make from accidentally using other
  open file descriptors as jobserver pipes.  For more information see
  https://savannah.gnu.org/bugs/?57242 and https://savannah.gnu.org/bugs/?62397

The "option that disables the jobserver" is where the -2,-2 comes from.