Pair emake -j1 with --shuffle=none

[Flowdalic]

Thanks to trofi, GNU make 4.4 gained the --shuffle option to detect unsound Makefiles [1]. Gentoo's tinderboxes use --shuffle to find and report such issues. However, they also would report broken Makefiles where the ebuild author knew that the Makefile is broken, and hence added -j1 to the make invocation [2]..

To stop Tinderboxes from creating noise by reporting known issues, this change devmanual to suggest pairing -j1 with --shuffle=none for the compile case. Devmanual also suggest to consider -j1 for resource intensive testsuites, but this does not require --shuffle.

1: https://trofi.github.io/posts/249-an-update-on-make-shuffle.html
2: https://bugs.gentoo.org/947303#c10
Signed-off-by: Florian Schmaus [email protected]

[ulm]

This looks like an option that has a special and very narrow purpose.

Maybe this should be fixed on the tinderbox side instead?

[Flowdalic]

Maybe this should be fixed on the tinderbox side instead?

I would have hoped this as well and this was briefly discussed in #-dev and #-tinderbox, but I guess its not that easy, even though probably possible. Tinderboxes would need to hook into the make invocation and determine if -j1 is active.

[ulm]

Maybe this should be fixed on the tinderbox side instead?

I would have hoped this as well and this was briefly discussed in #-dev and #-tinderbox, but I guess its not that easy, even though probably possible. Tinderboxes would need to hook into the make invocation and determine if -j1 is active.

Still sounds better to me than modifying many ebuilds. Also, what about make variants that don't support the option? https://trofi.github.io/posts/249-an-update-on-make-shuffle.html mentions passing the option via the GNUMAKEFLAGS variable rather than the command line. Would something like GNUMAKEFLAGS="${GNUMAKEFLAGS} --shuffle=none" emake -j1 work?