'make -n TARGET' is broken

[mkoeppe]

make -n sagelib should only print, not run, commands.

Likewise make -q sagelib should not run commands. As this is used in build/make/install with output suppressed, this sometimes leads to sage -b silently doing the rebuild and then reporting "Nothing to do".

Broken for normal packages already in Sage 9.0; broken for script packages by #32759 by using + in build/make/Makefile.in *-*-no-deps rules for script packages.

That + appears there is motivated by intended jobserver behavior; but unfortunately it also influences -n, -q, -t handling.

Depends on #33130

CC: @orlitzky

Component: build

Branch: u/mkoeppe/_make__n_target__is_broken

Issue created by migration from https://trac.sagemath.org/ticket/33125

[mkoeppe]

comment:5

A solution is to do a bit of MAKEFLAGS parsing - see e.g. https://stackoverflow.com/questions/19521438/how-to-access-make-options-in-makefile

[orlitzky]

comment:6

Isn't this just because invoking build/make/install interrupts the $MAKE and $MAKEFLAGS magic that normally gets applied to sub-makes?

For example, this fixes make -n sagelib for me:

diff --git a/Makefile b/Makefile
index 444e4f9e4a..9505152830 100644
--- a/Makefile
+++ b/Makefile
@@ -37,7 +37,7 @@ sageruntime: base-toolchain
 	@if [ -x relocate-once.py ]; then ./relocate-once.py; fi
 	$(MAKE) build/make/Makefile --stop
 	+build/bin/sage-logger \
-		"cd build/make && ./install '$@'" logs/install.log
+		"cd build/make && MAKE=\"$(MAKE)\" MAKEFLAGS=\"$(MAKEFLAGS)\" ./install '$@'" logs/install.log
 
 # CONFIG_FILES lists all files that appear in AC_CONFIG_FILES in configure.ac;
 # except for build/make/Makefile-auto, which is unused by the build system

[mkoeppe]

comment:7

Did you test this on top of #32759?

[mkoeppe]

comment:8

No, the problem is that we want to pass jobserver flags to something that is not make (and therefore does not handle -n etc.), namely the spkg-install script.

[orlitzky]

comment:9

Replying to @mkoeppe:

Did you test this on top of #32759?

No, but the problem with make -n sagelib already exists in beta9.

[mkoeppe]

comment:10

OK, you are right, there is broader breakage regarding -n etc. that has been around for a long time.

But there's a more specific problem (of blocker quality) caused by #32759. I've opened #33130 for it.

Let's address the broader problem in Sage 9.6.

[mkoeppe]

Changed dependencies from #32759 to #33130

[mkoeppe]

Branch: u/mkoeppe/_make__n_target__is_broken