I don't understand why the previous comment is talking about foo.q.  In what way would it ever be correct for foo.q to appear in "$?"?  foo.q is one of the targets and "$?" lists the out of date prerequisites.

Maybe the comment intended to use "foo.r" instead?

I understand what is being requested and it makes sense at some level.  However I can't reproduce the "desired" behavior in the current version of GNU Make HEAD.  I used this makefile:

MAKEFLAGS += -rR
.RECIPEPREFIX = >

xfoo: foo.p foo.q
xbar: bar.p bar.q

foo.p foo.q &: foo.r FORCE
> @echo '$$? = $?'
> touch foo.p foo.q

%.p %.q : %.r FORCE
> @echo '$$? = $?'
> touch $*.p $*.q

.PHONY: xfoo xbar FORCE

to combine both makefiles into a single makefile.

Whether or not we see foo.r (or bar.r) included in the output depends entirely on which target is touched before we start make and which is not.

For example if I use the original description and touch foo.p / bar.p first, then I see the "undesired" behavior for both explicit and pattern grouped targets:

$ rm -f foo.* bar.* ; touch foo.r bar.r; sleep 1; touch foo.p bar.p; make xfoo
$? = FORCE
touch foo.p foo.q

$ rm -f foo.* bar.* ; touch foo.r bar.r; sleep 1; touch foo.p bar.p; make xbar
$? = FORCE
touch bar.p bar.q

If on the other hand I touch foo.q / bar.q first, I see the "desired" behavior for both:

$ rm -f foo.* bar.* ; touch foo.r bar.r; sleep 1; touch foo.q bar.q; make xfoo
$? = foo.r FORCE
touch foo.p foo.q

$ rm -f foo.* bar.* ; touch foo.r bar.r; sleep 1; touch foo.q bar.q; make xbar
$? = bar.r FORCE
touch bar.p bar.q

Am I missing some important aspect of the original example that was posted?

As far as I can see commit fabb03eac412b5ea19f1a97be31dc8c6fa7fc047 is not related to this.  It does change the mtime of also-make targets which maybe is related somehow.

Dmitry's explanation of what is happening is correct.  Whether that's the right behavior or not, needs to be considered.  Also what would be involved with changing the behavior.

A user reported an issue here https://lists.gnu.org/archive/html/help-make/2024-08/msg00001.html.

Here is a copy of that email which contains a good description of the issue.

Hi.


I have two similar Makefiles.


[Makefile1]

.PHONY: all
all: foo.p foo.q

foo.p foo.q &: foo.r FORCE
        @echo \$$? = $?
        touch foo.p ; touch foo.q

.PHONY: FORCE



[Makefile2]

.PHONY: all
all: foo.p foo.q

%.p %.q : %.r FORCE
        @echo \$$? = $?
        touch foo.p ; touch foo.q

.PHONY: FORCE





The two Makefiles are the same, except for one line.
Makefile1 uses grouped targets.
Makefile2 uses a pattern rule with multiple targets.

My hope is that those two work in the same way.


[test Makefile1]

$ rm -f foo.*
$ touch foo.r
$ touch foo.p
$ make -f Makefile1
$? = foo.r FORCE
touch foo.p ; touch foo.q



[test Makefile2]

$ rm -f foo.*
$ touch foo.r
$ touch foo.p
$ make -f Makefile2
$? = FORCE
touch foo.p ; touch foo.q





The value of $? is different.

I just thought this was fixed by
commit fabb03eac412b5ea19f1a97be31dc8c6fa7fc047

In my opinion, the behavior of Makefile1 is preferred.
Is the behavior of Makefile2 expected?

i think, foo.r should not be in $? in this case.
make first considers foo.p. Make finds out that foo.p needs to be rebuilt due to FORCE. The recipe builds both foo.p and foo.q. Automatic variables are set per recipe execution. When this recipe runs, $? is set to FORCE, because FORCE is the prerequisite that caused the recipe to run.
foo.q is not even considered at all at this point.
Then make considers foo.q and finds out that foo.q is already built. Make runs no recipe specifically for foo.q and so no automatic variables are set for foo.q.