On 04/12/2018 12:00, Edward Welbourne wrote: > pacalet (4 December 2018 08:38) wrote: >> Not sure it is a bug but I think it deserves some attention. Here is an >> MCVE: >> >> ```make >> .PHONY: all clean >> >> all:; >> >> include a.mk >> >> a.mk: b >> >> b: >> @touch $@ >> @printf '$$(info a.mk included)' > a.mk >> >> clean: >> @rm -f a.mk b >> ``` >> >> First make invocation: >> >> ```bash >> $ make >> make: Nothing to be done for 'all'. >> ``` >> >> Second make invocation: >> >> ```bash >> make >> a.mk included >> make: Nothing to be done for 'all'. >> ``` >> >> So we are in a situation where: >> >> 1. a makefile is included with the `include` directive (no `-include`), >> 2. the included makefile is not found, >> 3. make finds no rule to produce it and decides not to include it, > > Doesn't it ? It depends on b, albeit with an empty rule for what to do > when b changes. So exercising b's rule and then a.mk's empty rule is > what I expect it to do. Indeed, omitting your @ from the start of b's > rule commands, I see b is built on the first pass and a.mk is created. > I'm then puzzled that the first run doesn't report that it included > a.mk, though ...
Well, to be more accurate, make finds no rule with target `a.mk` *and with a recipe*. It finds a rule but as it has no recipe make considers that `a.mk` cannot be created. If you try `make -d` you'll see that it tries all implicit rules for `a.mk` before giving up. > >> 4. make executes a recipe for a prerequisite of the included makefile >> that incidentally also produces the included makefile, >> 5. as the included makefile is finally found make does not fail... but >> it does not read the included makefile. >> >> This could be considered as contradictory with the documentation: > >>> After all makefiles have been checked, if any have >>> actually been changed, make starts with a clean >>> slate and reads all the makefiles over again. > >> Shouldn't make either fail or include? > > Well, it shouldn't fail, since it does create a.mk; however, when I > change the redirect > a.mk on b's second command to > b.mk, it still > succeeds, despite there being no a.mk; presumably this is because a.mk > has a rule, that succeeds, so it's happy; but I still don't see why make > doesn't get upset about the unsatisfied include. > > Let's see what Paul says when the other side of the Atlantic wakes up, Yep. Note that I would not be shocked if make was failing in this situation... if the manual was clear about this. Something like "if a makefile is included it must be the target of a rule *with a recipe* and executing this recipe *must* produce the included makefile". Renaud. > > Eddy. > -- Renaud Pacalet Télécom ParisTech - LabSoC, c/o EURECOM Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE Tel : +33 (0) 4 9300 8402 Web : http://www.telecom-paristech.fr/
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