make printvars: avoid invalid calls when arguments are missing

during "make printvars > compare" the following error occurs -
reproducible after any "make *_defconfig":

/bin/bash: support/dependencies/check-host-.sh: no such file or directory
/bin/bash: -c: line 0: syntax error: ')' unexpected
/bin/bash: -c: line 0: `set -e; TMP="$(mktemp)"; if () >/dev/null 2>&1; then echo ""; else echo ""; fi;

which is 2 errors, resulting from $(1) arguments being empty, but
called anyway. So this simply skips parts when otherwise we would exit
when wrong scripts are tried be executed.

When comparing the outputs, this _adds_ "host-tar host-xz" to all packages'
*_DEPENDENCIES where until now only "host-lzip" is listed.

Signed-off-by: Martin Kepplinger <martin.kepplinger@ginzinger.com>
---
Hi,

This has been reported by me and others before and this patch might
as well _not_ be the real fix :) I guess $(1) should just never become
empty in the first place, right?

Anyways, I let you decide whether this fixes things (add host-tar dependency
for every package) and how much sense this makes.

Maybe you know what's going on.

thanks,

                                martin



 package/Makefile.in                  | 2 ++
 support/dependencies/dependencies.mk | 2 ++
 2 files changed, 4 insertions(+)

Hello Martin,

On Sat, 23 Feb 2019 17:11:08 +0100
Martin Kepplinger <martin.kepplinger@ginzinger.com> wrote:

> diff --git a/package/Makefile.in b/package/Makefile.in
> index dc818a2c18..f4f3864e8d 100644
> --- a/package/Makefile.in
> +++ b/package/Makefile.in
> @@ -232,6 +232,7 @@ HOST_LDFLAGS  += -L$(HOST_DIR)/lib -Wl,-rpath,$(HOST_DIR)/lib
>  # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
>  # Exit code chooses option. "$$TMP" is can be used as temporary file and
>  # is automatically cleaned up.
> +ifneq ($(1),)

$(1) only makes sense inside the macro itself. Outside the macro $(1)
does not make sense at all, and will always be empty I believe. Are you
sure your patch is working, and does not break the build ?

Indeed, I believe the two macros you enclose in ifneq tests will in
fact no longer be defined.

Thomas

(sorry for the horrible email format)

my patch does not break the build. In fact, it *adds* host-tar to my build (for the first time
ever it seems because it just downloaded).

My impression is that what's *below* the $(1) expression in support/dependencies/dependencies.mk
didn't get defined... (host-tar).

I've built successfully. Still, the kind of change doesn't look very beautiful.

Maybe there someone who sees the mistake at first sight :)

thanks

                                   martin



Martin Kepplinger | Entwicklung Software

GINZINGER ELECTRONIC SYSTEMS GMBH

Tel.: +43 7723 5422 157
Mail: martin.kepplinger@ginzinger.com
Web: www.ginzinger.com

Martin, All,

On 2019-02-25 07:09 +0000, Kepplinger Martin spake thusly:
> (sorry for the horrible email format)
> 
> my patch does not break the build. In fact, it *adds* host-tar to my build (for the first time
> ever it seems because it just downloaded).
> 
> My impression is that what's *below* the $(1) expression in support/dependencies/dependencies.mk
> didn't get defined... (host-tar).
> 
> I've built successfully. Still, the kind of change doesn't look very beautiful.
> 
> Maybe there someone who sees the mistake at first sight :)

I agree with Thomas: the patch as it is, is not correct. As Thomas
explained, at the exact moment you evaluate $(1) to test if it is empty,
you are outside the macro. However, $(1) only ever makes sense in a
macro, because it is the first parameter of a macro.

So, it means the test will aways fail: $(1) is always empty outside a
macro, so   ifneq ($(1),)   is always false.

As a consequnce, as Thomas said, the two macros enclosed in the ifneq
will never be defined.

Instead, what you want is to do the test inside the macro, like:

    define suitable-host-package
    ifneq ($(1),)
    $(shell support/dependencies/check-host-$(1).sh $(2))
    endif
    endef

Or:

    try-run = $(if $(1), ...
        ...
        )

And so on...

I've marked the patch as "Changes Requested" in patchwork while waiting
for the next iteration. Thanks! :-)

Regards,
Yann E. MORIN.

> On Sat, 23 Feb 2019 17:11:08 +0100
> Martin Kepplinger <martin.kepplinger@ginzinger.com> wrote:
> 
> > diff --git a/package/Makefile.in b/package/Makefile.in
> > index dc818a2c18..f4f3864e8d 100644
> > --- a/package/Makefile.in
> > +++ b/package/Makefile.in
> > @@ -232,6 +232,7 @@ HOST_LDFLAGS  += -L$(HOST_DIR)/lib -Wl,-rpath,$(HOST_DIR)/lib
> >  # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
> >  # Exit code chooses option. "$$TMP" is can be used as temporary file and
> >  # is automatically cleaned up.
> > +ifneq ($(1),)
> 
> $(1) only makes sense inside the macro itself. Outside the macro $(1)
> does not make sense at all, and will always be empty I believe. Are you
> sure your patch is working, and does not break the build ?
> 
> Indeed, I believe the two macros you enclose in ifneq tests will in
> fact no longer be defined.
> 
> Thomas
> --
> Thomas Petazzoni, CTO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
> 
> 
> 
> ________________________________________
> 
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> 4952 Weng im Innkreis
> www.ginzinger.com
> 
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> UID-Nr.: ATU66521089
> 
> 
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