[Buildroot] [PATCH 1 of 7 v2] infra: consistently use double dollar signs inside inner-xxx-targets

[Arnout Vandecappelle <arnout@mind.be>]

On 21/05/14 15:14, Thomas De Schampheleire wrote:
> Hi Arnout,
> 
> On Tue, May 13, 2014 at 11:25 AM, Arnout Vandecappelle <arnout@mind.be> wrote:
> [..]
>>>
>>> @@ -548,7 +550,7 @@ endif
>>>  $$($(2)_TARGET_RSYNC_SOURCE):                SRCDIR=$$($(2)_OVERRIDE_SRCDIR)
>>>  $$($(2)_TARGET_RSYNC_SOURCE):                PKG=$(2)
>>>  $$($(2)_TARGET_PATCH):                       PKG=$(2)
>>> -$$($(2)_TARGET_PATCH):                       RAWNAME=$(patsubst host-%,%,$(1))
>>> +$$($(2)_TARGET_PATCH):                       RAWNAME=$$(patsubst host-%,%,$(1))
>>>  $$($(2)_TARGET_PATCH):                       PKGDIR=$(pkgdir)
>>>  $$($(2)_TARGET_EXTRACT):             PKG=$(2)
>>>  $$($(2)_TARGET_SOURCE):                      PKG=$(2)
>>> @@ -559,9 +561,9 @@ endif
>>>  # kernel case, the bootloaders case, and the normal packages case.
>>>  ifeq ($(1),linux)
>>>  $(2)_KCONFIG_VAR = BR2_LINUX_KERNEL
>>> -else ifneq ($(filter boot/%,$(pkgdir)),)
>>> +else ifneq ($$(filter boot/%,$(pkgdir)),)
>>
>>  $$(pkgdir) works fine here. Also, it gets evaluated only once anyway, so
>> there's no speedup from using a single $.
>>
> 
> While creating v3 of this patch and retesting, I bumped into a nasty
> situation regarding pkgdir: the foo-patch rule is executed with the
> variable PKGDIR=$(pkgdir) which I changed to PKGDIR=$$(pkgdir).
> However, in that case, the foo-patch rule, which is outside
> inner-targets, gets executed with the literal $(pkgdir) as PKGDIR,
> which is evaluated to docs/manual (the directory of the last makefile
> parsed).
> As a result, package patching does not occur.
> 
> There are two solutions:
> - do not double the $$ here, so keep the originial PKGDIR=$(pkgdir)
> - use :=, so PKGDIR:=$(pkgdir)
> 
> I feel that if we take the first alternative, we should consistently
> use $(pkgdir) like that as it is less error-prone to have it as a
> general exception, than as an
> exception-only-if-you-pass-it-to-non-inner-rules.
> All of this is because the pkgdir variable is rather tricky.

 Okay, I agree: first option is the best one, and then we should use it
everywhere for pkgdir. Also, for pkgdir, not delaying expansion (i.e. single-$)
can never be incorrect. Same goes for pkgname, obviously. Which matches your
earlier observation that pkgname is special.

 Can you add an explanation about this in the leading comment of
inner-generic-package?


 Regards,
 Arnout

> 
> Thanks,
> Thomas
> 


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
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