[Buildroot] [PATCH] toolchain package: set version as 'virtual' instead of 'undefined'

[Arnout Vandecappelle <arnout@mind.be>]

On 08/05/14 09:04, Thomas De Schampheleire wrote:
> Hi,
> 
> On Wed, May 7, 2014 at 9:37 PM, Thomas De Schampheleire
> <patrickdepinguin@gmail.com> wrote:
> [..]
> 
>>>> I tried using virtual-package in toolchain/toolchain/toolchain.mk, but TOOLCHAIN_VERSION becomes empty, while HOST_TOOLCHAIN_VERSION is virtual.
> 
> [..]
> 
> Some more feedback: I stepped away from toolchain and added a simple
> test package 'mytest' as below.
> I added a debug target 'bar' and some variable assignment in pkg-generic.mk.
> 
> 
> diff --git a/package/mytest/mytest.mk b/package/mytest/mytest.mk
> new file mode 100644
> --- /dev/null
> +++ b/package/mytest/mytest.mk
> @@ -0,0 +1,10 @@
> +
> +$(eval $(virtual-package))
> +
> +bar:
> +       @echo MYTEST_VERSION = $(MYTEST_VERSION)
> +       @echo HOST_MYTEST_VERSION = $(HOST_MYTEST_VERSION)
> +       @echo MYTEST_X = $(MYTEST_X)
> +       @echo MYTEST_Y = $(MYTEST_Y)
> +       @echo HOST_MYTEST_X = $(HOST_MYTEST_X)
> +       @echo HOST_MYTEST_Y = $(HOST_MYTEST_Y)
> diff --git a/package/pkg-generic.mk b/package/pkg-generic.mk
> --- a/package/pkg-generic.mk
> +++ b/package/pkg-generic.mk
> @@ -262,6 +262,12 @@ define inner-generic-package
>  # sanitize the package version that is used in paths, directory and file names.
>  # Forward slashes may appear in the package's version when pointing to a
>  # version control system branch or tag, for example remotes/origin/1_10_stable.
> +
> +ifdef $(2)_VERSION
> +  $(2)_X := $(subst /,_,$($(2)_VERSION))
> +  $(2)_Y := $(subst /,_,$$($(2)_VERSION))
> +endif
> +
>  ifndef $(2)_VERSION
>   ifdef $(3)_VERSION
>    $(2)_DL_VERSION = $($(3)_VERSION)
> 
> 
> In pkg-generic.mk, the _VERSION variables are defined, and there is a
> subst() statement to replace / with _.
> My conclusion is that the line with the subst statement does not work
> when _VERSION is set like in virtual-package.
> 
> The output of 'make bar' is:
> MYTEST_VERSION =
> HOST_MYTEST_VERSION = virtual
> MYTEST_X =
> MYTEST_Y = virtual
> HOST_MYTEST_X =
> HOST_MYTEST_Y =
> 
> X is using the standard subst line as pkg-generic is using, while Y
> adds an extra dollar sign.
> When the version is set directly, as in MYTEST_VERSION = bla, then X
> seems to be correct. This is the way buildroot works today. However,
> when the version is set indirectly from an inner-xxx-package, like
> $(3)_VERSION, then X no longer works but Y does. However, adding an
> extra dollar by default doesn't work for the normal packages.
> 
> So how to proceed? Any experts in the inner-xxx-package and make internals?
> Arnout, ThomasP, Yann?

 Let me see if I can analyse it.

$(eval $(virtual-package))

recursively expands to:

$(eval
...
MYTEST_VERSION = virtual
HOST_MYTEST_VERSION = virtual
...

# expansion of inner-generic-package
# ** At this point MYTEST_VERSION is not set yet! **
ifdef MYTEST_VERSION
  MYTEST_X :=
  MYTEST_Y := $$(MYTEST_VERSION)
endif

ifndef MYTEST_VERSION
 ifdef MYTEST_VERSION
  MYTEST_DL_VERSION =
  MYTEST_VERSION =
 else
  MYTEST_VERSION = undefined
  MYTEST_DL_VERSION = undefined
 endif
else
  MYTEST_DL_VERSION =
  MYTEST_VERSION =
endif
...
) #eval



 I repeat my earlier statement: within a function that is supposed to be
eval'ed, *everything* should be $$'ed except the function arguments and except
some very specific cases.


 Regards,
 Arnout


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
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