[OE-core] what is meaning of "SRC_URI_append_whatever +=" ??

[Robert P. J. Day]

On Wed, 21 Mar 2012, Robert P. J. Day wrote:

>
>   still perusing the very basics of oe-core and grepping madly, came
> across the following oddity:
>
> $ grep -r SRC_URI_append *
> ... snip ...
> bitbake/doc/manual/usermanual.xml:SRC_URI_append_1.0.7+ = "file://some_patch_which_the_new_versions_need.patch;patch=1"</screen></para>
> meta/recipes-support/gmp/gmp_5.0.4.bb:SRC_URI_append += "file://use-includedir.patch \
> meta/recipes-support/libcroco/libcroco_0.6.3.bb:SRC_URI_append = " file://croco.patch;apply=yes "
> ... snip ...
>
>   AIUI, there are two (common) variations for extending SRC_URI.  the
> straightforward unconditional way:
>
>   SRC_URI += ... blah blah ...
>
> or if you need to make it conditional, then there's
>
>   SRC_URI_append_thingy = "whatever"
>
> so what's with the latter two entries above?
>
> meta/recipes-support/gmp/gmp_5.0.4.bb:SRC_URI_append += "file://use-includedir.patch \
> meta/recipes-support/libcroco/libcroco_0.6.3.bb:SRC_URI_append = " file://croco.patch;apply=yes "
>
>   is there some subtlety i'm missing here?  why would one ever use
> either of:
>
>   SRC_URI_append += "..."               (looks redundant)
>   SRC_URI_append = "..."                (why not just SRC_URI +=?)
>
> can i just assume those are typoes?

  following up on my own post, i decided to scan the entire oe-core
tree:

$ grep -r "_append +=" *
meta/recipes-support/gmp/gmp_5.0.4.bb:SRC_URI_append += "file://use-includedir.patch \
meta/recipes-core/eglibc/eglibc-package.inc:FILES_${PN}-dev_append += "${bindir}/rpcgen ${libdir}/*_nonshared.a \
meta/recipes-core/eglibc/eglibc-package.inc:FILES_${PN}-staticdev_append += "${libdir}/*.a ${base_libdir}/*.a"
meta/recipes-graphics/xorg-lib/libxp_1.0.1.bb:CFLAGS_append += " -I ${S}/include/X11/XprintUtil -I ${S}/include/X11/extensions"
$

  and i thought i'd look for another pattern as well:

$ grep -r "_append_.*+=" *
meta/recipes-graphics/tslib/tslib_1.0.bb:SRC_URI_append_qemumips += " file://32bitBE-support.patch"
meta/recipes-graphics/tslib/tslib_1.0.bb:SRC_URI_append_qemuppc += " file://32bitBE-support.patch"
meta/recipes-sato/leafpad/leafpad_0.8.18.1.bb:SRC_URI_append_poky += " file://owl-menu.patch;apply=yes "
$

  of course, if all of the above is perfectly valid, i'm going to be
embarrassed.

rday

-- 

========================================================================
Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
========================================================================