create-spdx-3.0/populate_sdk_base: Add SDK_CLASSES inherit mechanism to fix tarball SPDX manifests

Currently, "tarball" sdk based recipes don't generate SPDX manifests as they
don't include the rootfs generation classes. Split the SPDX 3.0 image class into
two so the SDK components can be included where needed.

To do this, introduce an SDK_CLASSES variable similar to IMAGE_CLASSES which
the SDK code can use.

Migrate testsdk usage to this.

Also move the image/sdk spdx classes to classes-recipe rather than the general classes
directory since they'd never be included on a global level.

For buildtools-tarball, it has its own testsdk functions so disable the class there as
a deferred inherit would overwrite it.

(From OE-Core rev: 95660951a09e2a3fe63eb1017ad8f1d7fc9cd503)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

(cherry picked from commit 662396533177b72cc1d83e95841b27f7e42dcb20)

Eliminate spdx-3.0 items, not applicable to Scarthgap.

Signed-off-by: Mark Hatle <mark.hatle@kernel.crashing.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

meta/classes-recipe/populate_sdk_base.bbclass

@@ -4,6 +4,9 @@
 # SPDX-License-Identifier: MIT
 #
 
+SDK_CLASSES += "${@bb.utils.contains("IMAGE_CLASSES", "testimage", "testsdk", "", d)}"
+inherit_defer ${SDK_CLASSES}
+
 PACKAGES = ""
 
 # This exists as an optimization for SPDX processing to only run in image and

meta/classes-recipe/testimage.bbclass

@@ -483,5 +483,3 @@ python () {
     if oe.types.boolean(d.getVar("TESTIMAGE_AUTO") or "False"):
         bb.build.addtask("testimage", "do_build", "do_image_complete", d)
 }
-
-inherit testsdk

meta/recipes-core/meta/buildtools-tarball.bb

@@ -112,6 +112,9 @@ INHIBIT_DEFAULT_DEPS = "1"
 # Directory in testsdk that contains testcases
 TESTSDK_CASES = "buildtools-cases"
 
+# We have our own code, avoid deferred inherit
+SDK_CLASSES:remove = "testsdk"
+
 python do_testsdk() {
     import oeqa.sdk.testsdk
     testsdk = oeqa.sdk.testsdk.TestSDK()