[PATCH v4 06/15] update-alternatives: convert file renames to PACKAGE_PREPROCESS_FUNCS

["André Draszik" <git@andred.net>]

From: André Draszik <andre.draszik@jci.com>

At the moment, the update-alternatives file renaming is
happening right after copying into PKGD during packaging
time using an _append OVERRIDE to the copy function
perform_packagecopy().

This is not really readable and hard to maintain.

Additionally, this makes it impossible to e.g. populate
PACKAGES dynamically using do_split_packages() and still
do update-alternatives - update-alternatives file renaming
requires the PACKAGES variable to have been fully populated
to work correctly. On the other hand, do_split_packages()
can only execute after perform_packagecopy(), as it needs
PKGD populated; so it's impossible to insert
do_split_packages() early enough in a deterministic way in
this use-case.

As there doesn't seem to be a reason not to, convert
this to a proper function and use PACKAGE_PREPROCESS_FUNCS
instead - after all, that's what this is meant for.

No other classes or recipes in oe-core or meta-openembededd
seem to have a hard requirement on update-alterantives
executing before any other PACKAGE_PREPROCESS_FUNCS, so
this should be perfectly fine.

The only implication is that if compress_doc is inherited,
compressed man-page file names will end up being, e.g.
    eject.1.util-linux.gz
  or
    eject.1.gz.util-linux
based on the include of compress_doc.bbclass vs.
update-alternatives.bbclass order, but the symlink created
(alternative name) will always be correct.

This solves both problems:
* the code is easier to read / follow
* the above described use-case can be accomodated easily

[YOCTO #13058]

Signed-off-by: André Draszik <andre.draszik@jci.com>

---
v4: * unconditionally assign PACKAGE_PREPROCESS_FUNCS
---
 meta/classes/update-alternatives.bbclass | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/meta/classes/update-alternatives.bbclass b/meta/classes/update-alternatives.bbclass
index f1250f877b..f3c014a5fc 100644
--- a/meta/classes/update-alternatives.bbclass
+++ b/meta/classes/update-alternatives.bbclass
@@ -131,14 +131,13 @@ def gen_updatealternativesvars(d):
 populate_packages[vardeps] += "${UPDALTVARS} ${@gen_updatealternativesvars(d)}"
 
 # We need to do the rename after the image creation step, but before
-# the split and strip steps..  packagecopy seems to be the earliest reasonable
-# place.
-python perform_packagecopy_append () {
-    if update_alternatives_enabled(d):
-        apply_update_alternative_renames(d)
-}
+# the split and strip steps..  PACKAGE_PREPROCESS_FUNCS is the right
+# place for that.
+PACKAGE_PREPROCESS_FUNCS += "apply_update_alternative_renames"
+python apply_update_alternative_renames () {
+    if not update_alternatives_enabled(d):
+       return
 
-def apply_update_alternative_renames(d):
     # Check for deprecated usage...
     pn = d.getVar('BPN')
     if d.getVar('ALTERNATIVE_LINKS') != None:
@@ -204,6 +203,7 @@ def apply_update_alternative_renames(d):
                     os.unlink(src)
                 else:
                     bb.warn('%s: Unable to resolve dangling symlink: %s' % (pn, alt_target))
+}
 
 PACKAGESPLITFUNCS_prepend = "populate_packages_updatealternatives "
 
-- 
2.20.1