bitbake: data_smart: Ensure variable flags are accounted for in config data hash

Currently if the flags set against a variable in the base data store
change, it doesn't automatically trigger a reparse when it really
should. For example with the blacklist class setting:

PNBLACKLIST[qemu] = "bar"
PNBLACKLIST[bash] = "foo"

will not trigger a reparse if only one entry is changed and a
blacklisted recipe can still be built.

I did consider using BB_SIGNATURE_EXCLUDE_FLAGS in here however it
doesn't make sense, we want to trigger a reparse when any of the
flags change too (which is different to the sstate signatures which
we wouldn't want to change in those cases).

[YOCTO #4627]

(Bitbake rev: ed74ea50043f6feb698c891e571feda2b9f8513d)

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

bitbake/lib/bb/data_smart.py

@@ -738,6 +738,12 @@ class DataSmart(MutableMapping):
             value = d.getVar(key, False) or ""
             data.update({key:value})
 
+            varflags = d.getVarFlags(key)
+            if not varflags:
+                continue
+            for f in varflags:
+                data.update({'%s[%s]' % (key, f):varflags[f]})
+
         for key in ["__BBTASKS", "__BBANONFUNCS", "__BBHANDLERS"]:
             bb_list = d.getVar(key, False) or []
             bb_list.sort()