bitbake: BBhandler/data: Fix __inherit_cache duplication

The inherits cache contains duplicate entries, some with the full patch, some
just starting classes/xxx. This is a waste of parse time and potentially
error prone. This patch fixes various pieces of code so the absolute paths are
always preferred and work correctly. The inherits_class function did not work
with full paths so the patch fixes this.

(Bitbake rev: f3a71e509af196391ec126d079cf1bd178e62ad5)

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

bitbake/lib/bb/parse/parse_py/BBHandler.py

@@ -74,6 +74,13 @@ def inherit(files, fn, lineno, d):
         if not os.path.isabs(file) and not file.endswith(".bbclass"):
             file = os.path.join('classes', '%s.bbclass' % file)
 
+        if not os.path.isabs(file):
+            dname = os.path.dirname(fn)
+            bbpath = "%s:%s" % (dname, d.getVar("BBPATH", True))
+            abs_fn = bb.utils.which(bbpath, file)
+            if abs_fn:
+                file = abs_fn
+
         if not file in __inherit_cache:
             logger.log(logging.DEBUG -1, "BB %s:%d: inheriting %s", fn, lineno, file)
             __inherit_cache.append( file )