diff --git a/poky/meta/classes/metadata_scm.bbclass b/poky/meta/classes/metadata_scm.bbclass
index 2608a7e..47cb969 100644
--- a/poky/meta/classes/metadata_scm.bbclass
+++ b/poky/meta/classes/metadata_scm.bbclass
@@ -1,8 +1,3 @@
-METADATA_BRANCH ?= "${@base_detect_branch(d)}"
-METADATA_BRANCH[vardepvalue] = "${METADATA_BRANCH}"
-METADATA_REVISION ?= "${@base_detect_revision(d)}"
-METADATA_REVISION[vardepvalue] = "${METADATA_REVISION}"
-
 def base_detect_revision(d):
     path = base_get_scmbasepath(d)
     return base_get_metadata_git_revision(path, d)
@@ -42,3 +37,8 @@
     except bb.process.ExecutionError:
         rev = '<unknown>'
     return rev.strip()
+
+METADATA_BRANCH := "${@base_detect_branch(d)}"
+METADATA_BRANCH[vardepvalue] = "${METADATA_BRANCH}"
+METADATA_REVISION := "${@base_detect_revision(d)}"
+METADATA_REVISION[vardepvalue] = "${METADATA_REVISION}"