user: disallow older EAPIs

BUG=b:187790077
TEST=CQ passes

Change-Id: Iabe0c4ef37ce63d48a9e832543261191b934b1c7
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/eclass-overlay/+/4111199
Reviewed-by: Sloan Johnson <sloanjohnson@google.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/eclass/user.eclass b/eclass/user.eclass
index 5ded7e3..861bb05 100644
--- a/eclass/user.eclass
+++ b/eclass/user.eclass
@@ -11,6 +11,11 @@
 # manages the database in ${ROOT}, changing the sysroot database
 # only when the caller creates the user/group during setup.
 
+case ${EAPI} in
+5|6|7|8) ;;
+*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
+esac
+
 # Before we manipulate users at all, we want to make sure that
 # passwd/group/shadow is initialized in the first place. That's
 # what baselayout does.