From ea65ed57afcaef722da75a6f317db4da370e7f98 Mon Sep 17 00:00:00 2001
From: Bill Fenner <>
Date: Mon, 8 Oct 2007 22:30:30 +0000
Subject: [PATCH] Teach Baystack's e_index() that Entity's e_index() is
 implemented based on e_descr() - otherwise, Entity's e_index() will always
 return a mapping even if the device doesn't implement the ENTITY-MIB.

---
 Info/Layer2/Baystack.pm | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/Info/Layer2/Baystack.pm b/Info/Layer2/Baystack.pm
index 716d68d3..8810ee4a 100644
--- a/Info/Layer2/Baystack.pm
+++ b/Info/Layer2/Baystack.pm
@@ -347,7 +347,17 @@ sub e_index {
     my $stack   = shift;
     my $partial = shift;
 
-    return $stack->SUPER::e_index($partial) || $stack->ns_e_index($partial);
+    # This has intimate knowledge of the implementation of e_index.
+    # e_index is implemented in terms of e_descr, so unlike the other
+    # functions below we can't just
+    # return $stack->SUPER::e_index($partial) || $stack->ns_e_index($partial);
+    # since it will call *our* e_descr.  So we only call e_index if
+    # SUPER::e_descr works.
+    if ($stack->SUPER::e_descr($partial)) {
+	return $stack->SUPER::e_index($partial);
+    } else {
+	return $stack->ns_e_index($partial);
+    }
 }
 
 sub e_class {
@@ -607,7 +617,9 @@ L<SNMP::Info::NortelStack/"TABLE METHODS"> for details on ns_e_* methods.
 
 =item $baystack->e_index() 
 
-If the device doesn't support B<entPhysicalIndex>, this will try ns_e_index().
+If the device doesn't support B<entPhysicalDescr>, this will try ns_e_index().
+Note that this is based on B<entPhysicalDescr> due to implementation
+details of SNMP::Info::Entity::e_index().
 
 =item $baystack->e_class()