commit daa5d1e66791a155dc74b220f16422ba206b8788
Author: John Dennis <jdennis@redhat.com>
Date:   Tue Jun 13 09:34:36 2017 -0400

    If no IdP's are defined explicitly log that fact
    
    Sometimes configuration errors are made and a location does have any
    IdP's defined for it. Previosly the error message in this case was:
    
    "Error adding IdP to lasso server object. Please verify the following
    configuration directives: MellonIdPMetadataFile and
    MellonIdPPublicKeyFile."
    
    But this message is misleading, it suggests an attempt was made to add
    the IdP but somehow it failed, this will often cause folks to try to
    determine what is wrong with the IdP metadata file, which may in fact
    be defined in the mellon config but because of location inheritance is
    not being included in the per directory config.
    
    It would be much more helpful to indicate no IdP's were defined for
    this config location which is clearly a different problem than
    suggesting an attempt was made to add an IdP but it failed.
    
    Signed-off-by: John Dennis <jdennis@redhat.com>

diff --git a/auth_mellon_handler.c b/auth_mellon_handler.c
index 44a5ee9..2004752 100644
--- a/auth_mellon_handler.c
+++ b/auth_mellon_handler.c
@@ -242,6 +242,12 @@ static guint am_server_add_providers(am_dir_cfg_rec *cfg, request_rec *r)
         idp_public_key_file = NULL;
 #endif /* ! HAVE_lasso_server_load_metadata */
 
+    if (cfg->idp_metadata->nelts == 0) {
+            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
+                          "Error, URI \"%s\" has no IdP's defined", r->uri);
+            return 0;
+    }
+
     for (index = 0; index < cfg->idp_metadata->nelts; index++) {
         const am_metadata_t *idp_metadata;
         int error;