Change the error handling of the Wallet::ACL list() method to return the

empty list on errors and clear error() so that it can be used to
distinguish between an error and an empty ACL.

2 files changed, 9 insertions, 8 deletions

diff --git a/perl/Wallet/ACL.pm b/perl/Wallet/ACL.pm
index d6cc29c..4a9bd88 100644
--- a/perl/Wallet/ACL.pm
+++ b/perl/Wallet/ACL.pm
@@ -259,6 +259,7 @@ sub remove {
 # error.  Sets the internal error string on error.
 sub list {
     my ($self) = @_;
+    undef $self->{error};
     my @entries;
     eval {
         my $sql = 'select ae_scheme, ae_identifier from acl_entries where
@@ -272,7 +273,7 @@ sub list {
     };
     if ($@) {
         $self->error ("cannot retrieve ACL $self->{id}: $@");
-        return (undef);
+        return;
     } else {
         return @entries;
     }
@@ -285,7 +286,7 @@ sub list {
 sub show {
     my ($self) = @_;
     my @entries = $self->list;
-    if (@entries == 1 and not defined ($entries[0])) {
+    if (not @entries and $self->error) {
         return undef;
     }
     my $name = $self->name;
@@ -314,7 +315,7 @@ sub check {
         return undef;
     }
     my @entries = $self->list;
-    return undef if (@entries == 1 and not defined $entries[0]);
+    return undef if (not @entries and $self->error);
     my %verifier;
     $self->{check_errors} = [];
     for my $entry (@entries) {
@@ -481,10 +482,10 @@ C<alice@EXAMPLE.COM> and C<bob@EXAMPLE.COM>, list() would return:
 
     ([ 'krb5', 'alice@EXAMPLE.COM' ], [ 'krb5', 'bob@EXAMPLE.COM' ])
 
-Returns C<(undef)> (the list containing the single element undef) on
-failure, so that it can be distinguished from the empty list, which
-indicates the ACL contains no entries.  On failure, the caller should call
-error() to get the error message.
+Returns the empty list on failure.  To distinguish between this and the
+ACL containing no entries, the caller should call error().  error() is
+guaranteed to return the error message if there was an error and undef if
+there was no error.
 
 =item name()
 
diff --git a/perl/Wallet/Server.pm b/perl/Wallet/Server.pm
index 894a52e..b646eb0 100644
--- a/perl/Wallet/Server.pm
+++ b/perl/Wallet/Server.pm
@@ -555,7 +555,7 @@ sub acl_remove {
     }
     if ($acl->name eq 'ADMIN') {
         my @e = $acl->list;
-        if (@e == 1 and not defined ($e[0])) {
+        if (not @e and $acl->error) {
             $self->error ($acl->error);
             return undef;
         } elsif (@e == 1 && $e[0][0] eq $scheme && $e[0][1] eq $identifier) {