From afa6533f4308092ad7cda89a80b7886cceef9f20 Mon Sep 17 00:00:00 2001
From: Daniel Nichter <daniel@percona.com>
Date: Wed, 27 Mar 2013 11:12:38 -0600
Subject: [PATCH] Fix and test resource_diff().

---
 bin/pt-agent                |  9 +++++++--
 lib/Percona/WebAPI/Util.pm  |  9 +++++++--
 t/lib/Percona/WebAPI/Util.t | 13 ++++++++++++-
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/bin/pt-agent b/bin/pt-agent
index ce2c057a..89ce5d4a 100755
--- a/bin/pt-agent
+++ b/bin/pt-agent
@@ -1466,6 +1466,7 @@ no Lmo;
 {
 package Percona::WebAPI::Util;
 
+use JSON;
 use Digest::MD5 qw(md5_hex);
 
 use Percona::WebAPI::Representation; 
@@ -1478,8 +1479,12 @@ sub resource_diff {
    my ($x, $y) = @_;
    return 0 if !$x && !$y;
    return 1 if ($x && !$y) || (!$x && $y);
-   return md5_hex(Percona::WebAPI::Representation::as_json($x))
-       ne md5_hex(Percona::WebAPI::Representation::as_json($y));
+   my $json = JSON->new->canonical([1]);  # avoid hash key sort diffs
+   my $x_hex = md5_hex(
+      Percona::WebAPI::Representation::as_json($x, json => $json));
+   my $y_hex = md5_hex(
+      Percona::WebAPI::Representation::as_json($y, json => $json));
+   return $x_hex eq $y_hex ? 0 : 1;
 }
 
 1;
diff --git a/lib/Percona/WebAPI/Util.pm b/lib/Percona/WebAPI/Util.pm
index 2522a462..5eff0f91 100644
--- a/lib/Percona/WebAPI/Util.pm
+++ b/lib/Percona/WebAPI/Util.pm
@@ -20,6 +20,7 @@
 {
 package Percona::WebAPI::Util;
 
+use JSON;
 use Digest::MD5 qw(md5_hex);
 
 use Percona::WebAPI::Representation; 
@@ -32,8 +33,12 @@ sub resource_diff {
    my ($x, $y) = @_;
    return 0 if !$x && !$y;
    return 1 if ($x && !$y) || (!$x && $y);
-   return md5_hex(Percona::WebAPI::Representation::as_json($x))
-       ne md5_hex(Percona::WebAPI::Representation::as_json($y));
+   my $json = JSON->new->canonical([1]);  # avoid hash key sort diffs
+   my $x_hex = md5_hex(
+      Percona::WebAPI::Representation::as_json($x, json => $json));
+   my $y_hex = md5_hex(
+      Percona::WebAPI::Representation::as_json($y, json => $json));
+   return $x_hex eq $y_hex ? 0 : 1;
 }
 
 1;
diff --git a/t/lib/Percona/WebAPI/Util.t b/t/lib/Percona/WebAPI/Util.t
index bc7a754a..c585016c 100644
--- a/t/lib/Percona/WebAPI/Util.t
+++ b/t/lib/Percona/WebAPI/Util.t
@@ -45,7 +45,18 @@ $y->options->{spool} = '/var/lib/spool';
 is(
    resource_diff($x, $y),
    1,
-   "Diff"
+   "Big diff in 1 attrib"
+);
+
+# Restore this...
+$y->options->{spool} = '/var/spool';
+# Change this...
+$y->options->{ts} = '101';
+
+is(
+   resource_diff($x, $y),
+   1,
+   "Small diff in 1 attrib"
 );
 
 # #############################################################################