After running the changed files for a few days, I found this in one of the Error Reporting plugin log files
E_WARNING
Unknown class passed as parameter at …../wp-includes/class-IXR.php (326)
referring to a is_subclass_of line. My initial thought was that the unknown class was a non-existant class passed as the first argument. Realizing that this could be prevented by testing for is_object before testing for get_class or is_subclass_of, I ran some more tests.
Using IS object AND (IS class OR IS subclass), instancof, and is_a
Using IS NOT object OR (IS NOT class AND IS NOT subclass), !instancof, and !is_a
And testing an $object that was not a class, a class but not the parent class or a subclass, a subclass, and an instance of the parent class, yielded the following summarized run times
Not obj iogciso 22 iof 32 isa 63 Not obj !iogciso 23 iof 33 !isa 66 other obj iogciso 94 iof 36 isa 99 other obj !iogciso 93 iof 36 !isa 102 sub obj iogciso 96 iof 35 isa 98 sub obj !iogciso 94 iof 35 !isa 99 parent obj iogciso 49 iof 36 isa 103 parent obj !iogciso 47 iof 36 !isa 101
As can be seen, all conditional tests were more or less faster when testing a non-object. But when the $object was a class, the addition of the is_object generally negated any perfomance improvements over is_a.
Still uncertain as to whether or not this would in fact prevent possible E_WARNING errors, I read the PHP documentation again and this time noticed
In PHP 5.0, is_a() was deprecated and replaced by the instanceof operator. There were some issues with the initial implementation of instanceof, which relied on __autoload() to search for missing classes. If the class was not present, instanceof would throw a fatal E_ERROR due to the failure of __autoload() to discover that class. The same behaviour occurred in the catch operator and the is_subclass_of() function, for the same reason.
None of these functions or operators call __autoload() in PHP 5.1.x, and the class_exists() workarounds used in code written for PHP 5.0.x, while not problematic in any way, are no longer necessary.
So, as is_subclass_of has the same problems as the instanceof operator, why not just use the easier to read conditional?
Because first testing for is_object had some performance benefit when the $object was a non-class, I put together conditionals that tested for is_class and then used version_compare to determine the value of the PHP_VERSION constant and tested for either instanceof or is_a based on the version. Unfortunately version_compare slowed things down considerably, in some cases more than twice as long as is_object AND (get_class OR is_subclass_of)
Other than testing for the PHP version, the autoload problem can also be avoided by using a string variable in place of the string in both instanceof and is_subclass_of. Because testing for is_object either ran slightly slower or slightly faster depending on the $object, I again ran tests using is_a, instanceof, and get_class OR is_subclass_of conditionals without testing for is_object, this time testing for non-object, other object, subclass, and parent class. Because the NOT conditionals proved to be similar to the IS conditionals I did not test them. Again for 4400000 (4 million 400 thousand) iterations, and running each variation only once this time, the run times were
$test_obj = null $test_name = 'nonClass' isa: F isa_run_time: 63.8112490177 iof: F iof_run_time: 27.4505140781 gciso: F gciso_run_time: 37.5824019909 $test_obj = null $test_name = 'subClass' isa: F isa_run_time: 62.1618340015 iof: F iof_run_time: 36.1470940113 gciso: F gciso_run_time: 38.2189328671 $test_obj = null $test_name = 'parentClass' isa: F isa_run_time: 64.0376930237 iof: F iof_run_time: 31.3636629581 gciso: F gciso_run_time: 37.3621349335 $test_obj = otherClass $test_name = 'nonClass' isa: F isa_run_time: 94.293446064 iof: F iof_run_time: 31.2466518879 gciso: F gciso_run_time: 71.0462958813 $test_obj = otherClass $test_name = 'subClass' isa: F isa_run_time: 105.786374092 iof: F iof_run_time: 38.7829210758 gciso: F gciso_run_time: 80.2897667885 $test_obj = otherClass $test_name = 'parentClass' isa: F isa_run_time: 102.1823318 iof: F iof_run_time: 34.5454649925 gciso: F gciso_run_time: 74.7066178322 $test_obj = subClass $test_name = 'nonClass' isa: F isa_run_time: 93.7578001022 iof: F iof_run_time: 30.5689721107 gciso: F gciso_run_time: 69.8373310566 $test_obj = subClass $test_name = 'subClass' isa: T isa_run_time: 103.760252953 iof: T iof_run_time: 38.9862082005 gciso: T gciso_run_time: 35.7183160782 $test_obj = subClass $test_name = 'parentClass' isa: T isa_run_time: 98.5362439156 iof: T iof_run_time: 35.4245359898 gciso: T gciso_run_time: 77.2220799923 $test_obj = parentClass $test_name = 'nonClass' isa: F isa_run_time: 94.5036940575 iof: F iof_run_time: 30.6256258488 gciso: F gciso_run_time: 69.396201849 $test_obj = parentClass $test_name = 'subClass' isa: F isa_run_time: 103.611497879 iof: F iof_run_time: 39.3666779995 gciso: F gciso_run_time: 81.0174598694 $test_obj = parentClass $test_name = 'parentClass' isa: T isa_run_time: 100.992965221 iof: T iof_run_time: 35.7687740326 gciso: T gciso_run_time: 35.2318360806
![[PDA - Heathcare NOT Warfare - Sign the Petition.]](http://www.mittineague.com/blog/tmp/HealthNotWar_final.jpg)
