Req #74551 [Opn]: json_encode() assumes that one dimensional array is an object

Edit report at https://bugs.php.net/bug.php?id=74551&edit=1 ID: 74551 User updated by: jon dot ronnenberg at gmail dot com Reported by: jon dot ronnenberg at gmail dot com Summary: json_encode() assumes that one dimensional array is an object Status: Open Type: Feature/Change Request Package: JSON related Operating System: Linux Ubuntu Mate 16.04 PHP Version: 7.0.18 Block user comment: N Private report: N New Comment: The Test script should have been: $array = [0,1,2]; print_r(json_encode($array, JSON_PRETTY_PRINT)); unset($array[1]); print_r(json_encode($array, JSON_PRETTY_PRINT)); Previous Comments: ------------------------------------------------------------------------ [2017-05-06 13:20:43] jon dot ronnenberg at gmail dot com Description: ------------ <?php ## json_encode() assumes that one dimensional array is an object ## # Note, To run the entire bug report in php, just copy/paste the entire # content into a php file and run php your_file.ph # Unsetting an element will also remove the keys. # json_encode() will now assume that this is an object, # and will encode it as such. # ref: http:#php.net/manual/en/function.json-encode.php#94157 # Note, that JSON_PRETTY_PRINT has no effect on the behavior # Example: $array = [0,1,2]; print_r(json_encode($array, JSON_PRETTY_PRINT)); unset($array[1]); print_r(json_encode($array, JSON_PRETTY_PRINT)); # The real issue and bug introducing confusing comes with array_filter. # Example: $array = [0,1,2,3,4,5,6,7,8,9,10]; $odds = function($d) { return $d % 2; }; print_r(json_encode(array_filter($array, $odds), JSON_PRETTY_PRINT)); # The work-around is to always use array_values, when you know that you will # serialize a one dimensional array. # Example: $array = [0,1,2,3,4,5,6,7,8,9,10]; $odds = function($d) { return $d % 2; }; print_r(json_encode(array_values(array_filter($array, $odds)), JSON_PRETTY_PRINT)); # Since the data manipulation is often handled in other layers than the # serialization, this can lead to subtle and hard to trace bugs. # Often only found when deployed since this does not happen in all cases, # as shown below. # Example: $array = [0,1,2,3,4,5,6,7,8,9,10]; $below2 = function($d) { return $d < 2; }; print_r(json_encode(array_filter($array, $below2), JSON_PRETTY_PRINT)); # Changing the behavior of array_filter might introduce breaking change # while changing how json_encode handles one dimensional arrays should # not. # I'm not filing this as a bug, since it has been reported seven years # ago, but it definitely tangents a bug. # Seven years ago, simoncpu, reported this behavior in the User Contributed Notes, # http://php.net/manual/en/function.json-encode.php#94157 # Another bug report touches on the subject: # https://bugs.php.net/bug.php?id=45162 # But it's hard to distill what the author expect or believe to be wrong # with the behavior. # This report tries to be concise and has nothing to do with associative arrays. ?> Test script: --------------- # The two print_r statements should output the same: $array = [0,1,2]; print_r(json_encode($array, JSON_PRETTY_PRINT)); unset($array[1]); print_r(json_encode($array, JSON_PRETTY_PRINT Expected result: ---------------- [ 0, 1, 2 ][ 0, 1, 2 ] Actual result: -------------- [ 0, 1, 2 ]{ "0": 0, "2": 2 } ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=74551&edit=1