Not quite sure how to create patches (kinda rushed so I'll figure that out later). So for now I'll paste the methods as they now stand. Our bugzilla number for this bug is 6750

/*

• Backup the data in the question
  *
• This is used in question/backuplib.php
  */
  function backup($bf,$preferences,$question,$level=6) {

$status = true;

// ou-specific begins export standard moodle backups bug #6750
/*

• Moodle core forgets to backup the 'question_match' table. We need to
• add it. The 'question_match_sub' is backed up in it's place. To fit
• in with this the records for 'question_match' will be included under
• the tag 'MATCH_DEFINITIONS' so as not to break the standard moodle
• backup.
  */
  $records = get_records('question_match', 'question', $question, 'id ASC');

if(function_exists('ou_backup_writeRecordsToFile')){ $status = ou_backup_writeRecordsToFile($bf, $records, 6, 'MATCH_DEFINITIONS', 'MATCH_DEFINITION'); }
// ou-specific ends export standard moodle backups

$records = get_records('question_match_sub', 'question', $question, 'id ASC');
//If there are matchs
if ($records) {
$status = fwrite ($bf,start_tag("MATCHS",6,true));
//Iterate over each match
foreach ($records as $match) { $status = fwrite ($bf,start_tag("MATCH",7,true)); //Print match contents fwrite ($bf,full_tag("ID",8,false,$match->id)); fwrite ($bf,full_tag("CODE",8,false,$match->code)); fwrite ($bf,full_tag("QUESTIONTEXT",8,false,$match->questiontext)); fwrite ($bf,full_tag("ANSWERTEXT",8,false,$match->answertext)); $status = fwrite ($bf,end_tag("MATCH",7,true)); }
$status = fwrite ($bf,end_tag("MATCHS",6,true));
}
return $status;
}

/*

• Restores the data in the question
  *
• This is used in question/restorelib.php
  */
  function restore($old_question_id,$new_question_id,$info,$restore) {

$status = true;

//Get the matchs array
$matchs = $info'#'['MATCHS']['0']'#'['MATCH'];

//We have to build the subquestions field (a list of match_sub id)
$subquestions_field = "";
$in_first = true;

//Iterate over matchs
for($i = 0; $i < sizeof($matchs); $i++) {
$mat_info = $matchs[$i];

//We'll need this later!!
$oldid = backup_todb($mat_info'#'['ID']['0']'#');

//Now, build the question_match_SUB record structure
$match_sub = new stdClass;
$match_sub->question = $new_question_id;
$match_sub->code = isset($mat_info'#'['CODE']['0']'#')?backup_todb($mat_info'#'['CODE']['0']'#'):'';
if (!$match_sub->code) { $match_sub->code = $oldid; }
$match_sub->questiontext = backup_todb($mat_info'#'['QUESTIONTEXT']['0']'#');
$match_sub->answertext = backup_todb($mat_info'#'['ANSWERTEXT']['0']'#');

//The structure is equal to the db, so insert the question_match_sub
$newid = insert_record ("question_match_sub",$match_sub);

//Do some output
if (($i+1) % 50 == 0) {
if (!defined('RESTORE_SILENTLY')) {
echo ".";
if (($i+1) % 1000 == 0) { echo "<br />"; }
}
backup_flush(300);
}

if ($newid) {
//We have the newid, update backup_ids
backup_putid($restore->backup_unique_code,"question_match_sub",$oldid,
$newid);
//We have a new match_sub, append it to subquestions_field
if ($in_first) { $subquestions_field .= $newid; $in_first = false; } else { $subquestions_field .= ",".$newid; }
} else { $status = false; }
}

//We have created every match_sub, now create the match

// ou-specific begins export standard moodle backups bug #6750
/*
* Moodle core forgets to backup the 'question_match' table. We need to
* add it. The 'question_match_sub' is backed up in it's place. To fit
* in with this the records for 'question_match' will be included under
* the tag 'MATCH_DEFINITIONS' so as not to break the standard moodle
* backup.
*/
// Get the match definitions from the backup file to the db.
$records = null;
if(isset($info'#'['MATCH_DEFINITIONS']) && isset($info'#'['MATCH_DEFINITIONS']['0']'#'['MATCH_DEFINITION'])){ $records = $info['#']['MATCH_DEFINITIONS']['0']['#']['MATCH_DEFINITION']; }
if(isset($records) && function_exists('ou_restore_getRecordsFromFileToDB')){ $status = ou_restore_getRecordsFromFileToDB($restore, $records, $new_question_id, 'question_match', 'question'); }

/* deleted
*
$match = new stdClass;
$match->question = $new_question_id;
$match->subquestions = $subquestions_field;

//The structure is equal to the db, so insert the question_match_sub
$newid = insert_record ("question_match",$match);

if (!$newid) { $status = false; }
*/
// ou-specific ends export standard moodle backups

return $status;
}


function restore_recode_answer($state, $restore) {

//The answer is a comma separated list of hypen separated math_subs (for question and answer)
$answer_field = "";
$in_first = true;
$tok = strtok($state->answer,",");
//ou-specific begins inc backup bug #6750
$match_ans = null;
//ou-specific begins inc backup
while ($tok) {
//Extract the match_sub for the question and the answer
$exploded = explode("-",$tok);

$match_question_id = $exploded[0];
$match_answer_id = $exploded[1];

//Get the match_sub from backup_ids (for the question)
if (!$match_que = backup_getid($restore->backup_unique_code,"question_match_sub",$match_question_id)) { echo 'Could not recode question in question_match_sub '.$match_question_id.'<br />'; }
//Get the match_sub from backup_ids (for the answer)
if ($match_answer_id) { // only recode answer if not 0, not answered yet
//ou-specific begins inc backup bug #6750
$match_answer_id = get_field('question_match_sub', 'id', 'code', $match_answer_id);
//ou-specific ends inc backup
if (!$match_ans = backup_getid($restore->backup_unique_code,"question_match_sub",$match_answer_id)) { echo 'Could not recode answer in question_match_sub '.$match_answer_id.'<br />'; }
}

if ($match_que) {
//If the question hasn't response, it must be 0
if (!$match_ans and $match_answer_id == 0) { $match_ans->new_id = 0; }

if ($in_first) { $answer_field .= $match_que->new_id."-".$match_ans->new_id; $in_first = false; } else { $answer_field .= ",".$match_que->new_id."-".$match_ans->new_id; }
}
//check for next
$tok = strtok(",");
}
return $answer_field;
}


To save having to manually write out the db field to xml field translations I created helper methods for backup and restore. These methods are in the files ou_restoreling.php and ou_backuplib.php respectively with the files included in backuplib.php and restorelib.php.
/*
* Write the fields from an object to the backup file
* @param object $bf backup file passed in
* @param int $indent level of indentation
* @param array array of records to backup
* @param string $name name to call the xml elements created
*/
function ou_backup_writeRecordsToFile($bf, $records, $indent=0, $element_plural, $element_single){

$status = true;

if (!$records) { return $status; }

//If there are records
$status = fwrite ($bf,start_tag($element_plural,$indent,true));

$indent++;
//Iterate over each record
foreach ($records as $record) {
$status = fwrite ($bf,start_tag($element_single,$indent,true));
//Print record contents
foreach($record as $field => $value){ fwrite ($bf,full_tag(strtoupper($field),$indent+1,false,$value)); }
$status = fwrite ($bf,end_tag($element_single,$indent,true));
}
$indent--;
$status = fwrite ($bf,end_tag($element_plural,$indent,true));

return $status;
}

/*
* Get item records from the backup xml file and save to the database
* @param object $preferences preferences object that controls the restore,
* @param array $records set of item records ,
* @param int $new_id,
* @param string $table table to insert records to.
* @param string $id_field name of the field to assign $new_id to
*/
function ou_restore_getRecordsFromFileToDB($preferences, $records, $new_id, $table, $id_field) {

$status = true;
$field_name = null;

//Iterate over records
for($i = 0; $i < sizeof($records); $i++) {
if(empty($records[$i]'#')){ continue; }

$record = $records[$i]'#';
//We'll need this later!!
$oldid = backup_todb($record['ID']['0']'#');

//Now, build the record structure
$db_record = new stdClass;

//Iterate over each record
foreach ($record as $field => $value) { $field_name = strtolower($field); $db_record->$field_name = backup_todb($record[$field]['0']['#']); }

//$id_field will be set within the previous loop so set it correctly here.
$db_record->$id_field = $new_id;

//The structure is equal to the db, so insert the record
$newid = insert_record ($table,$db_record);

//Do some output
if (($i+1) % 50 == 0) {
if (!defined('RESTORE_SILENTLY')) {
echo ".";
if (($i+1) % 1000 == 0) { echo "<br />"; } }
}
backup_flush(300);
}

if ($newid) { //We have the newid, update backup_ids backup_putid($preferences->backup_unique_code,$table,$oldid, $newid); } else { $status = false; }
}

return $status;
}

The select some files in that view, and do create patch from the context menu.

For other options see http://docs.moodle.org/en/Development:How_to_create_a_patch.

Also, code like ou_backup_writeRecordsToFile/ou_restore_getRecordsFromFileToDB is nice in abstract, and probably backup and restore should have had something like that from the start, but unfortunately, in core at the moment, consistency is more important.

So I will probably reimplement your fix in the next couple of days, but at least it is very clear what I have to do. Sorry or thanks, whichever you feel is more appropriate.

Atleast you could make sense of it.

col