mod_quizgame: Add Backup / Restore support

[sbourget]

Proposed patch adds backup / restore support to mod_quizgame.
Fixes issue #31

[xow]

Thanks @sbourget. Unfortunately I'm getting

Notice: Undefined property: stdClass::$userid in /home/john/www/moodle/mod/quizgame/backup/moodle2/restore_quizgame_stepslib.php on line 52

[sbourget]

Thanks @xow. I just added a commit to fix that. Could you take another look?

[xow]

Unfortunately seems to error out when you attempt to restore to a different course (because the question bank is not available there maybe?)

Debug info: ERROR: invalid input syntax for integer: "1,2"
SELECT * FROM mdl_backup_ids_temp WHERE backupid = $1 AND itemname = $2 AND itemid = $3
[array (
0 => '28945923630efa63a48b7b80ea4973b2',
1 => 'question_category',
2 => '1,2',
)]
Error code: dmlreadexception

[sbourget]

Any chance you can post a copy of the backup file? I cannot reproduce the issue here (MacOS / My SQL) I've been able to create the backup, delete the original course including the question category & questions, then restore the backup creating a new course. I've been able to play the game successfully in this new course accessing all of the original questions.

What context are your questions / question categories in (course / category/ or system?)

[sbourget]

I was finally able to reproduce the issue and have added a fix. It seems sometimes the questioncategory field is just holding the ID, while other times it is holding the id,context for the corresponding category in the question bank. I've added logic to the restore code to check to see what we are working with, and then to handle it appropriately.

[xow]

Thanks @sbourget for fixing that! Unfortunately now I get the following error

Backup is missing XML file: [tempdir]/backup/017dd7ec37ee0f0d1655d9bd61a0f968/activities/quizgame_2/grades.xml

[sbourget]

@xow, I'm a bit confused on that error. What options are you using when creating the backup? Are you backing up the whole course or just the activity?

[xow]

Just the activity on the front page... must be a bit of an edge case!

[sbourget]

@xow, Not sure if there is much I can do in that scenario. I've added some additional logging, but it seems activity backups MAY not include everything we would need to restore the instance. (for example, If you select a question category that is assigned to the course context or higher and perform the activity only backup, the question category is not actually included in the backup, even though the dependency is marked. This seems to be an issue with moodle core, and I'm not sure how to even approach trying to fix that)

How would you suggest I proceed from here?

[xow]

Thanks @sbourget. I tried course restore and had the same error (or similar)

However I thought it would be worth merging this even if it's not perfect (especially if it's a core problem). Because at least in most cases it will work. Thanks again!

[sbourget]

Thanks @xow I'll look at putting together some automated (behat) tests for backup/restore once I finish fixing issue #22 and fix the debugging notice from issue #35