1. Autosave works in some ways just like a normal save. We ultimately
call $behaviour->process_save() to do the work, and create a new step to
hold the data.
2. However, we come in through a completely different route through the
API, starting with separate auto-save methods. This keeps the auto-save
changes mostly separate, and so reduced the chance of breaking existing
working code.
3. When the time comes to store the auto-save step in the database, we
save it using a negative sequence number.
This is a clever trick that not only distinguises these steps, but also
avoids unique key errors when an auto-save and a real action happen
simultaneously. (There are unit tests for these tricky edge cases.)
4. When we load the data back from the database, most of the time the
auto-save steps are loaded back as if they were a real save, and so the
auto-saved data is used when the question is then rendered.
5. However, before we process another action, we remove the auto-saved
step, so it does not appear in the final history.
While doing this, I found various bugs in the manages question types admin page, and so fixed them, and updated the code
there to use $OUTPUT and html_writer.
AMOS BEGIN
MOV [cannotdeletemissingqtype,admin],[cannotdeletemissingqtype,question]
MOV [cannotdeleteqtypeinuse,admin],[cannotdeleteqtypeinuse,question]
MOV [cannotdeleteqtypeneeded,admin],[cannotdeleteqtypeneeded,question]
MOV [deleteqtypeareyousure,admin],[deleteqtypeareyousure,question]
MOV [deleteqtypeareyousuremessage,admin],[deleteqtypeareyousuremessage,question]
MOV [deletingqtype,admin],[deletingqtype,question]
MOV [numquestions,admin],[numquestions,question]
MOV [numquestionsandhidden,admin],[numquestionsandhidden,question]
MOV [qtypedeletefiles,admin],[qtypedeletefiles,question]
MOV [uninstallqtype,admin],[uninstallqtype,question]
AMOS END
Tim Hunt