Hi Robin,
Many thanks for your reply. We had understood that a revision was a ‘snap shot’ of an entry at a given moment; as in a single block of data which contained everything needed to re-create it.
This particular issue is concerned with third-party field types which stored their data in proprietary tables (Playa, Matrix, et al).
In EE 2.2, before the _prepare_data() method is called, the revision_post data in the array contains everything submitted from the form. So, for example, if we had a Matrix field the data for this would look something like this:
["field_id_3"]=>
array(3) {
["row_order"]=>
array(2) {
[0]=>
string(8) "row_id_6"
[1]=>
string(9) "row_new_0"
}
["row_id_6"]=>
array(3) {
["col_id_1"]=>
string(19) "One man went to moe"
["col_id_2"]=>
string(19) "2011-06-15 09:39 AM"
["col_id_3"]=>
array(1) {
["selections"]=>
array(2) {
[0]=>
string(0) ""
[1]=>
string(1) "4"
}
}
}
["row_new_0"]=>
array(3) {
["col_id_1"]=>
string(19) "Two men went to moe"
["col_id_2"]=>
string(18) "2011-06-22 9:40 AM"
["col_id_3"]=>
array(1) {
["selections"]=>
array(2) {
[0]=>
string(0) ""
[1]=>
string(1) "2"
}
}
}
}
Now, in EE2.2, within the _prepare_data() method all third-party data is removed from the revision_post array by the field’s save() methods, e.g. line 1589 of Api_challen_entries.php
$data[$field_name] = $this->EE->api_channel_fields->apply('save', array($data[$field_name]));
so coming back from this method all we are left with in our revision_post array is:
["field_id_3"]=>
string(1) "1"
So, if this data is stored in the revision table it will be represent an incomplete entry.
My logic may be off here, but it looks as though if an entry was subsequently edited again deleting the third-party data, and you then wanted to roll back to a previous revision, that revision would not contain the *old* third-party data as this had not been stored anywhere. Is this not a potential issue with EE’s native revisions (with third party content) now?
For our Add-on we have found a way of caching the revision_post data using the entry_submission_start hook and re-instating it later. This seems to work but is clearly at odds with the native EE revision behaviour as it stands in 2.2.
I guess I have two questions:
1. Have I misunderstood the way EE revisions work and is there another method of retrieving third party data from an earlier version other than from the data saved in the revisions table?
2. If we base our draft version on the revision_post data as it exists when the entry_submission_start hook is executed, are we going to run into problems down the line?
I hope this all makes sense. I’m more than happy to write this up more completely if it helps.
Many thanks and best wishes,
Malcolm