WXR import incorrectly handles comment ID's, Results in threading being lost

[DD32]

The Export'd WXR files & Import process contains the original Comment ID, and Comment Parent ID allready. However, Upon import, the Comment ID's are re-assigned, however the parent ID's are not.

The result is that the comment threading is lost entirely.

Eg: Previously comment 1234 was in reply to comment 1222, however, comment 1222 is now comment 22, but comment 1234 still has '1222' as its parent_id.

2 options are possible:

• Remapping the comment parent ID's
• Preserving the comment ID's

The only issue i see with preserving the comment ID's is that importing into another blog with comments allready could cause conflicts, which would require remapping of some comment ID's regardless.

[ryan]

[9100] is how we fixed this for posts.

[ryan]

Too big a job for 2.7. Let's shoot for early 2.8 with a possible backport to a 2.7 dot release.

[janeforshort]

Punting due to feature freeze. Reconsider with next release.

[tott]

I am currently testing a patch that preserves the comment_IDs where possible. This solves most of the issues. I will attach the patch after some more testing.

[lloydbudd]

With threaded commenting in core with 2.7, now more threading in the wild. Raising priority. Depending on 2.8 release status and nature of the solution should consider getting in 2.8 .

[joostdevalk]

Patch

[joostdevalk]

WXR File I used to test the patch

[joostdevalk]

I'd like to get this in in 2.8, I think it's a pretty simple and solid patch which solves a major annoyance...

[Denis-de-Bernardy]

IRC discussion for reference:

[09:30] <jdevalk> basically threw all comments into an array, sort them by id, remapped the wxr id's to the new id's and attach the correct parent
[09:31] <jdevalk> also working on a plugin that let's you import wxr files that are on the server, so you're not capped by HTTP upload restraints
[09:31] <ddebernardy> I take it you tested before/after with your data already, no?
[09:31] <jdevalk> yes.
[09:33] <ddebernardy> patch's logic seems correct
[09:33] <jdevalk> yeah it's not too hard
[09:34] <ddebernardy> an alternative method, which might be more robust, could be re-key the comments array based on parents
[09:34] <ddebernardy> array ( comment_parent => comments )
[09:34] <ddebernardy> and then do a double foreach loop
[09:34] <jdevalk> not sure i follow? :)
[09:35] <ddebernardy> well, it would cover the case where a weirdo plays with his database
[09:35] <ddebernardy> and ends up with comment IDs in an order than hasn't much to do with the comments date or hierarchy
[09:35] <ddebernardy> but it's such an edge case that we can ignore it imo
[09:36] <jdevalk> yeah i think so too

Safe to commit imo.

[Denis-de-Bernardy]

can wait until 2.9

[Denis-de-Bernardy]

unless someone wants to try it...

[Denis-de-Bernardy]

per discussion in IRC

[Denis-de-Bernardy]

let's give the double array approach a try, just in case.

​http://core.trac.wordpress.org/ticket/8019#comment:9

[ocean90]

I want to test the patch but I get an error on WP and WPMU 2.8.4:

Parse error: syntax error, unexpected T_VARIABLE, expecting T_FUNCTION in .../wordpress.php on line 529

Is there something new?
Would be nice if the bug can be fixed.

[ocean90]

Sorry, my mistake.

It works now. Thanks.

[michaelh]

Assuming the correct advice was provided, this fix didn't solve the problem according to this Forum thread:

​http://wordpress.org/support/topic/312843

[michaelh]

Replying to michaelh:

Assuming the correct advice was provided, this fix didn't solve the problem

Retracting that statement as the patch wordpress.php.diff does in fact fix the threaded comment problem at 2.8.4:

​http://wordpress.org/support/topic/312843?replies=17#post-1225031

[azaozz]

Is this good to go?

[Denis-de-Bernardy]

if we make the assumption that they're tossed in, in the correct order, it worked fine a few months back.

there were some talks of using a double foreach loop in the event they weren't. but it's mostly an improvement over the current patch.

[tott]

Replying to azaozz:

Is this good to go?

I tested against current trunk. Works fine as import on an empty blog as well as when importing on a blog which already has post/comment ids provided in the import. This should cover most cases and all further items would be improvements to this patch.

[ryan]

Refreshed patch that applies against trunk. Needs testing.

[ryan]

(In [12301]) Preserve parentage when importing comments. Props joostdevalk. fixes #8019

[voyagerfan5761]

I assume that blogs which already have imported content will have to delete and re-import their comments to receive any benefits from this patch?