custom field duplicated

[ericr23]

When I enter the information for a custom field and click on Preview without first clicking Add Custom Field, the custom field is saved. But then when I click Publish, it is saved again, appearing in the post twice.

If I click Add Custom Field before Preview, subsequent Publish does not duplicate the custom field. But it is very convenient and efficient to be able to avoid a separate save of the custom field.

[scribu]

I guess you'll just have to click the "Add Custom Field" button before saving.

[hakre]

I was able to reproduce with 2.9:

1. edit an existing post.
2. enter text in the name and value textboxes under Custom Fields.
3. press the Preview Changes button.
4. close the newly opened browser tab.
5. press the Publish button.
6. post now has two times the same custom field.

I was not able to reproduce when javascript is deactivated.

I think the last information is important to drill down to the cause of the bug.

[westi]

Tested in 2.8.4 and this bug exists there to.

Steps to reproduce:

1. Create a new draft post.
2. Enter a name and value but don't save the field
3. Preview the post
4. Publish the post

Moving to 3.0 as this is not a regression and there is currently know patch to fix the issue.

We should avoid these accidental duplicate custom fields but I don't think that this is a severe bug which needs fixing in a maintenance release.

[scribu]

This will not be a problem, if we fix the root cause: #10905

[hakre]

I can not say if that is the actual root cause, I assume something related to the workflow in the frontend javacript not reflecting a changed status in the persistent storage layer on the server-side.

But #10905 might prevent the duplicate add. But it won't prevent that the frontend tries to add again. Or is it the server side when I press publish. hmm.

=> First fix #10905

[hakre]

Can still confirm against current trunk. Might not be javascript related but this must be a check performed on save draft / publish post. Tried an alternative test:

1. Create a new draft post.
2. Enter a name and value but don't save the field
3. Preview the post
4. Add additional text in the posts content
5. Preview the post again
6. Publish the post

That results in more additional fields. So not only the publish but the preview save-action needs to handle custom field duplicates properly, draft fields maybe?

The evolved suggestion in #10905 to extend the API functions might be really usefull to deal with this case.

[SergeyBiryukov]

Closed #20344 as a duplicate.

[collinsinternet]

Changed from add_post_meta to update_post_meta to resolve issue of duplication.

[collinsinternet]

Last patch was exported incorrectly.

[MikeHansenMe]

refreshed from src dir

[MikeHansenMe]

I was able to confirm this bug (not every try though). I was not able to reproduce it at all after applying the patch. 11465.3.diff​ is a refresh from the src dir.

[MikeHansenMe]

11465.3.diff​ still applies. This is a simple change and fixes the issue.

[sabernhardt]

This can happen in 6.0 (beta 2), including with the block editor.

11465.3.diff seems to fix it.

[sabernhardt]

Changing to update_post_meta() overwrites values if you want multiple values for a key (see ticket:47576#comment:1), so this would need a different patch.