Twenty Ten, Eleven and Twelve: PHP notices due to undefined vars in attachment template

[nabil_kadimi]

I got a few errors while viewing attachments

Notice: Undefined variable: k in... 

To reproduce:

• Show E_NOTICE errors
• Display the page for any attachment, e.g: ​http://example.com/?attachment_id=115

[lancewillett]

Thanks for the report. Can you tell us how to repeat, maybe what kind of attachment you were viewing? Was it an image or something else?

[nabil_kadimi]

Replying to lancewillett:

Thanks for the report. Can you tell us how to repeat, maybe what kind of attachment you were viewing? Was it an image or something else?

I tried with an image and got these errors.

To reproduce:

• Enable E_NOTICE errors
• Enable Twentyten or Twentytwelve
• Go to the page for an image like ​http://example.com/?attachment_id=115 (I didn't test with other types)

[nabil_kadimi]

I reinstalled from trunk and was able to see one more error, patch updated

[SergeyBiryukov]

The only way for $k to be empty here is for get_children() to return an empty array a few lines above. I could not reproduce that. Do you have a plugin or a custom function that modifies all queries via pre_get_posts filter?

We could just move $k++; to the if ( count( $attachments ) > 1 ) branch a few lines below. However, it seems like we're patching the symptom here rather than the root cause.

[nabil_kadimi]

SergeyBiryukov You caught me red-handed, that was Polylang. My apologies.

[SergeyBiryukov]

I guess we should still avoid the notice here.

28361.2.patch​ moves $k++ to the if ( count( $attachments ) > 1 ) branch and also makes adjacent_image_link() more consistent with get_adjacent_post_link(), which has a check for a valid post object: tags/3.9.1/src/wp-includes/link-template.php#L1807​.

[nabil_kadimi]

That's awesome, thanks.

[SergeyBiryukov]

In 28584:

Avoid a PHP notice in adjacent_image_link() if no images were found.

props nabil_kadimi.
see #28361.

[SergeyBiryukov]

In 28585:

Avoid a PHP notice in bundled themes if no images were found.

props nabil_kadimi.
fixes #28361.