Fix PHP notice when opening the edit image popup

[Mista-Flo]

Hi there, I noticed a PHP notice on the last trunk version while playing with the media library.

Steps to reproduce:

• Activate Query Monitor plugin
• Open your web console
• Go to upload.php page on the backend
• Select grid mode
• Click on an attachment image
• Click on 'Edit image' button
• An edit image popup loads, and you should see a PHP notice saying that $msg->error is undefined

[Mista-Flo]

Can you please try to reproduce the issue? Just to be sure it's not something related to me, but when looking at the code, it seems better to check that errors property exist in error object, otherwise it can throw an error anyway.

[SergeyBiryukov]

Thanks for the report! I was able to reproduce the issue.

[SergeyBiryukov]

Appears to be a regression in [48375] / #47147.

[Mista-Flo]

Thank you Sergey, nice catch :)

[SergeyBiryukov]

In 48946:

Media: In wp_ajax_image_editor(), check if the error property exists before accessing it.

This avoids a PHP notice when editing an image.

Follow-up to [48375].

Props Mista-Flo.
Fixes #51251.

[SergeyBiryukov]

Reopening for backporting to the 5.5 branch.

[SergeyBiryukov]

In 48956:

Media: In wp_ajax_image_editor(), check if the error property exists before accessing it.

This avoids a PHP notice when editing an image.

Follow-up to [48375].

Props Mista-Flo.
Merges [48946] to the 5.5 branch.
Fixes #51251.

[SergeyBiryukov]

#51655 was marked as a duplicate.