wp_load_image() attempts to load directories

[primehalo]

The wp_load_image() function in /wp-includes/media.php does a file_exists() check on the $file parameter, but that will return TRUE for both files and directories. There is no check to make sure $file is actually a file instead of a directory.

[benkulbertis]

added is_file check to wp_load_image()

[nacin]

We can likely combine this into the ! file_exists() check above it, and use the same string.

[kirasong]

Updated patch for WP_Image_Editor.

[kirasong]

Updated patch​ to include WP_Image_Editor, and the file-name change for wp_load_image (since the function is now deprecated).

Related: #6821

[scribu]

Couldn't we just replace the file_exists() check with is_file() instead of calling both?

[kirasong]

Just check with is_file()

[kirasong]

Replying to scribu:

Couldn't we just replace the file_exists() check with is_file() instead of calling both?

You're right, looks like we can!
Went ahead and updated the patch​. Will write up a quick unit test for this later today, if no-one else gets to it first.

[kirasong]

Initial Unit Test.

[kirasong]

Initial unit test attached​. At the moment, errors upon wp_load_image() failure. Going to see if there's a better way to do this.

[nacin]

In 22463:

In WP_Image_Editor / wp_load_image(), use is_file() rather than file_exists() so we do not accidentally load a directory.

props benkulbertis, DH-Shredder, scribu.
fixes #17814.