WP 3.9 - PHP Warnings in Customizer if Theme has set a default image for Custom Header

[MH Themes]

I just noticed a bug which did not appear in WP 3.8.3. When a theme has defined a default image for custom header support like:

$header = array(
	'default-image'	=> get_template_directory_uri() . '/images/logo.png',
	'default-text-color' => '000',
	'width' => 300,
	'height' => 100,
	'flex-width' => true,
	'flex-height' => true
);
add_theme_support('custom-header', $header);

The customizer outputs PHP warnings when loading:

Warning: Invalid argument supplied for foreach() in /Applications/MAMP/htdocs/wordpress/wp-admin/custom-header.php on line 1248
Warning: array_merge(): Argument #2 is not an array in /Applications/MAMP/htdocs/wordpress/wp-admin/custom-header.php on line 1268
Warning: Invalid argument supplied for foreach() in /Applications/MAMP/htdocs/wordpress/wp-admin/custom-header.php on line 1248
Warning: array_merge(): Argument #2 is not an array in /Applications/MAMP/htdocs/wordpress/wp-admin/custom-header.php on line 1268

If I comment out:

'default-image'	=> get_template_directory_uri() . '/images/logo.png'

Then everything works fine. Except that there is no default image defined anymore. ;-)

[obenland]

Introduced in r27849.

Themes can specify a default image without registering it as a default header.
In that scenario $this->default_headers would be null.

[kovshenin]

There's also the same warning in reset_header_image(), fixed by the same patch.

[ocean90]

#27913 was marked as a duplicate.

[SergeyBiryukov]

This appears to be a regression introduced in [27849]. Restoring the correct version number.

[SergeyBiryukov]

#27913 was marked as a duplicate.

[nacin]

Tested by jeremyfelt. Assigning to me for final review, since I wrote this code.

[nacin]

In 28275:

Custom header: Avoid warnings in the process_default_headers() method.

props obenland.
fixes #27850.

[nacin]

In 28277:

Custom header: Avoid warnings in the process_default_headers() method.

Merges [28275] to the 3.9 branch.

props obenland.
fixes #27850.