SCRIPT_DEBUG check in print_emoji_detection_script() generating PHP Notices

[aut0poietic]

Some simple (or poorly built) WordPress themes generate the following PHP notice in 4.2:

Notice: Use of undefined constant SCRIPT_DEBUG - assumed 'SCRIPT_DEBUG' in /var/www/html/wordpress/docs.oucpm.org/wp-includes/formatting.php on line 4144

In addition to the notice, the emoji script block is printed using the expanded (rather than minified) form.

The Notice is triggered when the active theme does not enqueue any scripts (I know, right?).

Unless added to the config.php, SCRIPT_DEBUG is not defined until a script is enqueued (in wp-includes/script-loader.php).

The the two issues can be resolved by checking to ensure SCRIPT_DEBUG is defined ( as is done in other files that use SCRIPT_DEBUG).

Current:

//wp-includes/formatting.php:4144
if ( SCRIPT_DEBUG ) {
...

Fix:

wp-includes/formatting.php:4144
if ( defined('SCRIPT_DEBUG') && SCRIPT_DEBUG ) {
...

Edge case it is, but googling has turned up a pretty sizable chunk of these.

[azaozz]

Wondering if we should define SCRIPT_DEBUG the same way we define WP_DEBUG in wp_initial_constants(). Probably not a good idea for a dot release though.

[Craig Ralston]

define SCRIPT_DEBUG in wp_initial_constants()

[azaozz]

32118.diff is not going to work properly. See how it is defined now in script-loader.php: https://core.trac.wordpress.org/browser/tags/4.2/src/wp-includes/script-loader.php#L51 (defaults to true when running from /src).

The question is: can this possibly conflict with something a plugin would do if we move it to wp_initial_constants()?

[nacin]

Let's not deal with early defining SCRIPT_DEBUG for now. I am almost positive we don't do that because of the weirdness of script-loader.php loading.

For 4.2.1, the extra defined() && is good.

Question: what happens when this bug occurs? What happens when the notice is suppressed vs not suppressed? Does the JS break?

[Craig Ralston]

I wasn't able to replicate any JS actually breaking from the notice not being suppressed. @aut0poietic if you experienced different results, please feel free to chime in.

32118.diff didn't include the full move from script-loader.php, my fault. 32118-2.diff just adds the extra defined('SCRIPT_DEBUG') && and stays out of default-constants.php

[iseulde]

@Craig Ralston Could you update the patch so that it follows the coding standards?
​https://make.wordpress.org/core/handbook/coding-standards/php/#space-usage

[Craig Ralston]

correcting spacing from 32118-2.diff

[azaozz]

What happens when this bug occurs? What happens when the notice is suppressed vs not suppressed? Does the JS break?

There is an unsightly PHP notice at the top of the page when the server is misconfigured. The JS doesn't break but the non-minified JS is used (as the undefined constant is treated as string, evaluates to true). Happens when the notice is suppressed and not suppressed.

[SergeyBiryukov]

In 32296:

Check if SCRIPT_DEBUG is defined before using it in print_emoji_detection_script().

props Craig Ralston.
fixes #32118 for trunk.

[azaozz]

Now this breaks when running from /src :)

Testing with a theme that doesn't enqueue scripts or styles, and with SCRIPT_DEBUG not defined in wp-config.php, there is an "Uncaught SyntaxError: Unexpected string" because the "build" version of the script is outputted: https://core.trac.wordpress.org/browser/tags/4.2/src/wp-includes/formatting.php#L4175.

Perhaps we can keep the above fix for 4.2 but add something better in trunk.

[DrewAPicture]

Looks like we're going to need a new patch, see comment:13.

[azaozz]

In 32482:

Check if running from /src or SCRIPT_DEBUG is defined in print_emoji_detection_script().
See #32118.

[SergeyBiryukov]

#32461 was marked as a duplicate.

[azaozz]

In 33315:

Check if running from /src or SCRIPT_DEBUG is defined in print_emoji_detection_script().
Fixes #32118 for 4.2.