Gutenberg 16.4 Footnotes Critical Bug on PHP 8.0

[orangeavocad0]

I am currently using WordPress version 6.3, PHP 8.0.

There is no issue initially when creating a post with the footnotes block, and is able to publish the post.

After a while, when trying to edit the same post again, I will see the critical error as such as seen in the attachment.

PHP Fatal error: Uncaught TypeError: count(): Argument #1 ($value) must be of type Countable|array, null given in /wordpress/plugins/gutenberg/16.4.0/build/block-library/blocks/footnotes.php:37 Stack trace: #0 /wordpress/core/6.3/wp-includes/class-wp-block.php(258): gutenberg_render_block_core_footnotes(Array, '', Object(WP_Block)) #1 /wordpress/core/6.3/wp-includes/blocks.php(1133): WP_Block->render() #2 /wordpress/core/6.3/wp-includes/blocks.php(1171): render_block(Array) #3 /wordpress/core/6.3/wp-includes/class-wp-hook.php(310): do_blocks('<!-- wp:rank-ma...') #4 /wordpress/core/6.3/wp-includes/plugin.php(205): WP_Hook->apply_filters('<!-- wp:rank-ma...', Array) #5 /wordpress/core/6.3/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php(1864): apply_filters('the_content', '<!-- wp:rank-ma...') #6 /wordpress/core/6.3/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php(569): WP_REST_Posts_Controller->prepare_item_for_response(Object(WP_Post), Object(WP_REST_Request)) #7 /wordpress/core/6.3/wp-includes/rest-api/class-wp-rest-server.php(1188): WP_REST_Posts_Controller->get_item(Object(WP_REST_Request)) #8 /wordpress/core/6.3/wp-includes/rest-api/class-wp-rest-server.php(1035): WP_REST_Server->respond_to_request(Object(WP_REST_Request), '/wp/v2/posts/(?...', Array, NULL) #9 /wordpress/core/6.3/wp-includes/rest-api.php(545): WP_REST_Server->dispatch(Object(WP_REST_Request)) #10 /wordpress/core/6.3/wp-includes/rest-api.php(2911): rest_do_request(Object(WP_REST_Request)) #11 [internal function]: rest_preload_api_request(Array, '/wp/v2/posts/57...') #12 /wordpress/core/6.3/wp-includes/block-editor.php(743): array_reduce(Array, 'rest_preload_ap...', Array) #13 /wordpress/core/6.3/wp-admin/edit-form-blocks.php(77): block_editor_rest_api_preload(Array, Object(WP_Block_Editor_Context)) #14 /wordpress/core/6.3/wp-admin/post.php(187): require('/wordpress/core...') #15 {main} thrown in /wordpress/plugins/gutenberg/16.4.0/build/block-library/blocks/footnotes.php on line 37	

[ramonopoly]

Are there any steps to reproduce this?

I tried using 6.3 on PHP 8.0 but couldn't.

Even so, I've added a bit of defensive code to the footnotes block in ​https://github.com/WordPress/gutenberg/pull/53660 just in case.

Edit: And Gutenberg 16.4 :)

[orangeavocad0]

Replying to ramonopoly:

Are there any steps to reproduce this?

I tried using 6.3 on PHP 8.0 but couldn't.

Even so, I've added a bit of defensive code to the footnotes block in ​https://github.com/WordPress/gutenberg/pull/53660 just in case.

Edit: And Gutenberg 16.4 :)

I tried but sometimes the bug happens, sometimes it doesn't. Not very sure what is the trigger for this fatal error.

Actually when it occurred for my site, the Happiness Engineer thought that it was plugin conflict but after doing some testing, there isn't any plugin conflict.

I clearly see the fatal error in the site logs about the footnotes. :)

One thing to highlight is that downgrading to PHP 7.4 reduced the fatal error to a warning but it still caused other errors in the editor. Additionally, even though it was just a warning, the footnotes is not rendering in page. For example, see this post - ​https://blog.pastething.com/2023/08/09/economics-navigate-automated-world/#universal-basic-income-a-beacon-of-hope-or-just-a-mirage

I think the site log I posted earlier is the best I can provide for now :(

[ramonopoly]

Thanks for the quick reply @orangeavocad0

I think I might have found a way to reproduce:

​https://github.com/WordPress/gutenberg/pull/53660#issuecomment-1678407868

[chaplin89]

Hello. Same problem here. WP 6.3 with PHP 8.1.

 Fatal error: Uncaught Error: count(): Argument #1 ($value) must be of type Countable|array, null given
in /home/customer/www/mywebsite/public_html/wp-includes/blocks/footnotes.php on line 37

[johanneswilm]

I assume the problem is fixed if one upgrades to Gutenberg 16.5.0? How does one then manually fix footnotes in existing posts?

[ramonopoly]

I assume the problem is fixed if one upgrades to Gutenberg 16.5.0? How does one then manually fix footnotes in existing posts?

Testing a fix over here: ​https://github.com/WordPress/gutenberg/pull/53713

In the meantime you could either go into the database in wp_postmeta itself and escape the quotations, or use a filter similar to the one in the above PR.

[hellofromTonya]

This issue was already reported upstream in the Gutenberg repo ​https://github.com/WordPress/gutenberg/issues/53397.

As the report is with the Gutenberg plugin and the Footnotes block is maintained within Gutenberg, I'll close this ticket as reported upstream. The discussion can shift to that issue and follow-up work is needed, it'll happen in that repo.

@orangeavocad0 @chaplin89 are you still experiencing this issue? If yes, please reopen ​this Gutenberg issue and share the details there please. Thank you