Uncaught Error: Call to a member function exists() on boolean .../admin/AmazonAI-PollyService.php:291

[MaximOrlovsky]

Every time a I publish or update the post I get the following error:

PHP Fatal error:  Uncaught Error: Call to a member function exists() on boolean in /site/public/wp-content/plugins/amazon-polly/admin/AmazonAI-PollyService.php:291

Stack trace:
#0 /site/public/wp-content/plugins/amazon-polly/admin/AmazonAI-PollyService.php(111): AmazonAI_PollyService->convert_to_audio(2838460, '22050', 'Matthew', Array, true, '')"
#1 /site/public/wp-includes/class-wp-hook.php(286): AmazonAI_PollyService->generate_audio(2838460)
POST /wp-admin/admin-post.php" 500
#2 /site/public/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters('', Array)
#3 /site/public/wp-includes/plugin.php(515): WP_Hook->do_action(Array)
#4 /site/public/wp-content/plugins/amazon-polly/admin/AmazonAI-BackgroundTask.php(93): do_action_ref_array('amazon_polly_ba...', Array)
#5 /site/public/wp-includes/class-wp-hook.php(286): AmazonAI_BackgroundTask->run('')
#6 /site/public/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters('', Array)
#7 /site/public/wp-includes/plugin.php(453): WP_Hook->do_action(Array)
#8 /site/public/..."

[MaximOrlovsky]

Why you use $wp_filesystem?

It's always boolean true on my instance, and never WP_Filesystem_* object

[tstachlewski]

Hi,
Because this is the standard way of interacting with file system (https://codex.wordpress.org/Filesystem_API) - your error is a bit unusual, I have never seen it before. Which WordPress version are you using? Is it managed version?
Cheers,

[MaximOrlovsky]

WordPress 5.0.3 (the latest at the moment)
PHP-FPM 7.1
Apache 2.4

I rewrote all used filesystem functions to direct functions. Like $wp_filesystem->delete( $file_temp_full_name ) to unlink( $file_temp_full_name ) and it works, but It drops me from any plugin updates.

Finding a better solution would be great.