Remove dependency on posix_getpid() and detect if installed about moodle-tool_lockstats

[mudrd8mz]

The actual error message is not probably relevant here. I believe there is some other error/exception raised that kills PHP, and this message "A lock was created but not released" is just a consequence.

[mudrd8mz]

I am getting somewhere. As I suspected, there was another exception thrown which was silently swallowed and not reported - or better it was overruled by the lock exception . After I applied the following change:

diff --git a/lib/classes/lock/lock.php b/lib/classes/lock/lock.php
index 7b117c3..6ee1380 100644
--- a/lib/classes/lock/lock.php
+++ b/lib/classes/lock/lock.php
@@ -114,6 +114,7 @@ class lock {
         if (!$this->released && defined('PHPUNIT_TEST')) {
             $key = $this->key;
             $this->release();
+            return;
             throw new \coding_exception("A lock was created but not released at:\n" .
                                         $this->caller . "\n\n" .
                                         " Code should look like:\n\n" .

and attempted to run a task, I finally got

Default exception handler: Exception - Call to undefined function tool_lockstats\posix_getpid() Debug: 
Error code: generalexceptionmessage
* line 234 of /admin/tool/lockstats/classes/proxy_lock_factory.php: Error thrown
* line 148 of /admin/tool/lockstats/classes/proxy_lock_factory.php: call to tool_lockstats\proxy_lock_factory->log_lock()
* line 127 of /admin/tool/task/cli/schedule_task.php: call to tool_lockstats\proxy_lock_factory->get_lock()

which I was able to confirm - the site's PHP was built without the POSIX functions.

However, I think it reveals a problem in the Moodle core code as it hides the real cause why an exception was thrown.

[mudrd8mz]

Indeed. It checks defined('PHPUNIT_TEST') which is always true. Going to fix this upstream.

[mudrd8mz]

https://tracker.moodle.org/browse/MDL-59546

[brendanheywood]

thanks @mudrd8mz - although it still seems like there is probably something missing re posix_getpid()

Is the posix extension something we can assume moodle requires (it isn't in core admin/environment.xml) or should I declare that in my environment.xml ?

[mudrd8mz]

As per http://php.net/manual/en/posix.installation.php POSIX functions are enabled by default in PHP. But yeah, they can be still disabled so it may be wise to put them into environment.xml. Although there is still https://tracker.moodle.org/browse/MDL-52319

Maybe in this particular case, you can simply check if function exists before calling it. And if it is not available, just store an empty value (and then display as a dash or question mark) instead of PID? As I understood it, it is an information for the admin only, not essential for the plugin functionality.

[brendanheywood]

Cool, I'll reopen this and remove that hard dependancy