Refactoring: Replace dirname(__FILE__) With Corresponding Constant

[Sdfendor]

Description (*)

dirname(__FILE__) returns the directory of the current file. Since PHP 5.3.0 the constant __DIR__ exists and is equivalent to the function call (see Magic constants). At the same time it's easier to grasp at first glance. Our current minimum supported PHP version is 7.3.0.
The PR replaces all dirname(__FILE__) calls with DIR except those in lib/Zend and lib/phpseclib which are in the process of being removed from the codebase to become externally maintained dependencies.

Questions or comments

In two instances dirname(dirname(__FILE__)) is replaced with dirname(__DIR__). Another variant here would be dirname(__FILE__),2) (directory name above the current one). I've chosen the first option but have no disposition which one better to use. Maybe some of you have an opinion regarding e.g. ease of understanding?

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All automated tests passed successfully (all builds are green)

[fballiano]

I like dirname(DIR) because:

• didn't even know dirname had a second parameter
• this way we always use DIR instead of mixing DIR and FILE

[Sdfendor]

didn't even know dirname had a second parameter

The php documentation states only since 7.0 so it at least wasn't always there 😅.

[sreichel]

Agree with both, but for me this is more clear ... b/c i see we look one level above ...

dirname(dirname(__FILE__))
dirname(__FILE__, 2)

[github-actions]

Unit Test Results

1 files  ±0  1 suites  ±0   0s ⏱️ ±0s
0 tests ±0  0 ✔️ ±0  0 💤 ±0  0 ❌ ±0 
7 runs  ±0  5 ✔️ ±0  2 💤 ±0  0 ❌ ±0 

Results for commit 7f56d79. ± Comparison against base commit ef1b965.