Handle empty Order increment prefix

[elidrissidev]

Description (*)

A call to strpos with an empty needle would throw a warning pre PHP 8.0. This change will check if the prefix is not empty first before performing the call to strpos.

Fixed Issues (if relevant)

1. Fixes strpos(): Empty needle if Order Increment Prefix is an empty string #1645

Manual testing scenarios (*)

1. Make sure you're on PHP 7.x as this warning is not thrown in PHP 8.0
2. Execute the following query to set an empty prefix for order increment ids:

update eav_entity_store set increment_prefix = '' where entity_type_id = '5';

3. Try to create an order from the Admin and a similar error should show up:

Order saving error: Warning: strpos(): Empty needle in /var/www/openmage/app/code/core/Mage/Eav/Model/Entity/Increment/Numeric.php on line 48

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)

[Flyingmana]

fix Syntax error

[github-actions]

Unit Test Results

1 files  ±0  1 suites  ±0   0s ⏱️ ±0s
0 tests ±0  0 ✔️ ±0  0 💤 ±0  0 ❌ ±0 
6 runs  ±0  4 ✔️ ±0  2 💤 ±0  0 ❌ ±0 

Results for commit 95d52d3. ± Comparison against base commit 7f84c55.