fix(admin-bar): prevent strpos() null deprecation on invalid API key

[faisalahammad]

Summary

Fixes PHP 8.1+ strpos() deprecation warning when hovering the Imagify admin bar menu with an invalid API key. The fix casts plan_label to string before passing it to strpos().

Fixes #961

Problem

When the API key is invalid, User::init_user() gets a WP_Error from get_imagify_user() and returns early without calling set_user_properties(). This leaves plan_label as null. When the admin bar profile AJAX fires, null is passed to strpos() in admin-bar-status.php, triggering:

PHP Deprecated: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated
in views/admin/admin-bar-status.php on line 4

Solution

Cast $data['plan_label'] to (string) at the point of use in the view template. This is the minimal defensive fix — null becomes '', strpos('', '_') returns false, and the label displays as empty. No behavioral change for valid API keys.

Changes

views/admin/admin-bar-status.php

Before:

$pos        = strpos( $data['plan_label'], '_' );
$plan_label = false !== $pos ? substr( $data['plan_label'], 0, $pos ) : $data['plan_label'];

After:

$plan_label_value = (string) $data['plan_label'];
$pos              = strpos( $plan_label_value, '_' );
$plan_label       = false !== $pos ? substr( $plan_label_value, 0, $pos ) : $plan_label_value;

Why this works:
(string) cast converts null to '', satisfying PHP 8.1+'s strict type requirement for strpos(). When plan_label is a valid string (e.g. "free", "growth_monthly"), behavior is unchanged.

Testing

Manual Testing

Invalid API key:

1. Fresh install Imagify, enter an invalid API key, save
2. Hover Imagify in admin bar
3. Check debug.log → no strpos() deprecation

Valid API key:

1. Enter a valid API key, save
2. Hover Imagify admin bar → plan info displays correctly

Automated Tests

$ composer test-unit
OK, but incomplete, skipped, or risky tests!
Tests: 24, Assertions: 59, Risky: 5.

All 24 tests pass. The 5 risky tests are pre-existing (unrelated version_compare() and ReflectionProperty deprecations).

Screen recording

https://videos.faisalahammad.com/recordings/Ti6Hma9pi0Xdgi8xPut3