Graph-Preview not working on Release 1.5 after Upgrade

[Squier115]

Describe the bug
After Upgrading from Version 1.0 in our prod_environment the hover/preview on the links ist not working anymore. In the preview only a hashvalue ist displayed and Errors in the Log are created. When i click on that link, the correct graph ist displayed under the 'graph-section'.

2026-02-17 08:00:37 - CMDPHP PHP ERROR NOTICE Backtrace: (/plugins/weathermap/weathermap-cacti-plugin.php[308]:weathermap_singleview(), /plugins/weathermap/weathermap-cacti-plugin.php[389]:weathermap_mapselector(), /plugins/weathermap/weathermap-cacti-plugin.php[831]:CactiErrorHandler()) 2026-02-17 08:00:37 - ERROR PHP NOTICE in Plugin 'weathermap': Undefined variable: nullhash in file: /media/local-data0/cacti/plugins/weathermap/weathermap-cacti-plugin.php on line: 831 2026-02-17 08:00:37 - CMDPHP PHP ERROR NOTICE Backtrace: (/plugins/weathermap/weathermap-cacti-plugin.php[308]:weathermap_singleview(), /plugins/weathermap/weathermap-cacti-plugin.php[389]:weathermap_mapselector(), /plugins/weathermap/weathermap-cacti-plugin.php[831]:CactiErrorHandler()) 2026-02-17 08:00:37 - ERROR PHP NOTICE in Plugin 'weathermap': Undefined variable: nullhash in file: /media/local-data0/cacti/plugins/weathermap/weathermap-cacti-plugin.php on line: 831 2026-02-17 08:00:37 - CMDPHP PHP ERROR NOTICE Backtrace: (/plugins/weathermap/weathermap-cacti-plugin.php[308]:weathermap_singleview(), /plugins/weathermap/weathermap-cacti-plugin.php[389]:weathermap_mapselector(), /plugins/weathermap/weathermap-cacti-plugin.php[831]:CactiErrorHandler()) 2026-02-17 08:00:37 - ERROR PHP NOTICE in Plugin 'weathermap': Undefined variable: nullhash in file: /media/local-data0/cacti/plugins/weathermap/weathermap-cacti-plugin.php on line: 831 2026-02-17 08:00:37 - CMDPHP PHP ERROR NOTICE Backtrace: (/plugins/weathermap/weathermap-cacti-plugin.php[308]:weathermap_singleview(), /plugins/weathermap/weathermap-cacti-plugin.php[389]:weathermap_mapselector(), /plugins/weathermap/weathermap-cacti-plugin.php[831]:CactiErrorHandler()) 2026-02-17 08:00:37 - ERROR PHP NOTICE in Plugin 'weathermap': Undefined variable: nullhash in file: /media/local-data0/cacti/plugins/weathermap/weathermap-cacti-plugin.php on line: 831 2026-02-17 08:00:37 - CMDPHP PHP ERROR NOTICE Backtrace: (/plugins/weathermap/weathermap-cacti-plugin.php[308]:weathermap_singleview(), /plugins/weathermap/weathermap-cacti-plugin.php[389]:weathermap_mapselector(), /plugins/weathermap/weathermap-cacti-plugin.php[831]:CactiErrorHandler()) 2026-02-17 08:00:37 - ERROR PHP NOTICE in Plugin 'weathermap': Undefined variable: nullhash in file: /media/local-data0/cacti/plugins/weathermap/weathermap-cacti-plugin.php on line: 831 2026-02-17 08:00:37 - CMDPHP PHP ERROR NOTICE Backtrace: (/plugins/weathermap/weathermap-cacti-plugin.php[308]:weathermap_singleview(), /plugins/weathermap/weathermap-cacti-plugin.php[389]:weathermap_mapselector(), /plugins/weathermap/weathermap-cacti-plugin.php[831]:CactiErrorHandler()) 2026-02-17 08:00:37 - ERROR PHP NOTICE in Plugin 'weathermap': Undefined variable: nullhash in file: /media/local-data0/cacti/plugins/weathermap/weathermap-cacti-plugin.php on line: 831 2026-02-17 08:00:37 - CMDPHP PHP ERROR NOTICE Backtrace: (/plugins/weathermap/weathermap-cacti-plugin.php[308]:weathermap_singleview(), /plugins/weathermap/weathermap-cacti-plugin.php[389]:weathermap_mapselector(), /plugins/weathermap/weathermap-cacti-plugin.php[831]:CactiErrorHandler()) 2026-02-17 08:00:37 - ERROR PHP NOTICE in Plugin 'weathermap': Undefined variable: nullhash in file: /media/local-data0/cacti/plugins/weathermap/weathermap-cacti-plugin.php on line: 831 2026-02-17 08:00:37 - CMDPHP PHP ERROR NOTICE Backtrace: (/plugins/weathermap/weathermap-cacti-plugin.php[308]:weathermap_singleview(), /plugins/weathermap/weathermap-cacti-plugin.php[389]:weathermap_mapselector(), /plugins/weathermap/weathermap-cacti-plugin.php[831]:CactiErrorHandler()) 2026-02-17 08:00:37 - ERROR PHP NOTICE in Plugin 'weathermap': Undefined variable: nullhash in file: /media/local-data0/cacti/plugins/weathermap/weathermap-cacti-plugin.php on line: 831 2026-02-17 08:00:37 - CMDPHP PHP ERROR NOTICE Backtrace: (/plugins/weathermap/weathermap-cacti-plugin.php[308]:weathermap_singleview(), /plugins/weathermap/weathermap-cacti-plugin.php[389]:weathermap_mapselector(), /plugins/weathermap/weathermap-cacti-plugin.php[831]:CactiErrorHandler()) 2026-02-17 08:00:37 - ERROR PHP NOTICE in Plugin 'weathermap': Undefined variable: nullhash in file: /media/local-data0/cacti/plugins/weathermap/weathermap-cacti-plugin.php on line: 831 2026-02-17 08:00:37 - CMDPHP PHP ERROR NOTICE Backtrace: (/plugins/weathermap/weathermap-cacti-plugin.php[308]:weathermap_singleview(), /plugins/weathermap/weathermap-cacti-plugin.php[389]:weathermap_mapselector(), /plugins/weathermap/weathermap-cacti-plugin.php[831]:CactiErrorHandler()) 2026-02-17 08:00:37 - ERROR PHP NOTICE in Plugin 'weathermap': Undefined variable: nullhash in file: /media/local-data0/cacti/plugins/weathermap/weathermap-cacti-plugin.php on line: 831

Did i miss something?
I can provide everything u need. Cactiversion is 1.2.25
Expected behavior
When hover over a Link in a certain weathermap the graph from that link will be displayed.

Screenshots
If applicable, add screenshots to help explain your problem.

Plugin (please complete the following information):

• Version: 1.5
• Source: source-code from this repo

Desktop (please complete the following information):

• OS: Testing-Notebook (Win11)
• Browser: Firefox
• Version: 147.0.3

Additional context
Add any other context about the problem here.

[somethingwithproof]

Root cause identified: $nullhash is uninitialized when the map matching $current_id appears after the first group header in iteration order.

foreach ($maps as $map) {
    if ($current_id == $map['id']) {
        $nullhash = $map['filehash'];   // only set if current map is in this iteration
    }
}

// Later:
print "<option ... value='$nullhash'>";  // uninitialized if first group header comes before current map

Fix: initialize $nullhash = ''; before the first foreach loop, or move the assignment outside the conditional.

See also the full weathermap audit: #203, #204, #205, #206, #207, #208, #209, #210, #211, #212.