icingaweb2/application/views/scripts/error/error.phtml

<?php if (! $this->compact && ! $hideControls): ?>
<div class="controls">
    <?= $tabs ?>
</div>
<?php endif ?>
<div class="content">
<div class="clipboard-wrapper">
<button type="button"
        class="copy-to-clipboard"
        data-icinga-clipboard
        tabindex="-1"
        data-copied-label="<?= $this->translate('Copied') ?>"
        title="<?= $this->translate('Copy to clipboard') ?>"
>
    <i class="icon fa fa-clone"></i>
</button>
<div class="error-message-wrapper" data-clipboard-source>
<?php
if (isset($stackTraces)) {
    foreach ($messages as $i => $message) {
        echo '<p class="error-message">' . nl2br($this->escape($message)) . '<br></p>'
            . '<hr>'
            . '<pre>' . $this->escape($stackTraces[$i]) . '<br></pre>';
    }
} else {
    foreach ($messages as $message) {
        echo '<p class="error-message">' . nl2br($this->escape($message)) . '</p>';
    }
}

$libraries = \Icinga\Application\Icinga::app()->getLibraries();
$coreReason = [];
$modReason = [];

if (isset($requiredVendor, $requiredProject) && $requiredVendor && $requiredProject) {
    // TODO: I don't like this, can we define requirements somewhere else?
    $coreDeps = ['icinga-php-library' => '>= 0.20.0', 'icinga-php-thirdparty' => '>= 0.15.0'];

    foreach ($coreDeps as $libraryName => $requiredVersion) {
        if (! $libraries->has($libraryName)) {
            $coreReason[] = sprintf($this->translate(
                'Library "%s" is required and missing. Please install a version of it matching the required one: %s'
            ), $libraryName, $requiredVersion);
        } elseif (! $libraries->has($libraryName, $requiredVersion) && $libraries->get($libraryName)->isRequired($requiredVendor, $requiredProject)) {
            $coreReason[] = sprintf($this->translate(
                'Library "%s" is required and installed, but its version (%s) does not satisfy the required one: %s'
            ), $libraryName, $libraries->get($libraryName)->getVersion() ?: '-', $requiredVersion);
        }
    }

    if (! empty($coreReason)) {
        array_unshift($coreReason, $this->translate('You have unmet dependencies. Please check Icinga Web 2\'s installation instructions.'));
    }
}

if (isset($module)) {
    $manager = \Icinga\Application\Icinga::app()->getModuleManager();
    if ($manager->hasUnmetDependencies($module->getName())) {
        if (isset($requiredModule) && $requiredModule && isset($module->getRequiredModules()[$requiredModule])) {
            if (! $manager->hasInstalled($requiredModule)) {
                $modReason[] = sprintf($this->translate(
                    'Module "%s" is required and missing. Please install a version of it matching the required one: %s'
                ), $requiredModule, $module->getRequiredModules()[$requiredModule]);
            } elseif (! $manager->hasEnabled($requiredModule)) {
                $modReason[] = sprintf($this->translate(
                    'Module "%s" is required and installed, but not enabled. Please enable module "%1$s".'
                ), $requiredModule);
            } elseif (! $manager->has($requiredModule, $module->getRequiredModules()[$requiredModule])) {
                $modReason[] = sprintf($this->translate(
                    'Module "%s" is required and installed, but its version (%s) does not satisfy the required one: %s'
                ), $requiredModule, $manager->getModule($requiredModule, false)->getVersion(), $module->getRequiredModules()[$requiredModule]);
            }
        } elseif (isset($requiredVendor, $requiredProject) && $requiredVendor && $requiredProject) {
            foreach ($module->getRequiredLibraries() as $libraryName => $requiredVersion) {
                if (! $libraries->has($libraryName)) {
                    $modReason[] = sprintf($this->translate(
                        'Library "%s" is required and missing. Please install a version of it matching the required one: %s'
                    ), $libraryName, $requiredVersion);
                } elseif (! $libraries->has($libraryName, $requiredVersion) && $libraries->get($libraryName)->isRequired($requiredVendor, $requiredProject)) {
                    $modReason[] = sprintf($this->translate(
                        'Library "%s" is required and installed, but its version (%s) does not satisfy the required one: %s'
                    ), $libraryName, $libraries->get($libraryName)->getVersion() ?: '-', $requiredVersion);
                }
            }
        }

        if (! empty($modReason)) {
            array_unshift($modReason, sprintf($this->translate(
                'This error might have occurred because module "%s" has unmet dependencies.'
                . ' Please check it\'s installation instructions and install missing dependencies.'
            ), $module->getName()));
        }
    }
}

// The following doesn't use ipl\Html because that's what the error possibly is about
?>
</div>
</div>
<?php if (! empty($coreReason)): ?>
<div class="error-reason">
<?php endif ?>
<?php foreach ($coreReason as $msg): ?>
    <p><?= $msg ?></p>
<?php endforeach ?>
<?php if (! empty($coreReason)): ?>
</div>
<?php endif ?>

<?php if (! empty($modReason)): ?>
<div class="error-reason">
<?php endif ?>
<?php foreach ($modReason as $msg): ?>
    <p><?= $msg ?></p>
<?php endforeach ?>
<?php if (! empty($modReason)): ?>
</div>
<?php endif ?>
</div>