src/PEAR/Task/Postinstallscript.php
function validateXml($pkg, $xml, $config, $fileXml)
    {
        if ($fileXml['role'] != 'php') {
            return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
            $fileXml['name'] . '" must be role="php"');
        }
        PEAR::pushErrorHandling(PEAR_ERROR_RETURN);
        $file = $pkg->getFileContents($fileXml['name']);
        if (PEAR::isError($file)) {
            PEAR::popErrorHandling();
            return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                $fileXml['name'] . '" is not valid: ' .
                $file->getMessage());
        } elseif ($file === null) {
            return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                $fileXml['name'] . '" could not be retrieved for processing!');
        } else {
            $analysis = $pkg->analyzeSourceCode($file, true);
            if (!$analysis) {
                PEAR::popErrorHandling();
                $warnings = '';
                foreach ($pkg->getValidationWarnings() as $warn) {
                    $warnings .= $warn['message'] . "\n";
                }
                return array(PEAR_TASK_ERROR_INVALID, 'Analysis of post-install script "' .
                    $fileXml['name'] . '" failed: ' . $warnings);
            }
            if (count($analysis['declared_classes']) != 1) {
                PEAR::popErrorHandling();
                return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                    $fileXml['name'] . '" must declare exactly 1 class');
            }
            $class = $analysis['declared_classes'][0];
            if ($class != str_replace(array('/', '.php'), array('_', ''),
                  $fileXml['name']) . '_postinstall') {
                PEAR::popErrorHandling();
                return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                    $fileXml['name'] . '" class "' . $class . '" must be named "' .
                    str_replace(array('/', '.php'), array('_', ''),
                    $fileXml['name']) . '_postinstall"');
            }
            if (!isset($analysis['declared_methods'][$class])) {
                PEAR::popErrorHandling();
                return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                    $fileXml['name'] . '" must declare methods init() and run()');
            }
            $methods = array('init' => 0, 'run' => 1);
            foreach ($analysis['declared_methods'][$class] as $method) {
                if (isset($methods[$method])) {
                    unset($methods[$method]);
                }
            }
            if (count($methods)) {
                PEAR::popErrorHandling();
                return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                    $fileXml['name'] . '" must declare methods init() and run()');
            }
        }
        PEAR::popErrorHandling();
        $definedparams = array();
        $tasksNamespace = $pkg->getTasksNs() . ':';
        if (!isset($xml[$tasksNamespace . 'paramgroup']) && isset($xml['paramgroup'])) {
            // in order to support the older betas, which did not expect internal tags
            // to also use the namespace
            $tasksNamespace = '';
        }
        if (isset($xml[$tasksNamespace . 'paramgroup'])) {
            $params = $xml[$tasksNamespace . 'paramgroup'];
            if (!is_array($params) || !isset($params[0])) {
                $params = array($params);
            }
            foreach ($params as $param) {
                if (!isset($param[$tasksNamespace . 'id'])) {
                    return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                        $fileXml['name'] . '" <paramgroup> must have ' .
                        'an ' . $tasksNamespace . 'id> tag');
                }
                if (isset($param[$tasksNamespace . 'name'])) {
                    if (!in_array($param[$tasksNamespace . 'name'], $definedparams)) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" ' . $tasksNamespace .
                            'paramgroup> id "' . $param[$tasksNamespace . 'id'] .
                            '" parameter "' . $param[$tasksNamespace . 'name'] .
                            '" has not been previously defined');
                    }
                    if (!isset($param[$tasksNamespace . 'conditiontype'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" ' . $tasksNamespace .
                            'paramgroup> id "' . $param[$tasksNamespace . 'id'] .
                            '" must have a ' . $tasksNamespace .
                            'conditiontype> tag containing either "=", ' .
                            '"!=", or "preg_match"');
                    }
                    if (!in_array($param[$tasksNamespace . 'conditiontype'],
                          array('=', '!=', 'preg_match'))) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" ' . $tasksNamespace .
                            'paramgroup> id "' . $param[$tasksNamespace . 'id'] .
                            '" must have a ' . $tasksNamespace .
                            'conditiontype> tag containing either "=", ' .
                            '"!=", or "preg_match"');
                    }
                    if (!isset($param[$tasksNamespace . 'value'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" ' . $tasksNamespace .
                            'paramgroup> id "' . $param[$tasksNamespace . 'id'] .
                            '" must have a ' . $tasksNamespace .
                            'value> tag containing expected parameter value');
                    }
                }
                if (isset($param[$tasksNamespace . 'instructions'])) {
                    if (!is_string($param[$tasksNamespace . 'instructions'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" ' . $tasksNamespace .
                            'paramgroup> id "' . $param[$tasksNamespace . 'id'] .
                            '" ' . $tasksNamespace . 'instructions> must be simple text');
                    }
                }
                if (!isset($param[$tasksNamespace . 'param'])) {
                    continue; // <param> is no longer required
                }
                $subparams = $param[$tasksNamespace . 'param'];
                if (!is_array($subparams) || !isset($subparams[0])) {
                    $subparams = array($subparams);
                }
                foreach ($subparams as $subparam) {
                    if (!isset($subparam[$tasksNamespace . 'name'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" parameter for ' .
                            $tasksNamespace . 'paramgroup> id "' .
                            $param[$tasksNamespace . 'id'] . '" must have ' .
                            'a ' . $tasksNamespace . 'name> tag');
                    }
                    if (!preg_match('/[a-zA-Z0-9]+/',
                          $subparam[$tasksNamespace . 'name'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" parameter "' .
                            $subparam[$tasksNamespace . 'name'] .
                            '" for ' . $tasksNamespace . 'paramgroup> id "' .
                            $param[$tasksNamespace . 'id'] .
                            '" is not a valid name.  Must contain only alphanumeric characters');
                    }
                    if (!isset($subparam[$tasksNamespace . 'prompt'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" parameter "' .
                            $subparam[$tasksNamespace . 'name'] .
                            '" for ' . $tasksNamespace . 'paramgroup> id "' .
                            $param[$tasksNamespace . 'id'] .
                            '" must have a ' . $tasksNamespace . 'prompt> tag');
                    }
                    if (!isset($subparam[$tasksNamespace . 'type'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" parameter "' .
                            $subparam[$tasksNamespace . 'name'] .
                            '" for ' . $tasksNamespace . 'paramgroup> id "' .
                            $param[$tasksNamespace . 'id'] .
                            '" must have a ' . $tasksNamespace . 'type> tag');
                    }
                    $definedparams[] = $param[$tasksNamespace . 'id'] . '::' .
                    $subparam[$tasksNamespace . 'name'];
                }
            }
        }
        return true;
    }
function validateXml($pkg, $xml, $config, $fileXml)
    {
        if ($fileXml['role'] != 'php') {
            return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
            $fileXml['name'] . '" must be role="php"');
        }
        PEAR::pushErrorHandling(PEAR_ERROR_RETURN);
        $file = $pkg->getFileContents($fileXml['name']);
        if (PEAR::isError($file)) {
            PEAR::popErrorHandling();
            return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                $fileXml['name'] . '" is not valid: ' .
                $file->getMessage());
        } elseif ($file === null) {
            return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                $fileXml['name'] . '" could not be retrieved for processing!');
        } else {
            $analysis = $pkg->analyzeSourceCode($file, true);
            if (!$analysis) {
                PEAR::popErrorHandling();
                $warnings = '';
                foreach ($pkg->getValidationWarnings() as $warn) {
                    $warnings .= $warn['message'] . "\n";
                }
                return array(PEAR_TASK_ERROR_INVALID, 'Analysis of post-install script "' .
                    $fileXml['name'] . '" failed: ' . $warnings);
            }
            if (count($analysis['declared_classes']) != 1) {
                PEAR::popErrorHandling();
                return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                    $fileXml['name'] . '" must declare exactly 1 class');
            }
            $class = $analysis['declared_classes'][0];
            if ($class != str_replace(array('/', '.php'), array('_', ''),
                  $fileXml['name']) . '_postinstall') {
                PEAR::popErrorHandling();
                return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                    $fileXml['name'] . '" class "' . $class . '" must be named "' .
                    str_replace(array('/', '.php'), array('_', ''),
                    $fileXml['name']) . '_postinstall"');
            }
            if (!isset($analysis['declared_methods'][$class])) {
                PEAR::popErrorHandling();
                return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                    $fileXml['name'] . '" must declare methods init() and run()');
            }
            $methods = array('init' => 0, 'run' => 1);
            foreach ($analysis['declared_methods'][$class] as $method) {
                if (isset($methods[$method])) {
                    unset($methods[$method]);
                }
            }
            if (count($methods)) {
                PEAR::popErrorHandling();
                return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                    $fileXml['name'] . '" must declare methods init() and run()');
            }
        }
        PEAR::popErrorHandling();
        $definedparams = array();
        $tasksNamespace = $pkg->getTasksNs() . ':';
        if (!isset($xml[$tasksNamespace . 'paramgroup']) && isset($xml['paramgroup'])) {
            // in order to support the older betas, which did not expect internal tags
            // to also use the namespace
            $tasksNamespace = '';
        }
        if (isset($xml[$tasksNamespace . 'paramgroup'])) {
            $params = $xml[$tasksNamespace . 'paramgroup'];
            if (!is_array($params) || !isset($params[0])) {
                $params = array($params);
            }
            foreach ($params as $param) {
                if (!isset($param[$tasksNamespace . 'id'])) {
                    return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                        $fileXml['name'] . '" <paramgroup> must have ' .
                        'an ' . $tasksNamespace . 'id> tag');
                }
                if (isset($param[$tasksNamespace . 'name'])) {
                    if (!in_array($param[$tasksNamespace . 'name'], $definedparams)) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" ' . $tasksNamespace .
                            'paramgroup> id "' . $param[$tasksNamespace . 'id'] .
                            '" parameter "' . $param[$tasksNamespace . 'name'] .
                            '" has not been previously defined');
                    }
                    if (!isset($param[$tasksNamespace . 'conditiontype'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" ' . $tasksNamespace .
                            'paramgroup> id "' . $param[$tasksNamespace . 'id'] .
                            '" must have a ' . $tasksNamespace .
                            'conditiontype> tag containing either "=", ' .
                            '"!=", or "preg_match"');
                    }
                    if (!in_array($param[$tasksNamespace . 'conditiontype'],
                          array('=', '!=', 'preg_match'))) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" ' . $tasksNamespace .
                            'paramgroup> id "' . $param[$tasksNamespace . 'id'] .
                            '" must have a ' . $tasksNamespace .
                            'conditiontype> tag containing either "=", ' .
                            '"!=", or "preg_match"');
                    }
                    if (!isset($param[$tasksNamespace . 'value'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" ' . $tasksNamespace .
                            'paramgroup> id "' . $param[$tasksNamespace . 'id'] .
                            '" must have a ' . $tasksNamespace .
                            'value> tag containing expected parameter value');
                    }
                }
                if (isset($param[$tasksNamespace . 'instructions'])) {
                    if (!is_string($param[$tasksNamespace . 'instructions'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" ' . $tasksNamespace .
                            'paramgroup> id "' . $param[$tasksNamespace . 'id'] .
                            '" ' . $tasksNamespace . 'instructions> must be simple text');
                    }
                }
                if (!isset($param[$tasksNamespace . 'param'])) {
                    continue; // <param> is no longer required
                }
                $subparams = $param[$tasksNamespace . 'param'];
                if (!is_array($subparams) || !isset($subparams[0])) {
                    $subparams = array($subparams);
                }
                foreach ($subparams as $subparam) {
                    if (!isset($subparam[$tasksNamespace . 'name'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" parameter for ' .
                            $tasksNamespace . 'paramgroup> id "' .
                            $param[$tasksNamespace . 'id'] . '" must have ' .
                            'a ' . $tasksNamespace . 'name> tag');
                    }
                    if (!preg_match('/[a-zA-Z0-9]+/',
                          $subparam[$tasksNamespace . 'name'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" parameter "' .
                            $subparam[$tasksNamespace . 'name'] .
                            '" for ' . $tasksNamespace . 'paramgroup> id "' .
                            $param[$tasksNamespace . 'id'] .
                            '" is not a valid name.  Must contain only alphanumeric characters');
                    }
                    if (!isset($subparam[$tasksNamespace . 'prompt'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" parameter "' .
                            $subparam[$tasksNamespace . 'name'] .
                            '" for ' . $tasksNamespace . 'paramgroup> id "' .
                            $param[$tasksNamespace . 'id'] .
                            '" must have a ' . $tasksNamespace . 'prompt> tag');
                    }
                    if (!isset($subparam[$tasksNamespace . 'type'])) {
                        return array(PEAR_TASK_ERROR_INVALID, 'Post-install script "' .
                            $fileXml['name'] . '" parameter "' .
                            $subparam[$tasksNamespace . 'name'] .
                            '" for ' . $tasksNamespace . 'paramgroup> id "' .
                            $param[$tasksNamespace . 'id'] .
                            '" must have a ' . $tasksNamespace . 'type> tag');
                    }
                    $definedparams[] = $param[$tasksNamespace . 'id'] . '::' .
                    $subparam[$tasksNamespace . 'name'];
                }
            }
        }
        return true;
    }
Validate the raw xml at parsing-time.

This also attempts to validate the script to make sure it meets the criteria
for a post-install script
@param PEAR_PackageFile_v2
@param array The XML contents of the <postinstallscript> tag
@param PEAR_Config
@param array the entire parsed <file> tag
@static