Check PHP PDO attribute behavior against documented behavior

<?php

$db = new PDO('mysql:dbname=test;host=localhost', 'root', 'myself');

$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$documentedAs = array(
    'ATTR_AUTOCOMMIT' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_PREFETCH' => array(
        'type' => 'integer',
        'notAlwaysPresent' => 'true',
    ),
    'ATTR_TIMEOUT' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_ERRMODE' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_SERVER_VERSION' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_CLIENT_VERSION' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_SERVER_INFO' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_CONNECTION_STATUS' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_CASE' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_CURSOR_NAME' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_CURSOR' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_DRIVER_NAME' => array(
        'type' => 'string',
        'notAlwaysPresent' => false,
    ),
    'ATTR_ORACLE_NULLS' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_PERSISTENT' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_STATEMENT_CLASS' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_FETCH_CATALOG_NAMES' => array(
        'type' => 'integer',
        'notAlwaysPresent' => true,
    ),
    'ATTR_FETCH_TABLE_NAMES' => array(
        'type' => 'integer',
        'notAlwaysPresent' => true,
    ),
    'ATTR_STRINGIFY_FETCHES' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_MAX_COLUMN_LEN' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_DEFAULT_FETCH_MODE' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'ATTR_EMULATE_PREPARES' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_USE_BUFFERED_QUERY' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_LOCAL_INFILE' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_INIT_COMMAND' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_READ_DEFAULT_FILE' => array(
        'type' => 'integer',
        'notAlwaysPresent' => true,
    ),
    'MYSQL_ATTR_READ_DEFAULT_GROUP' => array(
        'type' => 'integer',
        'notAlwaysPresent' => true,
    ),
    'MYSQL_ATTR_MAX_BUFFER_SIZE' => array(
        'type' => 'integer',
        'notAlwaysPresent' => true,
    ),
    'MYSQL_ATTR_DIRECT_QUERY' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_FOUND_ROWS' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_IGNORE_SPACE' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_COMPRESS' => array(
        'type' => 'integer',
        'notAlwaysPresent' => true,
    ),
    'MYSQL_ATTR_SSL_CA' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_SSL_CAPATH' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_SSL_CERT' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_CIPHER' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
    'MYSQL_ATTR_KEY' => array(
        'type' => 'integer',
        'notAlwaysPresent' => false,
    ),
);

$reflection = new ReflectionClass($db);

function writeNotice($str)
{
    static $nr = 1;
    echo "#{$nr} {$str}" . PHP_EOL;
    $nr++;
}

// documented but not defined as class constant:
foreach (array_diff(array_keys($documentedAs), array_keys($reflection->getConstants())) as $documentedButNotExisting) {
    if (!$documentedAs[$documentedButNotExisting]['notAlwaysPresent']) {
        writeNotice("{$documentedButNotExisting} is in the documentation but not defined as a class constant.");
    }
}

foreach ($reflection->getConstants() as $constantName => $constant) {
    if (strpos($constantName, 'ATTR') !== false) {
        // defined but not documented:
        if (!isset($documentedAs[$constantName])) {
            writeNotice("{$constantName} is defined as a class constant but is not in the documentation.");
            continue;
        }
        try {
            $attrValue = $db->getAttribute($constant);

            // documented but with wrong type
            $actualType = gettype($attrValue);
            $documentedType = $documentedAs[$constantName]['type'];
            if ($actualType !== $documentedType) {
                writeNotice("{$constantName} has type {$actualType} but is documented as {$documentedType}.");
            }
        }
        catch (PDOException $e) {
            // documented, defined as class constant but not retrievable with getAttribute()
            if (!$documentedAs[$constantName]['notAlwaysPresent']) {
                writeNotice("{$constantName} could not be retrieved but the documentation makes it appear it is always present.");
            }
        }
    }
}