pest/src/Plugins/Tia/TableExtractor.php

<?php

declare(strict_types=1);

namespace Pest\Plugins\Tia;

/**
 * Extracts table names from SQL statements and migration PHP sources.
 *
 * Two callers, two methods:
 *
 *   - `fromSql()` runs against query strings Laravel's `DB::listen`
 *     hands us at record time. We only look at DML (`SELECT`, `INSERT`,
 *     `UPDATE`, `DELETE`) because DDL emitted by `RefreshDatabase` in
 *     `setUp()` is noise — we don't want every test to end up linked
 *     to every migration's `CREATE TABLE`.
 *   - `fromMigrationSource()` reads a migration file on disk at
 *     replay time and pulls table names out of `Schema::` calls.
 *     Used in two places:
 *       1. For every migration file reported as changed — what
 *          tables does the current version of this file touch?
 *       2. For brand-new migration files that weren't in the graph
 *          yet, so we never had a chance to observe their DDL.
 *
 * Regex isn't a parser. CTEs, subqueries, and raw `DB::statement()`
 * that reference tables only inside exotic syntax can slip through.
 * The direction of that error is under-attribution (a table the test
 * genuinely touches but we missed), so the safety net is to keep the
 * broad `database/migrations/**` watch pattern as a last resort for
 * files that produce an empty extraction.
 *
 * @internal
 */
final class TableExtractor
{
    /**
     * DML prefixes we accept. DDL (`CREATE`, `ALTER`, `DROP`,
     * `TRUNCATE`, `RENAME`) is deliberately excluded — those come
     * from migrations fired by `RefreshDatabase`, and capturing them
     * here would attribute every migration table to every test.
     */
    private const array DML_PREFIXES = ['select', 'insert', 'update', 'delete'];

    /**
     * @return list<string> Sorted, deduped table names referenced by the
     *                      SQL statement. Empty when the statement is
     *                      DDL, empty, or unparseable.
     */
    public static function fromSql(string $sql): array
    {
        $trimmed = ltrim($sql);

        if ($trimmed === '') {
            return [];
        }

        $prefix = strtolower(substr($trimmed, 0, 6));

        $matched = false;
        foreach (self::DML_PREFIXES as $dml) {
            if (str_starts_with($prefix, $dml)) {
                $matched = true;

                break;
            }
        }

        if (! $matched) {
            return [];
        }

        // Match `from`, `into`, `update`, `join` and capture the
        // following identifier, tolerating the common quoting
        // styles: "double", `back`, [bracket], or bare.
        $pattern = '/(?:\bfrom|\binto|\bupdate|\bjoin)\s+(?:"([^"]+)"|`([^`]+)`|\[([^\]]+)\]|(\w+))/i';

        if (preg_match_all($pattern, $sql, $matches) === false) {
            return [];
        }

        $tables = [];

        for ($i = 0, $n = count($matches[0]); $i < $n; $i++) {
            $name = $matches[1][$i] !== ''
                ? $matches[1][$i]
                : ($matches[2][$i] !== ''
                    ? $matches[2][$i]
                    : ($matches[3][$i] !== ''
                        ? $matches[3][$i]
                        : $matches[4][$i]));
            if ($name === '') {
                continue;
            }
            if (self::isSchemaMeta($name)) {
                continue;
            }

            $tables[strtolower($name)] = true;
        }

        $out = array_keys($tables);
        sort($out);

        return $out;
    }

    /**
     * @return list<string> Table names referenced by `Schema::` calls
     *                      in the given migration file contents. Empty
     *                      when nothing matches — callers treat that
     *                      as "fall back to the broad watch pattern".
     */
    public static function fromMigrationSource(string $php): array
    {
        $pattern = '/Schema::\s*(?:create|table|drop|dropIfExists|dropColumns|rename)\s*\(\s*[\'"]([^\'"]+)[\'"](?:\s*,\s*[\'"]([^\'"]+)[\'"])?/';

        if (preg_match_all($pattern, $php, $matches) === false) {
            return [];
        }

        $tables = [];

        foreach ($matches[1] as $i => $primary) {
            // Group 1 always captures at least one char per the regex.
            $tables[strtolower($primary)] = true;

            // Group 2 (`Schema::rename('old', 'new')`) is optional and
            // absent from non-rename matches.
            $secondary = $matches[2][$i] ?? '';
            if ($secondary !== '') {
                $tables[strtolower($secondary)] = true;
            }
        }

        $out = array_keys($tables);
        sort($out);

        return $out;
    }

    /**
     * Filters out driver-internal tables that show up as DB::listen
     * targets without representing user schema: SQLite's master
     * catalogue, Laravel's own `migrations` metadata.
     */
    private static function isSchemaMeta(string $name): bool
    {
        $lower = strtolower($name);

        return in_array($lower, ['sqlite_master', 'sqlite_sequence', 'migrations'], true)
            || str_starts_with($lower, 'pg_')
            || str_starts_with($lower, 'information_schema');
    }
}