What causes "Cannot open bootstrap script "%s"" in sebastianbergmann/phpunit?

Create the missing file — usually by running composer install for vendor/autoload.php.

sebastianbergmann/phpunit · error · BootstrapScriptDoesNotExistException

Cannot open bootstrap script "%s"

Error message

Cannot open bootstrap script "%s"

What it means

BootstrapLoader::load() (via handle(), driven by the bootstrap attribute in phpunit.xml or --bootstrap on the CLI) first checks is_readable($filename); when that fails it throws BootstrapScriptDoesNotExistException('Cannot open bootstrap script "%s"'). The bootstrap file must exist and be readable before PHPUnit will include it.

Source

Thrown at src/TextUI/Configuration/BootstrapLoader.php:57

            if ($configuration->includeTestSuites() !== [] && !in_array($testSuiteName, $configuration->includeTestSuites(), true)) {
                continue;
            }

            if ($configuration->excludeTestSuites() !== [] && in_array($testSuiteName, $configuration->excludeTestSuites(), true)) {
                continue;
            }

            $this->load($bootstrapForTestSuite);
        }
    }

    /**
     * @param non-empty-string $filename
     */
    private function load(string $filename): void
    {
        if (!is_readable($filename)) {
            throw new BootstrapScriptDoesNotExistException($filename);
        }

        try {
            include_once $filename;
        } catch (Throwable $t) {
            $message = sprintf(
                'Error in bootstrap script: %s:%s%s%s%s',
                $t::class,
                PHP_EOL,
                $t->getMessage(),
                PHP_EOL,
                $t->getTraceAsString(),
            );

            while (($t = $t->getPrevious()) !== null) {
                $message .= sprintf(
                    '%s%sPrevious error: %s:%s%s%s%s',
                    PHP_EOL,

View on GitHub (pinned to f123cdb2a2)

Solutions

Create the missing file — usually by running composer install for vendor/autoload.php.
Fix the bootstrap path in phpunit.xml/--bootstrap; relative paths resolve against the CWD, so prefer a path relative to the configuration file.
Make the file readable by the PHP process if permissions are the issue.

Example fix

# before
composer dump-coverage 2>/dev/null; phpunit --bootstrap vendor/autoload.php tests
# => Cannot open bootstrap script "vendor/autoload.php"

# after
composer install
phpunit --bootstrap vendor/autoload.php tests

Defensive patterns

Strategy: validation

Validate before calling

$bootstrap = 'vendor/autoload.php';

if (!is_readable($bootstrap)) {
    throw new RuntimeException(
        "Bootstrap '{$bootstrap}' missing or unreadable; run 'composer install' first"
    );
}

// only then hand off to phpunit / BootstrapLoader

Prevention

Make 'composer install' (or the script that creates the bootstrap) a mandatory CI step before phpunit.
Reference the bootstrap relative to the phpunit.xml location, not the CWD.
Add a smoke check (is_readable) in CI wrapper scripts to fail with a clear message.

When it happens

Trigger: Configuring bootstrap="vendor/autoload.php" (or --bootstrap) when the file is missing — e.g. composer install has not run — or exists but is not readable by the PHP process.

Common situations: Fresh clones without 'composer install'; bootstrap path relative to the CWD while phpunit runs from another directory; path typos in phpunit.xml; permission problems in containers/CI.

Related errors

AI-assisted analysis of sebastianbergmann/phpunit@f123cdb2a2 (2026-08-23). Data as JSON: /api/errors/f424621afbfb5b47. Report an issue: GitHub.