0777 directory permissions, why do we need that?

[kartikgits]

In src/Cache/FilesystemCache.php write function,
we have mkdir($dir, 0777, true)
Why do we need to give full permissions to groups and others? We're using twig for some time now and haven't been able to get this. That doesn't seem secure for production systems.

    public function write(string $key, string $content): void
    {
        $dir = \dirname($key);
        if (!is_dir($dir)) {
            if (false === @mkdir($dir, 0777, true)) {
                clearstatcache(true, $dir);
                if (!is_dir($dir)) {
                    throw new \RuntimeException(\sprintf('Unable to create the cache directory (%s).', $dir));
                }
            }
        } elseif (!is_writable($dir)) {
            throw new \RuntimeException(\sprintf('Unable to write in the cache directory (%s).', $dir));
        }

        $tmpFile = tempnam($dir, basename($key));
        if (false !== @file_put_contents($tmpFile, $content) && @rename($tmpFile, $key)) {
            @chmod($key, 0666 & ~umask());

            if (self::FORCE_BYTECODE_INVALIDATION == ($this->options & self::FORCE_BYTECODE_INVALIDATION)) {
                // Compile cached file into bytecode cache
                if (\function_exists('opcache_invalidate') && filter_var(\ini_get('opcache.enable'), \FILTER_VALIDATE_BOOLEAN)) {
                    @opcache_invalidate($key, true);
                } elseif (\function_exists('apc_compile_file')) {
                    apc_compile_file($key);
                }
            }

            return;
        }

        throw new \RuntimeException(\sprintf('Failed to write cache file "%s".', $key));
    }

[stof]

mkdir($dir, 0777, true) does not give full permission on the folder.
The actual permissions of the folder will depend on the umask being configured (which is often 0022), which is the right thing to do (see also the permissions of the file itself where we use chmod($key, 0666 & ~umask()) because chmod does not automatically applies the umask)

[kartikgits]

Thanks, I get that now.