index.php has syntax error instead of graceful fail for < 5.3

I'm confused how this happens (but don't have PHP 5.2 handy to test). Stripped of code comments, install.php, for example, looks like this:

chdir('..');
define('DRUPAL_ROOT', getcwd());
define('MAINTENANCE_MODE', 'install');
if (version_compare(PHP_VERSION, '5.3.3') < 0) {
  print 'Your PHP installation is too old. Drupal requires at least PHP 5.3.3. See the <a href="http://drupal.org/requirements">system requirements</a> page for more information.';
  exit;
}

// Start the installer.
require_once DRUPAL_ROOT . '/core/includes/install.core.inc';
install_drupal();

There are no "use" statements in this file; those only happen once install.core.inc is loaded. So doesn't the script exit before there is ever a problem?

The use statement doesn't matter. As soon as we hit a namespaced class name instead, there will still be a parse error.

The only alternative would be to only use non-namespaced code in the installer, or portions of the installer, which strikes me as a foolish no-go. We syntax error on PHP 4. By the time Drupal 8 ships, PHP 5.3 will already be in security-only status. 5.2 will be dead dead dead.

(The PHP internals team is stepping up their release schedule, with plans for an actual schedule and scheduled deprecation of older releases rather than the long tail of support as in the past. See https://wiki.php.net/rfc/releaseprocess )

I say this is a won't fix.

The only way to bypass those syntax errors, I think, would be for install.php to be something like:

if (version_compare(...)) {
  include('real_install.inc');
  drupal_install();
}
else {
  // Print error message that doesn't require the theme system.
}

We may be able to get away with that for install and update, but not for index.php since that would be hit on every request.

Sorry, I garbled explaining Tim's testing. You get the "nice" error on update.php or install.php, but on 5.2 you get a syntax error before you can get redirected there, and on 5.3.2 (per timplunkett) you get a fatal. Who goes directly to install.php when they download Drupal for the first time? Not me. I just go to the folder where I put it.

On 5.2:

It's perhaps not quite as bad for upgrading since a lot of people are used to navigating to update.php and that's in all our instructions. However, for those that don't, their site is suddenly toast with no feedback. (As above.)

That said, I just meant to post an FYI; I wasn't thinking of it as a critical. But if we really want to give people feedback on the version issue when they try to install D8 with old PHP, we'd need to handle index.php too.

...It's perhaps not quite as bad for upgrading since a lot of people are used to navigating to update.php and that's in all our instructions. ...

I still think we should fix this to present meaningful errors to users in all possible cases. We shouldn't close it, but rather downgrade its critical status instead. This feels like "sweeping under the carpet" to me. It is a reproducible WTF so if it can be fixed, then we should fix it.

Yeah, I'd agree. Reopening at normal. Maybe we can't fix it in a sane way, but I don't see the point of having special code in install.php and update.php than 90% of users won't see because index.php blows up on them first.

Edit: Especially since the fatal error on 5.3.2 impacts Lucid. (https://wiki.ubuntu.com/LTS)

So I agree it would be nice to fix, but it might very well be impossible to without adding code to the critical path that we don't really want there.

I'm pretty sure index.php in Drupal 7 has this problem also (though I can't remember exactly which PHP versions it has it for, maybe only PHP 4 in which case it would be less serious than the problem here).

Patch to fix this for update.php: #1749790: PHP 5.3 detection fails on update

That looks like a huge chunk of the includes/update.core.inc just had to be re-written.

I'm going to vote we just won't-fix this issue again, esp. now that we're going all the way to 5.4. Any objections?

No objections, so closing.