Install script returns a blank page for PHP4, PHP 5.1 (should display *something* instead)

Yeah, Drupal 7 requires PHP 5.2 (see http://drupal.org/requirements), so that's probably it.

It's a bit unfortunate that we get a white screen in that case though. For someone running PHP 4, that might be unavoidable, but for PHP 5.1 it seems like it would be nice if we could at least get them to the requirements page (which is automatically set up to print an error message if your version of PHP isn't new enough).

When you say there were no errors in the log files, do you mean the PHP log files? Was error logging definitely turned on for this server? It seems like there should be some kind of error message generated in this case - if possible to check, can you see if it was similar to the ones reported in these issues for PHP 4?
#668136: Cant reach the requirements page without php5 enabled
#315901: Add server capabilities check to installation/upgrade tasks

I'm running Apache/2.1.8? (CentOS 5.4), MySQL 5.0.77, PHP 5.3.2 and have been unable to resolve this issue. Can't get phpmyadmin or drupal 7 to show anything but a blank page, phpmyadmin show's an error page telling me it requires php 5.2 or higher?

@uraxs, if you are seeing that issue with phpmyadmin as well, then it's likely a problem with your server, not Drupal.

Let's keep this issue about PHP 5.1 or similar - We don't expect Drupal 7 to work with that version of PHP, but ideally we want to get people to the requirements screen so that we can tell them that.

@david, I had php 5.1.77 installed and updated to php5.3.2 and restarted the server which resolved many of the issues. Now I'm able to pull up the install.php page but when I go to check the configuration after I select a language I get a blank page.

UPDATE: I downloaded a fresh copy of D7 and installed it on another IP on the same VPS with complete success. I then uploaded that fresh version and replaced the one on the IP that had the issues. Now, everything is working just dandy on CentOS 5.4/ Apache 2.2.3 with PHP 5.3.2 and MYSQL 5.0.77 and seems to very stable. Thanks!

I don't think the original bug here was ever fixed. It was reported again at #920222: Add proper version check to install_drupal and abort if PHP version < 5.2.0, but I'm reopening this instead since there was more discussion here.

#944518: Browseing install.php is blank page, nothing. was recently filed and I think is a duplicate of this one.

It would be nice to get this fixed. There are a number of people out there who still run PHP 5.1.

This keeps coming up (just marked #944518: Browseing install.php is blank page, nothing. as a duplicate), so increasing priority to major. It'd be nice if we could do something here other than a blank white page for folks who don't meet the system requirements.

In addition to PHP 5.1 displaying a WSOD (what's the root cause of that?), PHP 4 fails with a parse error... in bootstrap.inc.

We have no choice other to add a catch-all version control directly in install.php, update.php, and maybe also index.php.

Ok, I decided to party like it was 2006 and install MAMP 1.4.1 which gives me PHP 5.1.6 and MySQL 5.0.19.

The actual errors you get behind the scenes is 7,000,000 of these:

[20-Oct-2010 23:31:03] PHP Notice:  Use of undefined constant E_RECOVERABLE_ERROR - assumed 'E_RECOVERABLE_ERROR' in /Applications/MAMP/htdocs/drupal-7.x-dev/includes/errors.inc on line 43
[20-Oct-2010 23:31:03] PHP Notice:  Use of undefined constant E_RECOVERABLE_ERROR - assumed 'E_RECOVERABLE_ERROR' in /Applications/MAMP/htdocs/drupal-7.x-dev/includes/errors.inc on line 87

followed by:

[20-Oct-2010 23:31:04] PHP Fatal error:  Call to undefined function array_fill_keys() in /Applications/MAMP/htdocs/drupal-7.x-dev/includes/common.inc on line 2905

I stuck:

debug_print_backtrace();exit;

just above that line (per catch)

and I get:

#0 drupal_get_css() called at [/Applications/MAMP/htdocs/drupal-7.x-dev/includes/theme.inc:2481]
#1 template_process_maintenance_page(Array([snip])) called at [/Applications/MAMP/htdocs/drupal-7.x-dev/includes/theme.inc:845]
#2 theme(maintenance_page, Array ([snip]) called at [/Applications/MAMP/htdocs/drupal-7.x-dev/includes/theme.maintenance.inc:145]
#3 theme_install_page(Array ([snip])) called at [/Applications/MAMP/htdocs/drupal-7.x-dev/includes/theme.inc:881]
#4 theme(install_page, Array ([snip]) called at [/Applications/MAMP/htdocs/drupal-7.x-dev/includes/install.core.inc:703]
#5 install_display_output(Array([snip]) called at [/Applications/MAMP/htdocs/drupal-7.x-dev/includes/install.core.inc:104]
#6 install_drupal() called at [/Applications/MAMP/htdocs/drupal-7.x-dev/install.php:21] 

Since I'm correctly forwarded off from index.php to install.php (yay!), I don't see a reason we need to hack index.php (and I don't think I'd support that under any circumstances anyway). chx is working on a patch.

And since MAMP 1.4.1 *also* ships with PHP 4.4.4, here's the results on that one.

[20-Oct-2010 23:48:00] PHP Parse error:  syntax error, unexpected '{' in /Applications/MAMP/htdocs/drupal-7.x-dev/includes/bootstrap.inc on line 680

Thanks to try { .. }

However, since it's not 2006 anymore and it's now 2010, I'm perfectly happy to tell PHP 4 users to go fly a kite (or to pass that message along to their absolutely craptastical hosts).

Something like this: http://paste.pocoo.org/show/278277/ :P

This is hitting a lot of people, and I'd like people who test beta2 to find *new* bugs, so tagging as a beta blocker.

Added version check at top if install.php Could not re-use DRUPAL_MINIMUM_PHP without including bootstrap. Thats worse than just duplicating "5.2.4".

Now checking for 5.2.4 and not 5.2.0

Couple adjustments, then this seems good to go:

1. Let's comment why we're doing such a horrible hack. Something to the effect of "Exit early if running an incompatible PHP version to avoid fatal errors."
2. Let's throw in a link to http://drupal.org/requirements. They obviously haven't read them if they are getting this error.
3. Single quotes not double quotes on the string. ;)

I am also curious what happens on update.php, but I couldn't get my relic MAMP to fire today, so I figure we can tackle that in another issue. Chances are people are going to install D7 from scratch first to get acquainted with it before they upgrade, and will discover system incompatibilities then, so it might be a non-issue.

Refined as suggested.

Why not just copy-paste the same wording we already have in system_requirements()? Someone already took the time to perfect the phrasing there :)

Also not sure if we really need to check all the way up to 5.2.4? (If someone has e.g. 5.2.1, I'm pretty sure they'd be able to make their way to the requirements page and see the message there.)

On the other hand, maybe better safe than sorry, and probably no one runs a version like 5.2.1 anymore anyway :) Either is OK.

One more quick reroll. Can't believe I didn't notice it before, but this code shouldn't be at the very top of the file (above even the @file declaration), seems like that violates style guidelines. We can put it at the part right before the main code actually runs.

OK, but WTF is a PHP installation?

Ok, great. Committed to HEAD.

I agree "PHP installation" is a bit awkward, but not sure it's worth breaking strings for, and consistency is the name of the game here.