Installer doesn't start on fresh installation [ver. 5.5.2]

[garubi]

doing a fresh installation of WordPress ver 5.5.2
the classic "installer wizard" doesn't start and WP show the following message

One or more database tables are unavailable. The database may need to be repaired.

Being the first step of a fresh install obviously the DB has nothing to do with the problem, since at this step WP doesn't know anything about the DB.

Server info:

PHP Version 7.4.7
mysql  Ver 14.14 Distrib 5.7.32, for Linux (x86_64) using  EditLine wrapper
nginx version: nginx/1.15.8

the server hosts many other WP sites, but this is the first fresh installation of the new 5.5.2, so it's probably related to some regression introduced with the new release

[garubi]

Googling for the same problem, it looks like the problem is in

 wp-includes/functions.php at line 1756

As I found on this support forum post(​https://wordpress.org/support/topic/wordpress-installer-error/#post-13600170), this code checks if the tables in db already exist, and for some reason on some environments get a false positive:

<?php
    $described_table = $wpdb->get_results( "DESCRIBE $table;" );
    if ( is_array( $described_table ) && count( $described_table ) === 0 ) {
        continue;
    }

if you replace that with:

<?php
if ( ! $wpdb->get_results( "DESCRIBE $table;" ) ) {
    continue;
}

the installer works just fine.

[mukesh27]

Hi there!

Yes. I'm facing same issue for fresh installation of WordPress 5.5.2

[mukesh27]

Patch that fixed the issue

[garubi]

Hi,
I confirm that the patch fixes the issue on our servers

[garubi]

#51673 was marked as a duplicate.

[desrosj]

Thank you for the report, @garubi!

Since this was a security fix, simply reverting the code as in 51676.patch​ is not an option. The team is investigating and will update when there are findings!

[xknown]

In attachment:51676.2.diff​, is_blog_installed doesn't longer return errors if we don't have a valid database connection.

[johnbillion]

FYI I am seeing this error locally, here's the value of those variables:

• $described_table is null
• $wpdb->errors is null
• $wpdb->ready is boolean false
• $table is string users, which is the first table returned by $wpdb->tables()

PHP 7.3
MySQL MariaDB 10.4

[metalandcoffee]

I tested the 52676.diff. I’ve tested it with fresh installs of 5.5.2, 5.4.3, 5.3.5, 5.2.8 and 5.1.7. All were successful.

I did not need to test 5.0.11 and 4.9.16 again because they were not broken. I have not tested the earlier installs yet. Please let me know if you’d like me to continue to go back to 3.7.

PHP version 7.4
MariaDB Version: 10.3.25

[davidbaumwald]

Discussed with @johnbillion and the latest patch would probably benefit from some extra parentheses.

[xknown]

Replying to davidbaumwald:

Discussed with @johnbillion and the latest patch would probably benefit from some extra parentheses.

Thanks, I updated the patch in attachment:51676.3.diff​.

[xknown]

Replying to metalandcoffee:

I tested the 52676.diff. I’ve tested it with fresh installs of 5.5.2, 5.4.3, 5.3.5, 5.2.8 and 5.1.7. All were successful.

I did not need to test 5.0.11 and 4.9.16 again because they were not broken. I have not tested the earlier installs yet. Please let me know if you’d like me to continue to go back to 3.7.

PHP version 4.0
MariaDB Version: 10.3.25

Can you please continue testing the patch with older releases too? I am also doing the same, having some more eyes/tests on this patch is better.

[mukesh27]

51676.3.diff​ patch working fine for me in fresh installation.

PHP version: 7.3.9
MariaDB: 10.4.6

Can we change condition like below

if (
	( ! $described_table && empty( $wpdb->last_error ) ) ||
	( is_array( $described_table ) && 0 === count( $described_table ) )
) {

[metalandcoffee]

Just confirmed that the 4.8.15, 4.7.19 and 4.6.20 installs did not need to be tested against this patch because they did not appear as broken for me.

PHP version 7.4
MariaDB Version: 10.3.25

[metalandcoffee]

Just a heads up from testing older WP versions...

I’m running into the following fatal error when I do fresh installs (via zip file download directly from the ​https://wordpress.org/download/releases/) for 4.0.32, 4.1.32, 4.2.29, 4.3.54, and 4.4.24.

Fatal error: Call to undefined function wp_installing() in .../wp-includes/update.php on line 640

PHP version: 5.6
MariaDB Version: 10.3.25

[whyisjake]

In 49452:

Upgrade/Install: During the install process, add additional checking for exising tables.

If reinstalling WordPress, there is a condition where tables would exist in the database. Ensures that when that is the case, the install process can carry along without issue.

Fixes #51676.

Props xknown, garubi, mukesh27, desrosj, johnbillion, metalandcoffee, davidbaumwald, whyisjake.

[whyisjake]

In 49453:

Upgrade/Install: During the install process, add additional checking for exising tables.

This commit brings the changes in [49452] to the 5.5 branch.

If reinstalling WordPress, there is a condition where tables would exist in the database. Ensures that when that is the case, the install process can carry along without issue.

Fixes #51676.

Props xknown, garubi, mukesh27, desrosj, johnbillion, metalandcoffee, davidbaumwald, whyisjake.

[whyisjake]

In 49454:

Upgrade/Install: During the install process, add additional checking for exising tables.

This commit brings the changes in [49452] to the 5.4 branch.

If reinstalling WordPress, there is a condition where tables would exist in the database. Ensures that when that is the case, the install process can carry along without issue.

Fixes #51676.

Props xknown, garubi, mukesh27, desrosj, johnbillion, metalandcoffee, davidbaumwald, whyisjake.

[whyisjake]

In 49455:

Upgrade/Install: During the install process, add additional checking for exising tables.

This commit brings the changes in [49452] to the 5.3 branch.

If reinstalling WordPress, there is a condition where tables would exist in the database. Ensures that$

Fixes #51676.

Props xknown, garubi, mukesh27, desrosj, johnbillion, metalandcoffee, davidbaumwald, whyisjake.

[whyisjake]

In 49456:

Upgrade/Install: During the install process, add additional checking for exising tables.

This commit brings the changes in [49452] to the 5.2 branch.

If reinstalling WordPress, there is a condition where tables would exist in the database. Ensures that$

Fixes #51676.

Props xknown, garubi, mukesh27, desrosj, johnbillion, metalandcoffee, davidbaumwald, whyisjake.

[whyisjake]

In 49457:

Upgrade/Install: During the install process, add additional checking for exising tables.

This commit brings the changes in [49452] to the 5.1 branch.

If reinstalling WordPress, there is a condition where tables would exist in the database. Ensures that$

Fixes #51676.

Props xknown, garubi, mukesh27, desrosj, johnbillion, metalandcoffee, davidbaumwald, whyisjake.