dbDelta fails with existing tables and indices

[sourcerer-mike]

Referring "wp-admin/includes/upgrade.php:2231" @WP 4.3.1

Take this Query:

CREATE TABLE wp_termmeta (
        meta_id bigint(20) NOT NULL AUTO_INCREMENT,
        term_id bigint(20) NOT NULL default 0,

        meta_key varchar(255) DEFAULT NULL,
        meta_value longtext DEFAULT NULL
    )

   UNIQUE KEY meta_id (meta_id)

Running it multiple times with dbDelta will fail in an invalid Query:

ALTER TABLE wp_termmeta ADD

It creates queries for indices. But as I debug the variable $indices looks like this:

$indices = array(
  1 => "",
  2 => "",
);

I don't know why it is "empty" but this might be a hotfix:

$indices = array_filter($indices);

[pento]

Hi there!

This isn't a valid CREATE TABLE statement - the UNIQUE KEY line needs to be inside the brackets.

dbDelta() also doesn't play nicely with blank lines - see wp-admin/includes/schema.php for examples of how to write dbDelta()-friendly table definitions.

dbDelta() is not intended to parse all possible table definitions, just the subset needed for WordPress tables. While we're open to expanding what it supports, of course, for standard table definitions, you need to adhere to the formats it supports.