Gii can not generate model from mysql tables

[mxmorozov]

When I try to use Model Generator
PHP Warning – yii\base\ErrorException

1. in .../vendor/yiisoft/yii2-gii/src/generators/model/Generator.php at line 523
   array_flip(): Can only flip STRING and INTEGER values!

mysql 8
php 7.3
Yii 2.0.17
centos 7

[alex-code]

Can you show your table schema including relations as the error is in the section that builds relations.

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[mxmorozov]

It seems any mysql foreign key will be sufficient to get error.
For example

CREATE TABLE `a` (
  `id` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8

CREATE TABLE `b` (
  `id` int(11) NOT NULL,
  `a_id` int(11) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `a_id` (`a_id`),
  CONSTRAINT `b_ibfk_1` FOREIGN KEY (`a_id`) REFERENCES `a` (`id`) ON DELETE RESTRICT ON UPDATE RESTRICT
) ENGINE=InnoDB DEFAULT CHARSET=utf8"

Error on generating models for both tables

[mxmorozov]

I tested further and model generator fails even without foreign keys. Even with "Generate Relations from Current Schema" disabled. May be PHP 7.3 is the cause?

[samdark]

Can you downgrade and check it?

[mxmorozov]

I found mysql scheme pattern that causes error

CREATE TABLE `a` (
  `id` int(11) NOT NULL,
  PRIMARY KEY (`id`)
)

CREATE TABLE `b` (
  `id` int(11) NOT NULL,
  `a_id` int(11) NOT NULL,
  `some_field` varchar(255) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `a_id` (`a_id`, `some_field`),
  CONSTRAINT `a_id` FOREIGN KEY (`a_id`) REFERENCES `a` (`id`) ON DELETE RESTRICT ON UPDATE RESTRICT
)

When you have a table like 'b' in your db, model generator will fail on every table because it scans all tables relations.
Also if rename unique key or foreign key - error will gone. Seems identical names (a_id) are a problem.