MySQL fails when try to drop a primary index with Auto Increment

When an update of schema tries to drop a primary key with "auto increment" property (example : @ORM\GeneratedValue(strategy="AUTO")), the execution will fail : it say :
[Doctrine\DBAL\DBALException]
An exception occurred while executing 'ALTER TABLE odesadicola DROP PRIMARY KEY':

SQLSTATE[42000]: Syntax error or access violation: 1075 Incorrect table definition; there can be only one auto column and it must be defined as a key

Apparently, this error occurs because Doctrine try to execute a "drop primary key" on a table and the resulting column of old primary key will be "auto increment".

The answer is to remove "auto increment" attribut of primary key column juste before try to drop the primary key itself.