Unable to create migration: The namespace with name "public" already exists.

[VictorKrasnov]

fix: unable to make migration on Postgres

Error message "The namespace with name "public" already exists." on d:m:diff or migration:make fixed.

[greg0ire]

Sorry but… what was wrong with this message, and under which circumstances does it occur?

[VictorKrasnov]

I updated Symfony 6.4 to 7.2 and Doctrine 2 to 3.3 yesterday. After this I tried to run commands like make:migration or doctrine:migration:diff. Any attempt to create migration ended with error: "The namespace with name "public" already exists". I debugged your code and found that a value of variable $defaultNamespace is setting with schema name. So as I understood, maybe mistaken, you tried to use schema name for namespace name. I don't know what is namespace in PostgreSQL, but changes that I published here made my application work.

Sorry, but I can't make some reproduction for you, my project is private and not small at all. However, if necessary, I can share, for example, my doctrine configuration.

[greg0ire]

This was introduced very recently, in #1463 cc @morozov maybe you will understand what's going on?

[VictorKrasnov]

And one more thing. I also tried to figure out my issue another way. I found the table "shemata" in the database "information_shema". I found record here with shema "public", and I checked that schema owner is the same user, that is used in Symfony. So, I had schema public already, but Doctrine tried to create another one when I tried to create some new migration.

[greg0ire]

Regarding the confusion about "schema", I recommend you read this: https://github.com/doctrine/dbal/blob/c91166a91b8639a1d7bfe0f88bca0273bdbe9d2d/src/Schema/Schema.php#L21-L44

[greg0ire]

Also, I think this is a known issue. I recommend you upgrade to DBAL 4

You are already using DBAL 4, right?

[VictorKrasnov]

Thanks for your explanation of namespaces in doctrine. It's clear, so my pull request seems wrong.

My doctrine versions are:

# composer show doctrine/*
doctrine/cache                      2.2.0  PHP Doctrine Cache library is a popular cache implementation that supports many different drivers such as redis, memcache, apc, mongodb and others.
doctrine/collections                2.2.2  PHP Doctrine Collections library that adds additional functionality on top of PHP arrays.
doctrine/common                     3.4.5  PHP Doctrine Common project is a library that provides additional functionality that other Doctrine projects depend on such as better reflection s...
doctrine/dbal                       4.2.1  Powerful PHP database abstraction layer (DBAL) with many features for database schema introspection and management.
doctrine/deprecations               1.1.4  A small layer on top of trigger_error(E_USER_DEPRECATED) or PSR-3 logging with options to disable all deprecations or selectively for packages.
doctrine/doctrine-bundle            2.13.1 Symfony DoctrineBundle
doctrine/doctrine-migrations-bundle 3.3.1  Symfony DoctrineMigrationsBundle
doctrine/event-manager              2.0.1  The Doctrine Event Manager is a simple PHP event system that was built to be used with the various Doctrine projects.
doctrine/inflector                  2.0.10 PHP Doctrine Inflector is a small library that can perform string manipulations with regard to upper/lowercase and singular/plural forms of words.
doctrine/instantiator               2.0.0  A small, lightweight utility to instantiate objects in PHP without invoking their constructors
doctrine/lexer                      3.0.1  PHP Doctrine Lexer parser library that can be used in Top-Down, Recursive Descent Parsers.
doctrine/migrations                 3.8.2  PHP Doctrine Migrations project offer additional functionality on top of the database abstraction layer (DBAL) for versioning your database schema...
doctrine/orm                        3.3.0  Object-Relational-Mapper for PHP
doctrine/persistence                3.4.0  The Doctrine Persistence project is a set of shared interfaces and functionality that the different Doctrine object mappers share.
doctrine/sql-formatter              1.5.1  a PHP SQL highlighting library

[greg0ire]

The DBAL includes all existing namespaces into the introspected schema, including the default ones like public for PostgreSQL.

If you are getting that error, then it must mean that in your case, public is not included in the introspected schema for some reason. It should be present in both $fromSchema and $toSchema, but right now, it only seems to be included in $toSchema.

[VictorKrasnov]

[greg0ire]

Oh I see, this isn't an SQL error, this is a DBAL exception because you already have public inside $toSchema->namespaces 🤔

Reading the code, It seems we expect to either have _name set to 'public' or namespaces set to ['public'], but not both 🤔

[greg0ire]

Do any of your ORM mapping files/configuration mention public?

[VictorKrasnov]

No, I can't find anything.

[greg0ire]

Well what you can do is start a brand new project with all the latest libraries, and using Postgres, and test that you don't have the issue, since people at #1415 (comment) say it works for them.

If you don't reproduce the issue, use your debugger on the new project to see how exactly the variables differ from what you have in your project, in particular $toSchema.

You could also start from https://github.com/greg0ire/sample-pg-app

[VictorKrasnov]

OK, thanks for your help. I'll try to do that a little later.

[derrabus]

Can we please find a meaningful title for this PR? Thanks.

[VictorKrasnov]

Can we please find a meaningful title for this PR? Thanks.

Done.

[morozov]

This doesn't look right. The schema is the namespace for its tables. The schema itself cannot be associated with a namespace (only tables, views and sequences can). Currently it's possible to call getNamespaceName() on any AbstractAsset (which is a design flaw) but in DBAL 5, it will be possible only with the objects mentioned earlier.

The only situation in which currently a schema can be associated with a namespace is when its name contains a dot and the name isn't quoted (which is also a flaw and shouldn't be allowed).