A non-empty PSR-4 prefix must end with a namespace separator

Question

I'm trying to setup PSR-4 with Composer but I'm just getting A non-empty PSR-4 prefix must end with a namespace separator.

My autoload in my composer.json looks like this:

"autoload": {
    "psr-4": {
        "Acme\\models" : "app/models"
    }
},

app/models is empty.

What am I doing wrong? How can I fix this?

Hydrocephalus

Answer 1

Someone made a comment but removed it. He mentioned I was missing \\ at the end of Acme\\models. Acme\\models\\ will get rid of the message and work as it should.

Hydrocephalus

Yes, PSR-4 requires the trailing slash. (well double since it needs to be escaped) – Disparity

I must say this is not only a stupid requirement, the spec also makes it extremely clear that this is the case. Hence the reason I show up here for a very basic issue. – Parturition

After using this answer, I also found that composer validate also gives you a good indication of what's wrong. – Gassman

this cause issues when using repository type path, relative, symlinked, as it seems it tries to somehow recreate symlink just after this operation and has obsolete or cached composer.json – Drawback

I did this and still got the same error, should I remove the vendor or clear some cache? – Ivatts

For anyone using symlinked, you should delete the symlinked folder before trying again. – Ivatts

Answer 2

As others said PSR-4 requires the trailing slash

Though I had to convert / to \\ in Windows (should work fine on Linux):

    "autoload": {
        "psr-4": {
            "App\\": "src/"
        }
    },
    "autoload-dev": {
        "psr-4": {
            "App\\Tests\\": "tests/"
        }
    },

Nutgall

Answer 3

A non-empty PSR-4 prefix must end with a namespace separator. namespace separator means \\

• Method-1

Incorrect ⬇️⬇️⬇️

"autoload": {
    "psr-4": {
        "Acme\\models" : "app/models"
    }
},

Correct ⬇️⬇️⬇️

"autoload": {
    "psr-4": {
        "Acme\\models" : "app/models/"
    }
},

• Method-2: If this doesn't work try deleting vendor + composer.lock and reinstall dependencies
• Method-3: Delete the autoload_psr4.php file in the libraries folder - it probably was created before the update and it had issues before.

Know more about PSR-4: Autoloader

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