“非空的PSR-4前缀必须以名称空间分隔符结尾”

Question

I am building an app with the following structure:

├── README.md
├── composer.json
├── index.php
└── src
    └── test.php

... and my composer.json file looks like this:

{
    "minimum-stability" : "alpha",
    "name" : "patrick/changedetection",
    "description" : "A change detection script for observing additions to web pages",
    "license" : "MIT",
    "autoload" : {
        "psr-4" : {
            "patrick\\changedetection\\" : [
                "src/"
            ]
        }
    }
}

But when I run composer install , I get

[InvalidArgumentException] A non-empty PSR-4 prefix must end with a namespace separator.

What do I need to do in order to correctly autoload my test.php file?

===

Edit: This is using Composer version 1.8.4.

Answer 1

I think you have one square brackets more than you need... try to remove them it will be like:

{
    "minimum-stability" : "alpha",
    "name" : "patrick/changedetection",
    "description" : "A change detection script for observing additions to web pages",
    "license" : "MIT",
    "autoload" : {
         "psr-4" : {
              "patrick\\changedetection\\" : "src/"
         }
     }
}

Answer 2

If you need to search for a prefix on single location the no need to add it in.

documentation:

https://getcomposer.org/doc/04-schema.md#psr-4 That's why your solution would be

{
    "minimum-stability" : "alpha",
    "name" : "patrick/changedetection",
    "description" : "A change detection script for observing additions to web pages",
    "license" : "MIT",
    "autoload" : {
         "psr-4" : {
              "patrick\\changedetection\\" : "src/"
         }
     }
}

If you need to search for a same prefix in multiple directories, you can specify them as an array as such:

{
    "autoload": {
        "psr-4": { "Monolog\\": ["src/", "lib/"] }
    }
}

Answer 3

As i had the same problem, i found my solution on the composer's website, and here i paste it:

Under the psr-4 key you define a mapping from namespaces to paths, relative to the package root. When autoloading a class like Foo\\Bar\\Baz a namespace prefix Foo\\ pointing to a directory src/ means that the autoloader will look for a file named src/Bar/Baz.php and include it if present. Note that as opposed to the older PSR-0 style, the prefix (Foo\\) is not present in the file path.

Namespace prefixes must end in \\ to avoid conflicts between similar prefixes. For example Foo would match classes in the FooBar namespace so the trailing backslashes solve the problem: Foo\\ and FooBar\\ are distinct.

The PSR-4 references are all combined, during install/update, into a single key => value array which may be found in the generated file vendor/composer/autoload_psr4.php.

Example:

{
"autoload": {
    "psr-4": {
        "Monolog\\": "src/",
        "Vendor\\Namespace\\": ""
    }
}
}

If you need to search for a same prefix in multiple directories, you can specify them as an array as such:

{
"autoload": {
    "psr-4": { "Monolog\\": ["src/", "lib/"] }
}
}

If you want to have a fallback directory where any namespace will be looked for, you can use an empty prefix like:

{
"autoload": {
    "psr-4": { "": "src/" }
}
}

Composer psr-4 Doc