package_prefixed_library_names

The library name is not a dot-separated path prefixed by the package name.

The analyzer produces this diagnostic when a library has a name that doesn't follow these guidelines:

• Prefix all library names with the package name.
• Make the entry library have the same name as the package.
• For all other libraries in a package, after the package name add the dot-separated path to the library's Dart file.
• For libraries under lib, omit the top directory name.

For example, given a package named my_package, here are the library names for various files in the package:

Assuming that the file containing the following code is not in a file named special.dart in the lib directory of a package named something (which would be an exception to the rule), the analyzer produces this diagnostic because the name of the library doesn't conform to the guidelines above:

library something.special;

Change the name of the library to conform to the guidelines.

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-05-08. View source or report an issue.